阅读说明：本技术 Fsk解调系统及方法 (FSK demodulation system and method ) 是由 王元鸿 于 2019-03-19 设计创作，主要内容包括：本发明提供一种FSK解调系统及方法。系统包含电力发送器以及电力接收器。电力发送器产生频移键控信号,包含电力信号以及电力调制指示信息。电力接收器在等待时间内检测电力信号的非调制周期。电力接收器接着依据电力调制指示信息调制电力信号的频率以产生脉宽调制信号。电力接收器接着计算脉宽调制信号的完整周期,接着将脉宽调制信号的完整周期减去非调制周期以取得待解调信号。(The invention provides an FSK demodulation system and a method. The system includes a power transmitter and a power receiver. The power transmitter generates a frequency shift keyed signal containing the power signal and power modulation indication information. The power receiver detects a non-modulation period of the power signal during the latency time. The power receiver then modulates the frequency of the power signal according to the power modulation indication information to generate a pulse width modulation signal. The power receiver then calculates the complete period of the pulse width modulated signal, then subtracts the non-modulated period from the complete period of the pulse width modulated signal to obtain the signal to be demodulated.)

1. An FSK demodulation system, comprising:

a power transmitter, comprising:

a power signal generator configured to generate a frequency shift keying signal, the frequency shift keying signal comprising a power signal and power modulation indication information;

a power transmitting inductor connected to the power signal generator and configured to transmit the frequency shift keying signal received from the power signal generator; and

a power receiver connected to the power transmitter, comprising:

a power receiving inductor coupled to the power transmitting inductor and configured to receive the frequency shift keying signal and to respond to a power modulation response signal to the power transmitting inductor within a wait time after receiving the frequency shift keying signal;

a power modulation signal generator, comprising:

a non-modulation period detector connected to the power receiving inductor and configured to detect a non-modulation period of the power signal received by the power receiving inductor within a sampling time;

a power signal modulator connected to the power receiving inductor and configured to modulate the power signal according to the power modulation indication information to generate a pulse width modulation signal;

a complete period calculator connected to the power signal modulator and configured to calculate a complete period of the pulse width modulated signal;

a signal to be demodulated generator connected to the complete period calculator and the non-modulated period detector and configured to subtract the non-modulated period from the complete period of the pulse width modulated signal to generate a signal to be demodulated.

2. The FSK demodulation system according to claim 1, wherein said power receiver further comprises a decoder connected to said signal-to-be-demodulated generator;

the signal generator to be demodulated is configured to generate a critical value according to the waveform parameter of the signal to be demodulated;

the decoder is configured to decode the signal to be demodulated based on the threshold value to obtain a demodulated signal having one or more bit values;

the to-be-demodulated signal generator is configured to output a power demodulation signal according to a modulation parameter of the demodulation signal and the obtained one or more bit values;

the power receiving inductor is configured to respond to the power demodulation signal to the power transmitter after the wait time;

the power transmitter receives the power demodulation signal through the power transmission inductor and then transmits to the power signal generator.

3. The FSK demodulation system of claim 1 wherein the power receiver further comprises a synchronous rectifier connected to the power receiving inductor and the power signal modulator and configured to rectify the power signal received by the power receiving inductor to output a power rectified signal;

the non-modulation period detector is configured to detect the non-modulation period of the power rectified signal within the sampling time;

the power signal modulator is configured to modulate the frequency of the power rectification signal according to the power modulation indication information to generate the pulse width modulation signal;

the complete period calculator calculates the complete period of the pulse width modulation signal;

the signal to be demodulated generator is configured to subtract the non-modulation period from the full period of the pulse width modulated signal to obtain the signal to be demodulated.

4. The FSK demodulation system of claim 1 wherein said signal to be demodulated generator comprises a subtractor.

5. The FSK demodulation system of claim 1 wherein the latency is not less than 1 ms.

6. An FSK demodulation method, comprising the steps of:

generating, with a power signal generator of a power transmitter, a frequency shift keying signal including a power signal and power modulation indication information;

transmitting the frequency shift keying signal received from the power signal generator using a power transmitting inductor of the power transmitter;

receiving the frequency shift keying signal with a power receiving inductor of a power receiver;

detecting, with a non-modulation period detector of the power receiver, a non-modulation period of the power signal received by the power receiving inductor within a sampling time;

modulating, with a power signal modulator of the power receiver, the power signal in accordance with the power modulation indication information to generate a pulse width modulation signal;

calculating a complete period of the pulse width modulation signal with a complete period calculator of the power receiver; and

subtracting the non-modulation period from the full period of the pulse width modulation signal with a signal to be demodulated generator of the power receiver to generate a signal to be demodulated.

