阅读说明：本技术 用于扬声器驱动器的运动的非线性控制的方法和系统 (Method and system for non-linear control of motion of speaker driver ) 是由 帕斯卡尔·M·布吕内 于 2019-01-17 设计创作，主要内容包括：一个实施例提供了一种倒相式音箱扩音器系统,包括：扬声器驱动器；以及,控制器,被配置为接收经由驱动器进行再现的源信号,基于系统的第一物理模型确定驱动器的目标位移和目标声压,以及基于目标位移、目标声压和系统的第二物理模型生成控制电压。另一个实施例提供了一种被动式辐射器扩音器系统,包括：主动式扬声器驱动器；以及,控制器,被配置为接收用于经由驱动器进行再现的源信号,基于系统的第一物理模型确定组件的目标位移,以及基于目标位移和系统的第二物理模型生成控制电压。在这两个实施例中,基于所生成的控制电压来控制再现期间驱动器的实际位移。(One embodiment provides a phase inversion type loudspeaker system comprising: a speaker driver; and a controller configured to receive a source signal reproduced via the driver, determine a target displacement and a target sound pressure of the driver based on a first physical model of the system, and generate a control voltage based on the target displacement, the target sound pressure, and a second physical model of the system. Another embodiment provides a passive radiator loudspeaker system comprising: an active speaker driver; and a controller configured to receive the source signal for reproduction via the driver, determine a target displacement of the component based on a first physical model of the system, and generate a control voltage based on the target displacement and a second physical model of the system. In both embodiments, the actual displacement of the drive during reproduction is controlled based on the generated control voltage.)

1. A phase inversion loudspeaker system comprising:

A speaker driver including a diaphragm; and

A controller configured to:

Receiving a source signal for reproduction via the speaker driver;

Determining a target displacement of the diaphragm and a target sound pressure in the inverse loudspeaker system based on a first physical model of the inverse loudspeaker system;

Generating a control voltage based on the target displacement, the target sound pressure, and a second physical model of the phase-inverted loudspeaker system; and

During reproduction of the source signal, the actual displacement of the diaphragm is controlled based on the generated control voltage.

2. The inverting speaker and loudspeaker system of claim 1 wherein the controller is further configured to:

Determining a target current to be drawn by the speaker driver based on the target displacement, the target sound pressure, and the second physical model;

Monitoring an actual current drawn by the speaker driver during reproduction of the source signal;

Generating a prediction error based on a comparison of the target current and the actual current;

Compensating for at least one inaccuracy associated with the second physical model or audio drift by adjusting at least one loudspeaker parameter of the second physical model based on the prediction error.

3. The inverting loudspeaker system of claim 1 wherein the control voltage is determined to limit the actual displacement of the diaphragm to within a safe displacement and to increase bass output at frequencies below a threshold.

4. The inverse loudspeaker system of claim 1 wherein the first physical model is a linear state space model,

Wherein the second physical model is a non-linear model.

5. The inverting loudspeaker system of claim 1 further comprising:

An amplifier coupled to the speaker driver and the controller, the amplifier configured to amplify the source signal based on the generated control voltage.

6. A passive radiator loudspeaker system comprising:

An active speaker driver including a diaphragm; and

A controller configured to:

Receiving a source signal for reproduction via the active speaker driver;

Determining a target displacement of a component of the passive radiator loudspeaker system based on a first physical model of the passive radiator loudspeaker system;

Generating a control voltage based on the target displacement and a second physical model of the passive radiator loudspeaker system; and

Controlling an actual displacement of the diaphragm of the active speaker driver based on the generated control voltage during reproduction of the source signal.

7. The passive radiator loudspeaker system as recited in claim 6, wherein the passive radiator loudspeaker system further comprises a passive radiator, and

Wherein the target displacement is a target displacement of the passive radiator.

8. The passive radiator loudspeaker system of claim 6, wherein the target displacement is a target displacement of the diaphragm of the active speaker driver.

9. The passive radiator loudspeaker system of claim 6, wherein the controller is further configured to:

Determining a target current to be drawn by the active speaker driver based on the target displacement and the second physical model;

Monitoring an actual current drawn by the active speaker driver during reproduction of the source signal;

Generating a prediction error based on a comparison of the target current and the actual current; and

Compensating for at least one inaccuracy associated with the second physical model or audio drift by adjusting at least one loudspeaker parameter of the second physical model based on the prediction error.

10. The passive radiator loudspeaker system of claim 8, wherein the control voltage is determined to limit actual displacement of the diaphragm to within a safe displacement range and to increase bass output at frequencies below a threshold.

11. The passive radiator loudspeaker system of claim 6, wherein the first physical model is a linear state space model,

Wherein the second physical model is a non-linear model.

12. The passive radiator loudspeaker system of claim 6, further comprising:

An amplifier coupled to the active speaker driver and the controller, the amplifier configured to amplify the source signal based on the generated control voltage.

13. A method, comprising:

Receiving a source signal reproduced via a speaker driver of a loudspeaker device;

Determining a target displacement of a component of the loudspeaker device based on a first physical model of the loudspeaker device; and

Generating a control voltage based on the target displacement and a second physical model of the loudspeaker device;

Wherein an actual displacement of a diaphragm of the loudspeaker driver during reproduction of the source signal is controlled based on the generated control voltage.

14. The method of claim 13, wherein the loudspeaker device is a phase-inverted loudspeaker system and the target displacement is a target displacement of the diaphragm of the speaker driver,

Wherein the method further comprises:

Determining a target sound pressure in the inverse speaker-microphone system based on the first physical model, wherein the generated control voltage is further based on the target sound pressure.

15. The method of claim 13, wherein the loudspeaker device is a passive radiator loudspeaker system comprising a passive radiator, and the target displacement is one of a target displacement of the diaphragm of the speaker driver or a target displacement of the passive radiator.

Technical Field

One or more embodiments relate generally to loudspeakers, and more particularly to methods and systems for nonlinear control of motion of speaker drivers.

Background

Loudspeakers produce sound when connected to integrated amplifiers, Television (TV) sets, radios, music players, electronic sound producing devices (e.g., smart phones, computers), video players, and the like.