7. The FSK demodulation method according to claim 6, wherein said FSK demodulation method further comprises the steps of:

generating a critical value according to a waveform parameter of the signal to be demodulated after the sampling time by using the signal to be demodulated generator of the power receiver;

decoding, by a decoder of the power receiver, the signal to be demodulated based on the threshold value to obtain a demodulated signal having one or more bit values;

generating a demodulation response message according to the modulation parameter of the demodulation signal and the obtained one or more bit values by using the signal to be demodulated generator of the power receiver, and generating a power demodulation signal comprising the demodulation signal and the demodulation response message;

outputting the power demodulation signal after a latency time using the power receiving inductor of the power receiver; and

transmitting, with the power transmitting inductor of the power transmitter, the power demodulation signal received from the power receiving inductor to the power signal generator.

8. The FSK demodulation method according to claim 6, wherein said FSK demodulation method further comprises the steps of:

rectifying, with a synchronous rectifier of the power receiver, the power signal received by the power receiving inductor to output a power rectified signal;

detecting the non-modulation period of the power rectified signal within the sampling time using the non-modulation period detector;

modulating a frequency of the power rectification signal with the power signal modulator of the power receiver in accordance with the power modulation indication information to generate the pulse width modulation signal;

calculating the full period of the pulse width modulated signal with the full period calculator of the power receiver;

subtracting the non-modulation period from the full period of the pulse width modulation signal to obtain the signal to be demodulated, using the signal to be demodulated generator of the power receiver.

9. The FSK demodulation method according to claim 6, wherein said FSK demodulation method further comprises the steps of:

and subtracting the non-modulation period from the complete period of the pulse width modulation signal by utilizing a subtracter of the signal generator to be demodulated to obtain the signal to be demodulated.

Technical Field

The present invention relates to a demodulation system and method, and more particularly, to an FSK demodulation system and method.

Background

In the last decade, the number and variety of portable and mobile devices has exploded. For example, the use of mobile phones, tablet computers, media players, etc. has become ubiquitous. Such devices are usually powered by an internal battery, and their typical use cases usually require recharging the battery or wired powering of the device directly from an external power supply.

Most present day systems require on-line and/or explicit electrical contacts to supply power from an external power supply. But this is often impractical and requires the user to physically insert a connector or otherwise establish physical electrical contact. Furthermore, this practice often causes inconvenience to the user by introducing long online. Typically, power requirements are also quite different, and currently most devices are equipped with their own dedicated power supply, resulting in a typical user having many different power supplies each dedicated to a particular device. Although a wired connection to the power supply during use may no longer be required by using an internal battery, this provides only a partial solution as the battery will need to be recharged (or replaced more expensively). The use of batteries may also add significant weight to the device, potentially increasing cost and size.

In order to provide a significantly improved user experience, it has been proposed to use a wireless power supply in which power is transferred inductively from the transmitter coil in the power transmitter device to the receiver coil in each individual device. Power delivery by magnetic induction is a well-known concept that is mainly applied in transformers and has a tight coupling between the primary transmitter coil and the secondary receiver coil. By separating the primary transmitter coil and the secondary receiver coil between the two devices, wireless power transfer between these coils is possible based on the principle of a loosely coupled transformer.

Such an arrangement allows wireless power transfer to the device without any need to make any on-line or physical electrical connections. Indeed, such an arrangement may simply allow the device to be placed near or on the transmitter coil in order to recharge or power it from the outside.

Furthermore, such a wireless power transfer arrangement may advantageously be designed such that the power transmitter device may be used for a variety of power receiver devices. In particular, the wireless power transfer standard, referred to as the Qi standard, has been defined and is currently being developed further. This standard allows power transmitter devices meeting the Qi standard to be used for power receiver devices also meeting the Qi standard without requiring that these power transmitter devices and power receiver devices are from the same manufacturer or have to be dedicated to each other. The Qi standard also comprises some functionality for allowing the operation to be adapted to a specific power receiver device (e.g. depending on a specific power consumption).