Disclosure of Invention

Solution to the problem

One embodiment provides a phase inversion type loudspeaker system comprising a speaker driver including a diaphragm and a controller. The controller is configured to: receiving a source signal for reproduction via a speaker driver; determining target displacement of a vibrating diaphragm and target sound pressure in the phase inversion type loudspeaker system based on a first physical model of the phase inversion type loudspeaker system; and generating a control voltage based on the target displacement, the target sound pressure, and a second physical model of the inverse speaker-microphone system. During reproduction of the source signal, the actual displacement of the diaphragm is controlled on the basis of the generated control voltage.

Another embodiment provides a passive radiator loudspeaker system that includes an active speaker driver including a diaphragm and a controller. The controller is configured to: receiving a source signal for reproduction via an active speaker driver; determining a target displacement of a component of the passive radiator loudspeaker system based on a first physical model of the passive radiator loudspeaker system; and generating a control voltage based on the target displacement and a second physical model of the passive radiator loudspeaker system. During reproduction of the source signal, the actual displacement of the diaphragm of the active loudspeaker driver is controlled on the basis of the generated control voltage.

One embodiment provides a method comprising: receiving a source signal for reproduction via a loudspeaker driver of a loudspeaker device; determining a target displacement of a component of the loudspeaker device based on a first physical model of the loudspeaker device; and generating a control voltage based on the target displacement and a second physical model of the loudspeaker device. During reproduction of the source signal, the actual displacement of the diaphragm of the loudspeaker driver is controlled on the basis of the generated control voltage.

These and other features, aspects, and advantages of one or more embodiments will become understood with reference to the following description, appended claims, and accompanying drawings.

Drawings

FIG. 1 illustrates an example nonlinear control system in accordance with an embodiment;

Fig. 2A shows a cross section of an example active speaker driver of a loudspeaker device according to an embodiment;

Fig. 2B is an example graph illustrating nonlinear dynamics of different electromechanical parameters for an active speaker driver according to an embodiment;

Fig. 3A shows sound pressures for a phase inversion type loudspeaker system according to an embodiment;

FIG. 3B is an example graph illustrating frequency responses of different loudspeaker parameters for a phase-inverted cabinet loudspeaker system according to an embodiment;

FIG. 4 illustrates an example controller for a phase inversion speaker and microphone system according to an embodiment;

FIG. 5 is an example graph comparing frequency responses of an inverted speakerphone system with non-linear control and a different inverted speakerphone system without non-linear control according to an embodiment;

Fig. 6A illustrates sound pressures in a passive radiator loudspeaker system according to an embodiment;

Fig. 6B is an example graph illustrating frequency responses of different loudspeaker parameters for a passive radiator loudspeaker system in accordance with an embodiment;

Fig. 7 illustrates an example controller for a passive radiator loudspeaker system according to an embodiment;

Fig. 8 is an example graph comparing frequency responses of a passive radiator loudspeaker system with non-linear control and a different passive radiator loudspeaker system without non-linear control, in accordance with an embodiment;

FIG. 9 is an example flowchart of a process for implementing a nonlinear control system for an inverting speaker-microphone system according to an embodiment;

Fig. 10 is an example flow diagram of a process for implementing a non-linear control system for a passive radiator loudspeaker system in accordance with an embodiment; and

FIG. 11 is a high-level block diagram illustrating an information handling system including a computer system for implementing various disclosed embodiments.

Detailed Description

The following description is made for the purpose of illustrating the general principles of one or more embodiments and is not meant to limit the inventive concepts claimed herein. In addition, certain features described herein can be used in combination with other described features in each of the various possible combinations and permutations. Unless otherwise explicitly defined herein, all terms are to be given their broadest possible interpretation, including meanings implied in the specification and meanings understood by those skilled in the art and/or defined in dictionaries, papers, etc.

One or more embodiments relate generally to loudspeakers, and more particularly to methods and systems for nonlinear control of motion of speaker drivers. One embodiment provides a phase inversion type loudspeaker system comprising a speaker driver including a diaphragm and a controller. The controller is configured to: receiving a source signal for reproduction via a speaker driver; determining target displacement of a vibrating diaphragm and target sound pressure in the phase inversion type loudspeaker system based on a first physical model of the phase inversion type loudspeaker system; and generating a control voltage based on the target displacement, the target sound pressure, and a second physical model of the inverse speaker-microphone system. During reproduction of the source signal, the actual displacement of the diaphragm is controlled on the basis of the generated control voltage.

Another embodiment provides a passive radiator loudspeaker system that includes an active speaker driver including a diaphragm and a controller. The controller is configured to: receiving a source signal for reproduction via an active speaker driver; determining a target displacement of a component of the passive radiator loudspeaker system based on a first physical model of the passive radiator loudspeaker system; and generating a control voltage based on the target displacement and a second physical model of the passive radiator loudspeaker system. During reproduction of the source signal, the actual displacement of the diaphragm of the active loudspeaker driver is controlled on the basis of the generated control voltage.

One embodiment provides a method comprising: receiving a source signal for reproduction via a loudspeaker driver of a loudspeaker device; determining a target displacement of a component of the loudspeaker device based on a first physical model of the loudspeaker device; and generating a control voltage based on the target displacement and a second physical model of the loudspeaker device. During reproduction of the source signal, the actual displacement of the diaphragm of the loudspeaker driver is controlled on the basis of the generated control voltage.

For purposes of illustration, the terms "loudspeaker" and "loudspeaker device" may be used interchangeably in this specification.

For purposes of illustration, the terms "inverted cabinet" and "inverted cabinet loudspeaker system" may be used interchangeably in this specification.

For purposes of illustration, the terms "displacement" and "offset" may be used interchangeably in this specification.

Conventional loudspeakers are non-linear in design and generate harmonic components, intermodulation products and modulation noise. Non-linear audio distortion can impair the sound quality (e.g., audio quality and speech intelligibility) of the audio produced by the loudspeaker. In recent years, limitations in industrial design have generally required that loudspeaker systems be small in size for portability and compactness. However, such design constraints limit the portability of the trade size and sound quality, resulting in increased audio distortion. Therefore, there is a need for an anti-distortion system for reducing/eliminating audio distortion, in particular for obtaining more pronounced/loud bass sounds from a loudspeaker system of smaller size.