Disclosure of Invention

The present invention provides an FSK demodulation system, which includes a power transmitter and a power receiver, for overcoming the drawbacks of the prior art. The power transmitter includes a power signal generator and a power transmitting inductor. The power signal generator is configured to generate a frequency shift keying signal, the frequency shift keying signal comprising a power signal and power modulation indication information. The power transmitting inductor is connected to the power signal generator and configured to transmit the frequency shift keying signal received from the power signal generator. The power receiver is connected with the power transmitter. The power receiver includes a power receiving inductor and a power modulation signal generator. The power receiving inductor is coupled to the power transmitting inductor. The power receiving inductor is configured to receive a frequency shift keying signal and to respond to a power modulation response signal to the power transmitting inductor after a wait time following receipt of the frequency shift keying signal. The power modulation signal generator comprises a non-modulation period detector, a power signal modulator, a complete period calculator and a signal generator to be demodulated. The non-modulation period detector is connected to the power receiving inductor. The non-modulation period detector is configured to detect a non-modulation period of the power signal received by the power receiving inductor within a sampling time. The power signal modulator is connected to the power receiving inductor. The power signal modulator is configured to modulate the power signal according to the power modulation indication information to generate a pulse width modulation signal. The complete cycle calculator is connected with the power signal modulator. The full period calculator is configured to calculate a full period of the pulse width modulated signal. The signal generator to be demodulated is connected with the complete period calculator and the non-modulation period detector. The signal to be demodulated generator is configured to subtract the non-modulation period from the full period of the pulse width modulated signal to generate a signal to be demodulated.

Preferably, the power receiver further comprises a decoder connected to the signal generator to be demodulated; the signal to be demodulated generator is configured to generate a critical value according to the waveform parameter of the signal to be demodulated; the decoder is configured to decode the signal to be demodulated based on a threshold value to obtain a demodulated signal having one or more bit values; the to-be-demodulated signal generator is configured to output a power demodulation signal according to the modulation parameter of the demodulation signal and the obtained one or more bit values; the power receiving inductor is configured to respond to a power demodulation signal to the power transmitter after a wait time; the power transmitter receives the power demodulation signal through the power transmission inductor and then transmits to the power signal generator.

Preferably, the power receiver further comprises a synchronous rectifier connected to the power receiving inductor and the power signal modulator, configured to rectify the power signal received by the power receiving inductor to output a power rectified signal; the non-modulation period detector is configured to detect a non-modulation period of the power rectification signal within a sampling time; the power signal modulator is configured to modulate the frequency of the power rectification signal according to the power modulation indication information to generate a pulse width modulation signal; a complete period calculator calculates a complete period of the pulse width modulation signal; the signal to be demodulated generator is configured to subtract the non-modulation period from the full period of the pulse width modulated signal to obtain the signal to be demodulated.

Preferably, the signal to be demodulated generator comprises a subtractor.

Preferably, the waiting time is not less than 1 ms.

In addition, the invention provides an FSK demodulation method, which comprises the following steps: generating, with a power signal generator of a power transmitter, a frequency shift keying signal including a power signal and power modulation indication information; transmitting, with a power transmitting inductor of a power transmitter, a frequency shift keying signal received from a power signal generator; receiving, with a power receiving inductor of a power receiver, a frequency shift keying signal; detecting, with a non-modulation period detector of the power receiver, a non-modulation period of the power signal received by the power receiving inductor within the sampling time; modulating the power signal according to the power modulation indication information by using a power signal modulator of the power receiver to generate a pulse width modulation signal; calculating a complete period of the pulse width modulation signal using a complete period calculator of the power receiver; and subtracting the non-modulation period from the complete period of the pulse width modulation signal to generate a signal to be demodulated, using a signal to be demodulated generator of the power receiver.

Preferably, the FSK demodulation method further comprises the steps of:

generating a critical value according to the waveform parameter of the signal to be demodulated after sampling time by using a signal to be demodulated generator of the power receiver; decoding a signal to be demodulated based on a threshold value by using a decoder of the power receiver to obtain a demodulated signal having one or more bit values; generating a demodulation response message by using a signal generator to be demodulated of the power receiver according to the modulation parameter of the demodulation signal and the obtained one or more bit values, and generating a power demodulation signal comprising the demodulation signal and the demodulation response message; outputting a power demodulation signal after the waiting time using a power receiving inductor of the power receiver; and transmitting, with the power transmitting inductor of the power transmitter, the received power demodulation signal from the power receiving inductor to the power signal generator.