One or more embodiments provide a non-linear control system for a loudspeaker device comprising an active speaker driver. The nonlinear control system achieves linearization of a loudspeaker device by providing nonlinear control of the conical motion of one or more moving components (e.g., a diaphragm and/or a drive voice coil) of an active speaker driver. In some embodiments, the loudspeaker device is an open-ended loudspeaker (e.g., a phase-inverted cabinet loudspeaker system) that includes an active speaker driver and at least one open-ended enclosure (e.g., an opening/vent). In some embodiments, the loudspeaker device is a passive radiator loudspeaker system comprising an active speaker driver and at least one passive radiator.

In one embodiment, the nonlinear control system is configured to determine the following at each time instant (e.g., each time instant or sample time) from receiving an input voltage for driving the loudspeaker device: (1) a corresponding target displacement (e.g., a target conical displacement) of the one or more movable components based on the target (i.e., desired) acoustic pressure, and (2) generating a corresponding control voltage for the corresponding target displacement. The received input voltage is indicative of a target sound pressure suitable for producing an input audio signal associated with the input voltage. The nonlinear control system controls the conical motion of the one or more movable components at each time instant according to the corresponding control voltage determined for that time instant, thereby generating a target (i.e., desired) sound wave having a target sound pressure. The actual displacement of the one or more movable components at each time instant is based on the corresponding target displacement determined for that time instant, thereby preventing excessive displacement (i.e., offset) of the one or more movable components.

The nonlinear control system can effectively compensate nonlinear audio distortion. By controlling the actual displacement of one or the movable components, the non-linear control system allows bass extension, thereby enhancing the bass output of the loudspeaker device. The non-linear control system provides mechanical protection of the loudspeaker device by preventing excessive displacement of one or more movable components and overheating of the loudspeaker device due to excessive displacement.

In one example implementation, the nonlinear control system is further configured to, at each time from receiving the input voltage: (1) determining a nominal amount of voltage required to obtain the corresponding target displacement determined at that time based on a physical model of the loudspeaker device (e.g., a physical model of an inverted loudspeaker system or a physical model of a passive radiator loudspeaker system), (2) monitoring an amount of current drawn by the loudspeaker device, (3) determining an estimated (i.e., predicted) displacement of the one or more active components based on the amount of current drawn, and (4) performing a voltage correction on the received input voltage based on a difference, if any, between the estimated displacement and the target displacement. In one embodiment, the performed voltage correction includes correcting a feedforward control voltage. In one embodiment, the performed voltage correction may compensate for one or more inaccuracies (e.g., manufacturing variations) associated with the physical model used and/or audio drift (e.g., drift due to overheating of the loudspeaker device due to excessive displacement).

One or more embodiments provide improved performance in terms of non-linear audio distortion and power consumption compared to conventional loudspeakers. Further, one or more embodiments enable non-linear control of an open-microphone or passive-radiator microphone system.

FIG. 1 illustrates an example nonlinear control system 100 in accordance with an embodiment. The nonlinear control system 100 comprises a loudspeaker device 50, which loudspeaker device 50 comprises an active loudspeaker driver 55 for reproducing sound. In one embodiment, the loudspeaker device 50 is an open loudspeaker (e.g., a phase inversion speaker loudspeaker system) that includes an active speaker driver 55 and at least one open enclosure, as described in detail later herein. In another embodiment, the loudspeaker device 50 is a passive radiator loudspeaker system, as described in detail later herein, comprising an active speaker driver 55 and at least one passive radiator.

In one embodiment, the active speaker driver 55 is a front facing speaker driver. In another embodiment, the active speaker driver 55 is an upward facing driver. In yet another embodiment, the active speaker driver 55 is a face down driver. As described in detail later herein, the active speaker driver 55 includes one or more movable components, such as a diaphragm 56 (fig. 2A) and a drive voice coil 57 (fig. 2A).

An input voltage received at the nonlinear control system 100 for driving the active speaker driver 55 is generally denoted by u. As described in detail later herein, the nonlinear control system 100 also includes a controller 110, the controller 110 configured to receive a source signal (e.g., an input audio signal) having an input voltage u from the input source 10. The controller 110 is further configured to determine, based on the at least one physical model of the loudspeaker device 50, one or more of: (1) target displacement x of one or more movable components (e.g., the diaphragm 56 and/or the drive voice coil 57) at the sample time t, (2) target sound pressure p in the loudspeaker device 50 at the sample time t, and (3) a control voltage that produces the target displacement x at the sample time t 。

In one embodiment, the nonlinear control system 100 further includes an amplifier 60 connected to the loudspeaker device 50 and the controller 110. In one embodiment, amplifier 60 is a voltage amplifier configured to be based on a control voltage To amplify the source signal so as to control the actual displacement of the one or more movable elements during reproduction of the source signal. Specifically, the nonlinear control system 100 controls the voltage by basing the control voltage on the corresponding Voltage correction is performed to control the conical motion of one or more movable components to produce a target sound wave having a target sound pressure. Control voltage The actual displacement of the one or more movable components is limited to within a predetermined range of safe displacement. In another embodiment, amplifier 60 is replaced with a current amplifier.

In one embodiment, the controller 110 is configured to receive source signals from different types of input sources 10. Examples of different types of input sources 10 include, but are not limited to, mobile electronic devices (e.g., smart phones, laptops, tablets, etc.), content playback devices (e.g., televisions, radios, computers, music players such as CD players, video players such as DVD players, dials, etc.), or audio receivers, among others.

In one embodiment, the nonlinear control system 100 may be integrated in, but is not limited to, one or more of the following: computers, smart devices (e.g., smart televisions), bass boxes, wireless and portable speakers, car speakers, and the like.

In one embodiment, the controller 110 uses a different physical model for the loudspeaker device 50. In one example implementation, as described in detail later herein, at least one physical model used by the controller 110 is a linear model (e.g., a linear state space model), while at least one other physical model used by the controller 110 is a non-linear model. The physical model of the loudspeaker device 50 may be based on one or more loudspeaker parameters of the loudspeaker device 50.

Fig. 2A shows a cross section of an example active speaker driver 55 of a loudspeaker device 50 according to an embodiment. Active speaker driver 55 includes one or more moving components, such as a diaphragm 56 (e.g., a cone diaphragm) and a drive voice coil 57. The active speaker driver 55 also includes one or more of the following components: (1) encircling roller 58 (e.g., a roller with overhanging edges), (2) basket 59, (3) protective cap 60 (e.g., a dome-shaped dust cap), (4) top plate 61, (5) magnet 62, (6) bottom plate 63, (7) pole piece 65, (8) shaper 64, and (9) bullet wave 67.

Example loudspeaker parameters for loudspeaker device 50 include, but are not limited to, the following for active speaker driver 55 Electrical parameters: (1) a Direct Current (DC) resistor R that drives the voice coil 57. (2) mechanical resistance R of total losses of active speaker driver 55 _m(i.e., mechanical losses), (3) the mechanical mass M of the diaphragm 56, the drive coil 57, and the air load _m(i.e., moving mass), (4) suspension stiffness factor K around the roller 58 _m(5) force factor B1 of driving the voice coil 57, (6) inductance L of driving the voice coil 57 _eAnd (7) the surface area S of the diaphragm 56 _d。

The state of the loudspeaker device 50 at each moment in time is described using each of the following: (1) estimated (i.e., predicted) displacement x of one or more moving components (e.g., diaphragm 56 and/or drive voice coil 57) of active speaker driver 55, (2) velocity of one or more moving components And (3) the current I drawn by driving the voice coil 57.

Fig. 2B is an example graph 150 illustrating nonlinear dynamics of different electromechanical parameters of the speaker driver 55 according to an embodiment. The horizontal axis of graph 150 represents the displacement of one or more movable components (e.g., diaphragm 56 and/or drive voice coil 57) in units of m. Graph 150 includes each of the following: (1) a first curve 151 representing the variation of the force factor Bl in newtons per ampere (N/a), (2) a suspension stiffness factor K in newtons per meter (N/m) _ma second curve 152 of the change, and (3) an inductance L in millihenries (mH) _eA third curve 153 of the variation.

Fig. 3A illustrates sound pressures in an inverting type loudspeaker system 70 according to an embodiment. As described above, in one embodiment, the loudspeaker device 50 is a phase inversion loudspeaker system 70 that includes an active speaker driver 55 and an open enclosure 75 (e.g., an opening/aperture). The inverting type of cabinet loudspeaker system 70 has a higher efficiency at bass frequencies so that the inverting type of cabinet loudspeaker system 70 can achieve significantly more bass output than a closed type of cabinet loudspeaker. Specifically, at low sound frequencies, the open enclosure 75 becomes the primary sound source that supplements one or more of the active components of the active speaker driver 55 (e.g., the diaphragm 56 and/or the drive voice coil 57), resulting in better bass levels (i.e., enhanced bass output) that are confined to a narrow sound frequency range.

By P _VBdGenerally representing the sound pressure generated by one or more moving components, denoted by P _VBpGenerally representing the sound pressure in the enclosure 75 with an opening and is denoted by P _VBGenerally representing the total sound pressure received at a listening entity 90 (e.g., a listener's ear, microphone, etc.) in the vicinity of the phase-inverted loudspeaker system 70. Sound pressure P _VBdSound pressure P _VBpAnd total sound pressure P _VBCan be determined from equations (1) -3 provided below:

And

P_VB＝P_PRd-P_VBp(3)，

Where p is the density of air, Represents the acceleration of the movable component (e.g., diaphragm), r represents the distance in meters (m) between the listening entity 90 and the phase-inverted loudspeaker system 70, and Representing the volumetric acceleration of the air in the open enclosure 75. As shown in fig. 3A, air from the open enclosure 75 moves outward as air from one or more moving components moves inward. Thus, the sound pressure P is shown in FIG. 3A _VBpExpressed as a negative value, and is derived from the sound pressure P in equation (3) _PRdMinus sound pressure P _VBp。

For phase-inverted enclosures, in addition to the electromechanical parameters for the active loudspeaker driver 55 Other loudspeaker parameters of the loudspeaker system 70 include, but are not limited to, the following: (1) total loss acoustic resistance R of the open enclosure 75 _a(2) acoustic mass M of air in the vented enclosure 75 _a(3) an acoustic stiffness factor K of the air in the housing with openings 75 _VBb(4) the volume velocity q in the opening, and (5) the sound pressure p in the inverter type speaker-microphone system 70.

Fig. 3B is an example graph 160 illustrating frequency responses for different loudspeaker parameters for a phase-inverted cabinet loudspeaker system according to an embodiment. The horizontal axis of graph 160 represents frequency in Hz. Graph 160 includes each of the following: (1) a first curve 161 representing a frequency response of an estimated displacement x of one or more movable components (e.g., a diaphragm and/or a drive voice coil) of an inverted loudspeaker system (e.g., inverted loudspeaker system 70) in meters per volt (m/V), (2) a second curve 162 representing a velocity of one or more movable components in meters per second per volt (m/s/V) A third curve 163 representing the frequency response of the impedance Z of the active loudspeaker driver of the inverse speaker loudspeaker system in ohms, and (4) a fourth curve 164 representing the frequency response of the impedance Z of the active loudspeaker driver of the inverse speaker loudspeaker system in cubic meters per second per volt (m) ³/s/V), and (5) a fifth curve 165 representing the frequency response of the sound pressure p in pascals per volt (Pa/V) in the inverse type loudspeaker system.

Fig. 4 illustrates an example controller 200 for an inverting type loudspeaker system 70 according to an embodiment. In one embodiment, the controller 110 of the nonlinear control system 100 is a controller 200. As described in detail later herein, the controller 200 includes: a trajectory planning unit 210 for determining one or more linear values; and a feedforward control unit 220 for determining one or more non-linear values.

In one embodiment, the trajectory planning unit 210 is configured to: (1) determine a target displacement x of one or more movable components of the inverting type loudspeaker system 70 (e.g., the diaphragm 56 and/or the drive voice coil 57) at each sampling time t based on the input voltage u received from the input source 10 and the at least one physical model of the inverting type loudspeaker system 70, and (2) determine a target sound pressure p in the inverting type loudspeaker system 70 at the sampling time t based on the input voltage u and the at least one physical model of the inverting type loudspeaker system 70.

In one embodiment, the trajectory planning unit 210 determines the target displacement x and the target sound pressure p using a linear state space model of the inverse speaker-microphone system 70. For example, in one embodiment, the linear dynamics of the inverting type loudspeaker system 70 may be expressed in accordance with equations (4) -7 provided below.