Preferably, the FSK demodulation method further comprises the steps of: rectifying, with a synchronous rectifier of the power receiver, the power signal received by the power receiving inductor to output a power rectified signal; detecting a non-modulation period of the power rectification signal within a sampling time by using a non-modulation period detector; modulating the frequency of the power rectification signal by a power signal modulator of the power receiver according to the power modulation indication information to generate a pulse width modulation signal; calculating a complete period of the pulse width modulation signal using a complete period calculator of the power receiver; and subtracting the non-modulation period from the complete period of the pulse width modulation signal by using a signal generator to be demodulated of the power receiver to obtain the signal to be demodulated.

Preferably, the FSK demodulation method further comprises the steps of: and subtracting the non-modulation period from the complete period of the pulse width modulation signal by utilizing a subtracter of the signal generator to be demodulated to obtain the signal to be demodulated.

As described above, the FSK demodulation system and method provided by the present invention modulate the frequency of the frequency shift keying signal received from the power transmitter by the power receiver to adjust the power to obtain the pulse width modulated signal, and then automatically subtract the non-modulation period (i.e. the non-modulation period of the unadjusted frequency shift keying signal) from the complete period of the pulse width modulated signal to obtain the signal to be demodulated. A threshold value is generated according to the waveform parameter of the signal to be demodulated (the threshold value is independent of the PWM period), and the signal to be demodulated is successfully decoded based on the threshold value. In this way, the present invention eliminates the need for other equipment machines to re-detect different coil parameter values for different power transmitters and power receivers to set different threshold values for decoding the transmitted signal as the coil is replaced as in conventional demodulation systems. Therefore, the invention can effectively improve the mass production efficiency of the system.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

Fig. 1 is a circuit layout diagram of a power transmitter and a power receiver of an FSK demodulation system according to an embodiment of the present invention.

Fig. 2 is a detailed circuit diagram of the FSK demodulation system according to the first embodiment of the present invention.

Fig. 3 is a layout diagram of an internal circuit of a power receiver of an FSK demodulation system according to a second embodiment of the present invention.

Fig. 4 is a signal waveform diagram of an FSK demodulation system according to a third embodiment of the present invention.

Fig. 5 is a flowchart illustrating a FSK demodulation method according to a fourth embodiment of the present invention.

Fig. 6 is a flowchart illustrating a FSK demodulation method according to a fifth embodiment of the present invention.

Fig. 7 is a flowchart illustrating a FSK demodulation method according to a sixth embodiment of the present invention.

Detailed Description

The following is a description of embodiments of the present invention with reference to specific embodiments, and those skilled in the art will understand the advantages and effects of the present invention from the contents provided in the present specification. The invention is capable of other and different embodiments and its several details are capable of modifications and various changes in detail, all without departing from the spirit and scope of the present invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the contents are not provided to limit the scope of the present invention.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

[ first embodiment ]

Referring to fig. 1 and fig. 2, fig. 1 is a circuit layout diagram of a power transmitter and a power receiver of an FSK demodulation system according to an embodiment of the present invention; fig. 2 is a detailed circuit diagram of the FSK demodulation system according to the first embodiment of the present invention.

As shown in fig. 1 and 2, the FSK demodulation system 1 includes a power transmitter TX and a power receiver RX. The power transmitter TX includes a power signal generator TG, a power transmitting inductor TL, and an amplitude shift keying signal receiver TAR. The power transmitting inductor TL is connected to the power signal generator TG.

The power receiver RX includes a power receiving inductor RL, a power modulation signal generator RG, and an amplitude shift keying signal generator RAG. The power receiving inductor RL is connected to a power modulation signal generator RG. The power transmitting inductor TL and the power receiving inductor RL may be components wound in a coil shape with a wire having an inductive property. The power transmitting inductor TL of the power transmitter TX electromagnetically couples the power receiving inductor RL of the power receiver RX.