By X _VB(t) represents a vector representing the state of the inverting loudspeaker system 70 at the sampling time t ("state vector representation"), where the state vector represents X _VB(t) is defined according to equation (4) provided below:

Wherein the content of the first and second substances, Is the speed of one or more moving components. For purposes of illustration, item X _VB(t) and item X _VBAnd may be used interchangeably in this specification.

In one embodiment, the acoustical resistance R associated with the open enclosure 75 _VBAnd acoustic mass M _aMay be a state vector representation X _VBFor example, the volume velocity q in the open enclosure 75.

With A _VBAnd B _VBThe ensemble represents a constant parameter matrix. In one embodiment, the constant parameter matrix A _VBAnd B _VBAccording to equation (5) -side provided below Equation (6) shows:

And

By using Generally representing the state vector X of the inverse speaker-microphone system 70 _VBTime derivative (i.e., rate of change) ("rate of change of state vector"), where the rate of change of state vector is Is defined according to differential equation (7) provided below:

The trajectory planning unit 210 is configured to determine a target displacement x and a target sound pressure p at each sampling time t based on equation (7) provided above.

In one embodiment, the feedforward control unit 220 is configured to: (1) determining a control voltage that may produce the target displacement x based on the target displacement x and the target sound pressure p at the sampling time t received from the trajectory planning unit 210 and at least one other physical model of the inverting loudspeaker system 70 And (2) determining a target current i to be drawn by the active speaker driver 55 for producing the target displacement x based on the target displacement x, the target sound pressure p, and the at least one other physical model of the inverse speaker microphone system 70.

In one embodiment, the feedforward control unit 220 determines the control voltage using a non-linear model for the inverse speaker-microphone system 70 And a target current i. For example, in one embodiment, the nonlinear dynamics for the inverse speaker-microphone system 70 may be expressed in accordance with equations (8) -12 provided below:

Where equation (8) represents the mechanical equation for the active speaker driver 55,

Where equation (9) represents the electrical equation for the active speaker driver 55,

And

In this, equation (10) -equation (11) represent the opening equation of the housing 75 having the opening. Opening equation (10) -opening equation (11) defines a second order linear state space system with inputs, as shown in equation (12) provided below:

In one embodiment, the feedforward control unit 220 implements feedforward control to determine the control voltage for each sampling time t For example, in one embodiment, the feedforward control unit 220 performs a set of calculations including determining to draw through the active speaker driver 55 at the sampling time t based on equation (13) as shown below Target current i taken:

Wherein equation (13) is derived from equation (8) provided above, and the target displacement x and the target sound pressure p of the sampling time t received from the trajectory planning unit 210 are used as inputs (i.e., inputs x and p in equation (13) are replaced by x and p).

The set of calculations performed by the feedforward control unit 220 also includes determining a control voltage for the sampling time t based on equation (14) provided below

Where equation (14) is derived from equation (9) provided above, and the target displacement x and target current i (determined from equation (13) provided above) received from the trajectory planning unit 210 using the sample time t are used as inputs (i.e., inputs x and i in equation (14) are replaced with x and i).

In one embodiment, amplifier 60 is a voltage amplifier configured to be based on a control voltage received from feedforward control unit 220 To amplify the source signal. In another embodiment, the amplifier 60 is a current amplifier configured to amplify the source signal based on a target current i received from the feedforward control unit 220.

In one embodiment, the controller 200 is configured to: the current i drawn by the inverting speaker-microphone system 70 is monitored at each sampling time t and a prediction error for correcting the feedforward control implemented by the feedback control unit 220 is determined based on a comparison between the measured current i and the target current i at the sampling time t. For example, in one embodiment, the controller 200 further includes one or more of the following optional components for implementing feedback control: (1) a comparison unit 240 configured to determine a current error Δ i representing a difference between the current i at the sampling time t and a target current i ×, and (2) a feedback control unit 230 configured to generate one or more model loudspeaker parameter adjustments for correcting the feedforward control implemented by the feedback control unit 220 based on the current error Δ i. For example, in one embodiment, one or more loudspeaker parameters of the non-linear model are adjusted based on the prediction error.

In another embodiment (e.g., where the amplifier 60 is a current amplifier configured to amplify the source signal based on the target current i received from the feed-forward control unit 220), the controller 200 is configured to monitor the voltage u driving the active speaker driver 55 at each sampling time t, and to control the voltage u based on the voltage u at the sampling time t and the control voltage The prediction error for correcting the feedforward control by the feedback control unit 230 is determined. For example, in one embodiment, the comparison unit 240 is configured to determine the voltage u representing the sampling time t and the control voltage The voltage error au of the difference between, and the feedback control unit 230 is configured to generate one or more model microphone parameters comprising a prediction error based on the voltage error au, the one or more model microphone parameters comprising the prediction error for correcting the feedforward control implemented by the feedback control unit 230.

Any final corrections performed based on the generated model microphone parameters may compensate for one or more inaccuracies (e.g., manufacturing variations) associated with the physical model used by the controller 200 and/or audio drift (e.g., due to overheating of the microphone device due to excessive displacement).

In one embodiment, the feedback control implemented by the controller 200 may be adaptive (e.g., online system identification). In another embodiment, the feedback control implemented by the controller 200 may be direct (e.g., proportional-integral-derivative).

In another embodiment, if the active speaker driver 55 has well-known and stable characteristics, the feedforward control unit 220 does not need to take into account any prediction errors, thereby eliminating the need for the feedback control unit 230 and the comparison unit 240.

Fig. 5 is an example graph 400 comparing frequency responses of an inverted speakerphone system with non-linear control and a different inverted speakerphone system without non-linear control, in accordance with an embodiment. The horizontal axis of graph 400 represents frequency in Hz. The vertical axis of graph 400 represents sound pressure level in dB. Graph 400 includes each of the following: (1) a first curve 401 representing the frequency response of a first inverse loudspeaker system (e.g., inverse loudspeaker system 70) with non-linear control, and (2) a second curve 402 representing the frequency response control of a second inverse loudspeaker system without non-linear control. As shown in fig. 5, the frequency response of the second inverse loudspeaker system without non-linear control has a steeper roll-off than the frequency response of the first inverse loudspeaker system with non-linear control.

If the second inverting speakerphone loudspeaker system is integrated with one or more components of the nonlinear control system 100 (e.g., controller 200), the nonlinear control system 100 may expand the roll-off of the frequency response of the second inverting speakerphone loudspeaker system in bass frequencies while maintaining bass distortion and ensuring that the displacement of one or more moving components (e.g., the diaphragm and/or the drive voice coil) of the second inverting speakerphone loudspeaker system is within a safe operating range. The nonlinear control system 100 provides a bass reflex system that achieves bass extension as indicated by the directional arrows shown in fig. 5.

Fig. 6A illustrates sound pressures in a passive radiator loudspeaker system 80 according to an embodiment. As described above, in one embodiment, the loudspeaker device 50 is a passive radiator loudspeaker system 80 that includes the active speaker driver 55 and the passive radiator 85. The passive radiator loudspeaker system 80 has a higher efficiency at low audio frequencies, allowing the passive radiator loudspeaker system 80 to achieve significantly more bass output than a closed enclosure speaker. In particular, at low audio frequencies, the passive radiator 85 becomes the primary sound source that supplements one or more of the active components of the active speaker driver 55 (e.g., the diaphragm 56 and/or the drive voice coil 57), resulting in better bass levels that are confined to a narrow range of sound frequencies. The passive radiator loudspeaker system 80 produces a bass response similar to the inverted cabinet loudspeaker system 70, but the passive radiator loudspeaker system 80 has fewer size limitations, allowing a smaller enclosure/cabinet to be used.

By P _PRdGenerally representing the sound pressure of one or more moving components of the active speaker driver 55 of the passive radiator loudspeaker system 80, denoted by P _PRpGenerally representing the sound pressure in the passive radiator 85 of the passive radiator loudspeaker system 80 and designated by P _PRGenerally representing the total sound pressure received at a listening entity 90 (e.g., a listener's ear, microphone, etc.) in the vicinity of the passive radiator loudspeaker system 80. Sound pressure P _PRdSound pressure P _PRpAnd total sound pressure P _PRCan be determined from equations (15) -17 provided below:

And

P_PR＝P_PRd-P_PRp(17)，

Where p represents the density of the air, Representing the acceleration of the active speaker active component, r representing the listening entity 90 and the passive The distance in meters between the radiator loudspeaker systems 80, and Representing the acceleration of the active component of the passive loudspeaker. As shown in fig. 6A, air from the passive heat sink 85 moves outward as air from one or more moving components moves inward. Thus, the sound pressure P is shown in FIG. 6A _PRpExpressed as a negative value, and is derived from the sound pressure P in equation (3) _PRdMinus sound pressure P _PRp。

In addition to the electromechanical parameters for the active speaker driver 55, other loudspeaker parameters for the passive radiator loudspeaker system 80 include, but are not limited to, the following: (1) an estimated (i.e., predicted) displacement y of the passive radiator 85 (e.g., the diaphragm/diaphragm of the passive radiator 85), (2) a velocity w of the passive radiator 85, (3) a sound pressure p in the acoustic enclosure 80, (4) an acoustic stiffness factor K of the air in the acoustic enclosure 80 _PRb(5) mechanical Mass M of the Passive radiator 85 _p(6) mechanical resistance R of the passive radiator 85 _p(7) suspension stiffness factor K of the passive radiator 85 _pAnd (8) surface area S of passive radiator _p。

Fig. 6B is an example graph 170 illustrating frequency responses of different loudspeaker parameters for a passive radiator loudspeaker system according to an embodiment. The horizontal axis of the graph 170 represents frequency in Hz. The graph 170 includes each of the following: (1) a first curve 171 representing the frequency response in m/V of the estimated displacement x of one or more moving components (e.g., the diaphragm and/or the drive voice coil) of a passive radiator loudspeaker system (e.g., the passive radiator loudspeaker system 80), (2) a second curve 172, which represents the frequency response of the speaker driver impedance Z of the passive radiator loudspeaker system in ohms, (3) a third curve 173, which represents the frequency response of the estimated displacement y of the passive radiator loudspeaker system in m/V, (4) a fourth curve 174, which represents the frequency response of the sound pressure p in the sound box in Pa/V, (5) a fifth curve 175, which represents the frequency response of the velocity w of the passive radiator in m/s/V.

Fig. 7 illustrates an example controller 300 for a passive radiator loudspeaker system 80 according to an embodiment. In one embodiment, the controller 110 of the nonlinear control system 100 is a controller 300. As described in detail later herein, the controller 300 includes: a trajectory planning unit 310 for determining one or more linear values; and a feedforward control unit 320 for determining one or more non-linear values.

In one embodiment, the trajectory planning unit 310 is configured to linearize the displacement of the passive radiator 85. In particular, the trajectory planning unit 310 is configured to: a target displacement y of the passive radiator 85 (e.g., the diaphragm/diaphragm of the passive radiator 85) at each sampling time t is determined based on the input voltage u received from the input source 10 and at least one physical model of the passive radiator loudspeaker system 80.

In one embodiment, the trajectory planning unit 310 determines the target displacement y using a linear state space model of the passive radiator loudspeaker system 80. For example, in one embodiment, the linear dynamics of the passive radiator loudspeaker system 80 can be expressed in accordance with equations (18) -21 provided below.

By X _PR(t) an overall representation vector representing the state of the passive radiator loudspeaker system 80 at the sampling time t ("state vector representation"), where the state vector represents X _PR(t) is defined according to equation (18) provided below:

Where p is the sound pressure in the passive radiator loudspeaker system 80. For purposes of illustration, item X _PR(t) and item X _PRAre used interchangeably in this specification.

With A _PRAnd B _PRThe ensemble represents a constant parameter matrix. In one embodiment, the constant parameter matrix A _PRAnd B _PRAccording to equation (19) -equation (20) provided below ) To show that:

And

By using Generally representing the state vector X of the passive radiator loudspeaker system 80 _PRTime derivative of (a "rate of change of state vector"), wherein the rate of change of state vector Is defined according to differential equation (21) provided below:

The trajectory planning unit 310 is configured to determine the target displacement y at each sampling time t based on equation (21) provided above.

In one embodiment, the feedforward control unit 320 is configured to: (1) determining a control voltage that may produce a target displacement y based on the target displacement y at the sampling time t received from the trajectory planning unit 310 and at least one other physical model of the passive radiator loudspeaker system 80 And (2) determine a target current i to be drawn by the active speaker driver 55 for producing the target displacement y based on the target displacement y and the at least one other physical model of the passive radiator loudspeaker system 80.