Electromagnetic induction may be generated between the power transmitting inductor TL of the power transmitter TX and the power receiving inductor RL of the power receiver RX so that the power signal generator TG and the power modulation signal generator RG may perform bidirectional power signal transmission. The power signal generator TG transmits power to the power modulation signal generator RG with a Frequency-Shift Keying (FSK) signal.

As shown in fig. 2, power modulated signal generator RG of power receiver RX may include a non-modulation period detector 40, a power signal modulator 50, a complete period calculator 60, and a signal-to-be-demodulated generator 70. The power receiving inductor RL is connected to the non-modulation period detector 40 and the power signal modulator 50. The power signal modulator 50 is connected to the complete cycle calculator 60. The to-be-demodulated signal generator 70 is connected to the non-modulation period detector 40 and the complete period calculator 60.

First, the power signal generator TG of the power transmitter TX is configured to generate a frequency shift keying signal FSK. The frequency shift keyed signal FSK contains the power signal PS and power modulation indication information 112. The power modulation instruction information 112 includes the frequency, pulse width, period, power level, and the like of the adjusted power signal PS. The power transmission inductor TL of the power transmitter TX is configured to transmit a frequency shift keying signal FSK to the power receiver RX upon receiving the frequency shift keying signal FSK generated by the power signal generator TG.

When the power receiving inductor RL of the power receiver RX electromagnetically senses the frequency shift keying signal FSK transmitted by the power transmitting inductor TL of the power transmitter TX, the power receiving inductor RL transmits the frequency shift keying signal FSK to the non-modulation period detector 40 and the power signal modulator 50 of the power modulation signal generator RG of the power receiver RX.

It should be understood that the signal transmission between the power receiving inductor RL of the power receiver RX and the power transmitting inductor TL of the power transmitter TX must have a latency (such as the latency TR of fig. 4). For example, the power receiver RX transmits information to the power transmitter TX by way of the amplitude shift keying signal ASK, and the amplitude shift keying signal TAR decodes the amplitude shift keying signal ASK and then responds to the information of the power receiver RX by way of the frequency shift keying signal FSK after a waiting time has elapsed.

It should be noted that, in the present embodiment, the unmodulated period detector 40 of the power receiver RX is configured to detect the unmodulated period of the power signal PS received by the power receiving inductor RL within the sampling time included in the waiting time, and then output the detected unmodulated period DEC to the to-be-demodulated signal generator 70 of the power receiver RX. This Power signal PS may be a Power signal conforming to the Qi standard developed by the Wireless Power Consortium. In the present embodiment, the non-modulation period DEC is a non-modulation period within the sampling time TDC in the power signal PS.

On the other hand, the power signal modulator 50 of the power receiver RX is configured to modulate the frequency of the power signal PS according to the power modulation indication information 112 to generate the pulse width modulation signal PWMS. After the power signal modulator 50 of the power receiver RX modulates the power signal PS, the complete cycle calculator 60 of the power receiver RX may receive the pulse width modulation signal PWMS from the power signal modulator 50. The complete period calculator 60 then calculates a complete period TAF of the pulse width modulation signal PWMS, and then outputs the pulse width modulation signal PWMS and the detected complete period TAF of the pulse width modulation signal PWMS to the signal-to-be-demodulated generator 70.

Further, the signal-to-be-demodulated generator 70 receives the non-modulation period DEC of the power signal PS from the non-modulation period detector 40 and receives the pulse width modulation signal PWMS having the complete period TAF modulated by the power signal PS from the complete period calculator 60. The to-be-demodulated signal generator 70 then subtracts the non-modulation period DEC from the full period TAF of the pulse width modulated signal PWMS to generate the to-be-demodulated signal WDES.

The signal-to-be-demodulated generator 70 of the electric power modulation signal generator RG may output the signal-to-be-demodulated WDES to the amplitude shift keying signal generator RAG. The decoder or an additional component with decoding function included in the amplitude shift keying signal generator RAG may decode the signal to be demodulated WDES to generate the demodulated signal.

The amplitude shift keying signal generator RAG may modulate the modulation parameter of the pwm signal PWMS (or modulate the power rectified signal PRS as shown in fig. 3 to the pwm signal PWMRS) according to the power signal PS and the decoded signal WDES to be demodulated to generate the demodulated signal. The amplitude shift keying signal generator RAG may then adjust the amplitude of the demodulated signal to generate the amplitude shift keying signal ASK for transmission to the power receiving inductor RL.