In one embodiment, the feedforward control unit 320 uses a non-linear model of the passive radiator loudspeaker system 80 to determine the control voltage And a target current i. For example, in one embodiment, the nonlinear dynamics for the passive radiator loudspeaker system 80 can be expressed in accordance with equations (22) -25 provided below:

Where equation (22) is the mechanical equation for the active speaker driver 55,

Where equation (23) is the electrical equation for the active speaker driver 55,

Wherein equation (24) is the equation for the passive radiator 85, an

Where equation (25) is an equation for the sound pressure in the passive radiator loudspeaker system 80.

In one embodiment, the feedforward control unit 320 implements feedforward control to determine the control voltage for each sampling time t For example, in one embodiment, the feedforward control unit 320 performs a set of calculations that include determining the sound pressure p at the sampling time t based on equation (26) provided as follows:

Where equation (26) is derived from equation (24) provided above, and the target displacement y of the sample time t received from the trajectory planning unit 310 is used as an input (i.e., input y in equation (26) is replaced by y).

The set of calculations performed by the feedforward control unit 320 also includes determining an estimated displacement x of one or more movable components (e.g., the diaphragm 56 and/or the drive coil 57) of the active speaker driver 55 at the sampling time t based on equation (27) provided below:

Where equation (27) is derived from equation (25) provided above and the sound pressure p (determined from equation (26) provided above) and the estimated displacement y of the passive radiator 85 are used as inputs (y ═ y).

The set of calculations performed by the feedforward control unit 320 also includes determining the current i drawn by the active speaker driver 55 at the sampling time t based on equation (28) provided below:

Where equation (28) is derived from equation (22) provided above, and the sound pressure p at the sampling time t (determined according to equation (26) provided above) and the estimated displacement x (determined according to equation (27) provided above) are used as inputs.

The set of calculations performed by the feedforward control unit 320 also includes determining a control voltage for the sampling time t based on equation (29) provided below

Where equation (29) is derived from equation (23) provided above, and the estimated displacement x of the sampling time t (determined according to equation (27) provided above) and the current amount i (determined according to equation (28) provided above) are used as inputs.

In one embodiment, amplifier 60 is a voltage amplifier configured to be based on a control voltage received from feed forward control unit 320 To amplify the source signal. In another embodiment, the amplifier 60 is a current amplifier configured to amplify the source signal based on a target current i received from the feedforward control unit 320.

In one embodiment, the controller 300 is configured to monitor the current i drawn by the passive radiator loudspeaker system 80 at each sampling time t and it determines a prediction error for correcting the feedforward control implemented by the feedback control unit 320 based on a comparison between the current i at the sampling time t and a target current i. For example, in one embodiment, the controller 300 further includes one or more of the following optional components for implementing feedback control: (1) a comparison unit 340 configured to determine a current error Δ i representing a difference between the measured current i and the target current i at the sampling time t, and (2) a feedback control unit 330 configured to generate, based on the current error Δ i, one or more model microphone parameters including a prediction error for correcting the feedforward control implemented by the feedback control unit 330. For example, in one embodiment, one or more loudspeaker parameters of the non-linear model are adjusted based on the prediction error.

In another embodiment (e.g., where the amplifier 60 is a current amplifier configured to amplify the source signal based on the target current i received from the feed-forward control unit 320), the controller 300 is configured to monitor the voltage u driving the active speaker driver 55 at each sample time t, and to control the voltage u based on the voltage u at the sample time t and the control voltage The comparison therebetween determines a prediction error for correcting the feedforward control implemented by the feedback control unit 320. For example, in one embodiment, the comparison unit 340 is configured to determine the voltage u representing the sampling time t and the control voltage Press and press The voltage error au of the difference therebetween, and the feedback control unit 330 is configured to generate one or more model microphone parameters including a prediction error based on the voltage error au, the one or more model microphone parameters including the prediction error for correcting the feedforward control implemented by the feedback control unit 320.

Any final corrections performed based on the generated model microphone parameters may compensate for one or more inaccuracies (e.g., manufacturing variations) associated with the physical model used by the controller 300 and/or audio drift (e.g., due to overheating of the microphone device due to excessive displacement).

In one embodiment, the feedback control implemented by the controller 300 may be adaptive (e.g., online system identification). In another embodiment, the feedback control implemented by the controller 300 may be direct (e.g., proportional-integral-derivative control).

In another embodiment, if the active speaker driver 55 has well-known and stable characteristics, the feedforward control unit 320 does not need to take into account any prediction errors, thereby eliminating the need for the feedback control unit 330 and the comparison unit 340.

In another embodiment, instead of linearizing the passive radiator 85, the trajectory planning unit 310 is configured to linearize the displacement of one or more moving components of the active speaker driver 55 (e.g., the diaphragm 56 and/or the drive voice coil 57). Specifically, the trajectory planning unit 310 is configured to: a target displacement x of the one or more movable components at each sampling time t is determined based on the input voltage u received from the input source 10 and at least one physical model of the passive radiator loudspeaker system 80. Similarly, the feedforward control unit 320 is configured to: determining a control voltage that may produce a target displacement x based on the target displacement x of the sampling time t received from the trajectory planning unit 310 and at least one other physical model of the passive radiator loudspeaker system 80 And a target current i.

Fig. 8 is an example graph 500 comparing frequency responses of a passive radiator loudspeaker system with non-linear control and a different passive radiator loudspeaker system without non-linear control, in accordance with an embodiment. The horizontal axis of graph 500 represents frequency in Hz. The vertical axis of the graph 500 represents sound pressure level in decibels (dB). Graph 500 includes each of the following: (1) a first curve 501 representing the frequency response of a first passive radiator loudspeaker system with non-linear control (e.g., passive radiator loudspeaker system 80), and (2) a second curve 502 representing the frequency response of a second passive radiator system without non-linear control. As shown in fig. 8, the frequency response of the second passive radiator loudspeaker system without nonlinear control has a steeper roll-off than the frequency response of the first passive radiator loudspeaker system with nonlinear control.