The power receiver RX may then be electromagnetically coupled with the power transmitting inductor TL of the power transmitter TX through the power receiving inductor RL in response to the amplitude shift keying signal ASK to the power transmitter TX. The power transmitting inductor TL of the power transmitter TX may output the amplitude shift keying signal ASK received from the power receiving inductor RL of the power receiver RX to the amplitude shift keying signal receiver TAR of the power transmitter TX.

Further, if it is required to confirm whether the amplitude shift keying signal ASK is correct, the amplitude shift keying signal receiver TAR may receive the frequency shift keying signal FSK from the power signal generator TG. Next, the amplitude shift keying signal receiver TAR may determine whether the power receiver RX adjusts the power signal PS of the frequency shift keying signal FSK to the adjusted power signal included in the amplitude shift keying signal ASK indicated by the power modulation indication information 112. Alternatively, the amplitude shift keying signal receiver TAR transmits the amplitude shift keying signal ASK received from the power transmitting inductor TL to the power signal generator TG, and the above-described determination operation is performed by the power signal generator TG.

[ second embodiment ]

Please refer to fig. 3, which is a layout diagram of an internal circuit of a power receiver of an FSK demodulation system according to a second embodiment of the present invention. The FSK demodulation system of the present embodiment includes a power transmitter and a power receiver RX. The power receiver RX may be electromagnetically coupled with the power transmitter.

As shown in fig. 3, power receiver RX includes a power receiving inductor RL and a power modulation signal generator RG. The power receiving inductor RL may be connected to the power modulation signal generator RG through a capacitance. Power modulated signal generator RG may include a non-modulation period detector 40, a power signal modulator 50, a complete period calculator 60, a signal-to-be-demodulated generator 70, a decoder 80, and a synchronous rectifier 90.

First, the power receiver RX electromagnetically couples the power transmitter to inductively receive the frequency shift keying signal FSK transmitted by the power transmitter through the power receiving inductor RL. In the present embodiment, it is defined that the frequency shift keying signal FSK includes the power signal PS and the power modulation indication information 112. The power receiver RX then transmits a frequency shift keyed signal FSK to the synchronous rectifier 90. The synchronous rectifier 90 may be, for example, a half-wave rectifier or a full-wave rectifier. The synchronous rectifier 90 rectifies the waveform of the power signal PS of the frequency shift keyed signal FSK to produce a power rectified signal PRS. The synchronous rectifier 90 then outputs a power rectified signal PRS to the power signal modulator 50 and the non-modulated period detector 40 either synchronously or asynchronously.

The power signal modulator 50 is configured to determine power adjustment parameter values indicated by the power modulation indication information 112 of the FSK signal, modulate the frequency or other parameter values of the power rectified signal PRS according to the power adjustment parameter values, and then adjust the power of the power rectified signal PRS to generate the pwm signal PWMRS. The complete period calculator 60 may then calculate a complete period TAFR output of the pulse width modulation signal PWMRS to the signal to be demodulated generator 70.

After or while the power signal modulator 50 and the complete period calculator 60 perform the above-described operations, the non-modulation period detector 40 may calculate the non-modulation period DEC of the power rectified signal PRS at the sampling time to output to the signal-to-be-demodulated generator 70.

The to-be-demodulated signal generator 70 may be a subtractor configured to subtract the non-modulation period DEC from the complete period TAFR of the pwm signal PWMRS to obtain the to-be-demodulated signal WDMS, and output the to-be-demodulated signal WDMS to the decoder 80. The to-be-demodulated signal generator 70 may generate the threshold value according to the waveform parameter of the to-be-demodulated signal WDMS (or the to-be-demodulated signal WDES). For example, the threshold TH of the signal to be demodulated is an average value of the peak value and the valley value of the signal to be demodulated, which is only illustrated herein, but the present invention is not limited thereto, and in fact, the threshold can be any value suitable for the subsequent decoding operation.

When the decoder 80 receives the signal to be demodulated WDES from the signal to be demodulated generator 70, the decoder 80 is configured to decode the signal to be demodulated WDES based on the threshold value TH to obtain the demodulated signal DES. The demodulation signal DES may be represented by binary bit values, for example the demodulation signal DES may have one or more bit values or a bit stream.