If the second passive radiator loudspeaker system is integrated with one or more components of the nonlinear control system 100 (e.g., the controller 300), the nonlinear control system 100 can extend the roll-off of the frequency response of the second non-linear radiator loudspeaker system in bass frequencies while maintaining bass distortion and ensuring that the displacement of one or more moving components (e.g., the diaphragm and/or the drive voice coil) of the second passive radiator loudspeaker system is within a safe operating range. The nonlinear control system 100 provides a bass reflex system that achieves bass extension as indicated by the directional arrows shown in fig. 8.

Fig. 9 is an example flow diagram of a process 700 for implementing a nonlinear control system for an inverting speaker-microphone system according to an embodiment. Processing block 701 includes: a source signal is received that is reproduced via a speaker driver (e.g., active speaker driver 55) of an inverted type loudspeaker system (e.g., inverted type loudspeaker system 70). Processing block 702 includes: a target displacement of one or more movable components of the speaker driver (e.g., diaphragm 56 and/or drive voice coil 57) and a target sound pressure in the inverse loudspeaker system are determined based on the first physical model of the inverse loudspeaker system. Processing block 703 includes: generating a control voltage based on the target displacement, the target sound pressure, and a second physical model of the inverse speaker-loudspeaker system, wherein an actual displacement of the one or more movable components is controlled based on the control voltage during reproduction of the source signal.

In one embodiment, one or more components of the nonlinear control system 100 (e.g., the controller 200) are configured to perform process blocks 701-703.

Fig. 10 is an example flow diagram of a process 800 for implementing a non-linear control system for a passive radiator loudspeaker system according to an embodiment. Processing block 801 includes: a source signal is received that is reproduced via a speaker driver (e.g., active speaker driver 55) of a passive radiator loudspeaker system (e.g., passive radiator loudspeaker system 80). Processing block 802 includes: a target displacement of a component of the passive radiator loudspeaker system (e.g., the passive radiator 85, or one or more moving components of the active speaker driver 55, such as the diaphragm 56 and/or the drive voice coil 57) is determined based on a first physical model of the passive radiator loudspeaker system. Processing block 803 includes: a control voltage is generated based on the target displacement and a second physical model of the passive radiator loudspeaker system, wherein the actual displacement of one or more movable components of the active speaker driver (e.g., the diaphragm 56 and/or the drive voice coil 57) is controlled based on the control voltage during reproduction of the source signal.

In one embodiment, one or more components of the nonlinear control system 100 (e.g., the controller 300) are configured to perform process blocks 801-803.

FIG. 11 is a high-level block diagram illustrating an information processing system including a computer system 600 for implementing various disclosed embodiments. Computer system 600 includes one or more processors 601, and may also include an electronic display device 602 (for displaying video, graphics, text, and other data), a main memory 603 (e.g., Random Access Memory (RAM)), a storage device 604 (e.g., hard disk drive), a removable storage device 605 (e.g., removable storage drive, removable memory module, tape drive, optical drive, computer readable medium having computer software and/or data stored therein), a user interface device 606 (e.g., keyboard, touch screen, keypad, pointing device), and a communication interface 607 (e.g., modem, network interface (e.g., ethernet card), communication port, or PCMCIA slot and card).

Communications interface 607 allows software and data to be transferred between computer system 600 and external devices. The nonlinear controller 600 also includes a communication infrastructure 608 (e.g., a communication bus, crossbar, or network), to which the above-described devices/modules 601-607 are connected.

Information transmitted via communications interface 607 may be in the form of signals, such as electronic, electromagnetic, optical, or other signals capable of being received by communications interface 607 via a signal-bearing communications link, and may be implemented using wire or cable, fiber optics, a telephone line, a cellular telephone link, a Radio Frequency (RF) link, and/or other communications channels. The computer program instructions which represent block diagrams and/or flowchart diagrams herein may be loaded onto a computer, programmable data processing apparatus, or processing device to cause a series of operations to be performed thereon to produce a computer implemented process. In one embodiment, the processing instructions for process 700 (fig. 9) and process 800 (fig. 10) may be stored as program instructions on memory 603, storage device 604, and/or removable storage device 605 for execution by processor 601.

Embodiments have been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products. In some cases, each block of these illustrations/figures, or combinations thereof, can be implemented by computer program instructions. The computer program instructions may also be loaded onto a computer, other than a computer, to cause a series of operational steps to be performed on the computer to produce a computer implemented process such that the instructions which execute via the processor create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. Each block in the flow charts/block diagrams may represent hardware and/or software modules or logic. In alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures, concurrently, and so on.

The terms "computer program medium," "computer usable medium," "computer readable medium," and "computer program product" are used to generally refer to media such as main memory, secondary memory, removable storage drive, a hard disk installed in a hard disk drive, and signals. These computer program products are means for providing software to the computer system. The computer readable medium allows the computer system to read data, instructions, messages or message packets, and other computer readable information from the computer readable medium. The computer readable medium may include, for example, non-volatile memory, such as floppy disks, ROMs, flash memory, disk drive memory, CD-ROMs, and other permanent memory. For example, it may be useful to transfer information, such as data and computer instructions, between computer systems. The computer program instructions may be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

As will be appreciated by those skilled in the art: aspects of the embodiments may be embodied as a system, method or computer program product. Accordingly, aspects of the embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a "circuit," module "or" system. Furthermore, aspects of the embodiments may take the form of a computer program product embodied in one or more computer-readable media having computer-readable program code embodied thereon.

Any combination of one or more computer-readable media may be used. The computer-readable medium may be a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium). A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable high-density disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

computer program code for carrying out operations for aspects of one or more embodiments may be written in any combination of one or more programming languages, including AN object oriented programming language (e.g., Java, Smalltalk, C + +, or the like) and a conventional procedural programming language (e.g., the "C" programming language or a similar programming language).

In some cases, aspects of one or more embodiments are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products. In some cases, it should be understood that: each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer or other programmable data processing apparatus or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Reference in the claims to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more. All structural and functional equivalents that are equivalent to elements of the above-described exemplary embodiments, that are known or later come to be known to those of ordinary skill in the art, are intended to be encompassed by the present claims. Unless the phrase "means for.. or" step for.. is used to explicitly state an element, the element in the claims herein should not be construed in accordance with the provisions of pre-aia35u.s.c. section 112, sixth clause.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the embodiments has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the present disclosure.

Although the embodiments have been described with reference to certain versions thereof; other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.