[ third embodiment ]

Please refer to fig. 4, which is a signal waveform diagram of an FSK demodulation system according to a third embodiment of the present invention. As shown in fig. 4, the power transmitter TX and the power receiver RX may perform bidirectional signal transmission. The time during which the power transmitter TX waits to receive the signal transmitted by the power receiver RX and the time during which the power receiver RX waits to receive the signal transmitted by the power transmitter TX is the waiting time TR. The power transmitter TX transmits a frequency shift keying signal FSK to the power receiver RX, and after the waiting time TR, the power receiver RX responds to the corresponding amplitude shift keying signal ASK to the power transmitter TX according to the frequency shift keying signal FSK received from the power transmitter TX. When the power transmitter TX receives the amplitude shift keying signal ASK from the power receiver RX, the power transmitter TX responds to the corresponding frequency shift keying signal FSK to the power receiver RX according to the amplitude shift keying signal ASK after the waiting time TR. This waiting time TR is not less than 1ms, for example.

It is noted that the conventional FSK demodulation system does not usually perform any task, particularly, does not perform a task of detecting a non-modulation period of a frequency shift keying signal during a waiting time. However, in the present embodiment, the power receiver RX detects a non-modulation period of the frequency shift keying signal FSK, for example, samples N pulses of a plurality of pulses in the frequency shift keying signal FSK, within the sampling time TDC of the waiting time TR to calculate a non-modulation period of the N pulses, i.e., a non-modulation period in the frequency shift keying signal FSK.

The power receiver RX may rectify and modulate the frequency of the frequency shift keyed signal FSK to generate a pulse width modulated signal PWMRS having a complete period TAFR. The power receiver RX may subtract the full period TAFR, e.g. 285, of the pulse width modulated signal PWMRS by the non-modulated period, e.g. 274, to obtain the signal to be demodulated WDES having a period TRD, e.g. 11. The power receiver RX may then calculate a threshold value TH of the signal to be demodulated WDES, and decode the signal to be demodulated WDES based on the threshold value TH to obtain the demodulated signal DES. For example, the demodulation signal DES may include a Bi-phase Mark Code (BMC) or other suitable codes, which are only exemplary and not intended to limit the present invention.

[ fourth embodiment ]

Please refer to fig. 5, which is a flowchart illustrating a FSK demodulation method according to a fourth embodiment of the present invention. As shown in fig. 5, the FSK demodulation method of the present embodiment includes the following steps S501 to S517, which are applied to the FSK demodulation system of the above embodiment, to demodulate, by the power receiver, the frequency shift keying signal received from the power transmitter.

In step S501, a frequency shift keying signal containing a power signal and power modulation indication information is generated using a power signal generator of a power transmitter.

In step S503, the frequency shift keying signal is transmitted using the power transmission inductor of the power transmitter.

In step S505, a frequency shift keying signal is received using a power receiving inductor of the power receiver.

In step S507, a non-modulation period of the power signal is detected within the sampling time using a non-modulation period detector of the power receiver.

In step S509, a full period of the pulse width modulation signal is calculated by the full period calculator of the power receiver.

In step S511, the power signal modulator of the power receiver modulates the frequency of the power signal according to the power modulation indication information to generate a pulse width modulation signal.

In step S513, the non-modulation period is subtracted from the full period of the pulse width modulation signal by the to-be-demodulated signal generator of the power receiver to generate the to-be-demodulated signal.

In step S515, a threshold value is generated by the to-be-demodulated signal generator of the power receiver according to the waveform parameter of the to-be-demodulated signal.

In step S517, the power receiver decoder decodes the signal to be demodulated based on the threshold value to obtain a demodulated signal. For example, the demodulated signal may include a bi-phase identification code.

It should be understood that the sequence of steps described herein can be adjusted according to actual requirements, for example, the sequence of steps S507 and S509 can be switched or executed simultaneously, which is only for illustration, and the present invention is not limited to the sequence and combination of steps in the embodiments herein.

[ fifth embodiment ]

Please refer to fig. 6, which is a flowchart illustrating a FSK demodulation method according to a fifth embodiment of the present invention. As shown in fig. 6, the FSK demodulation method of the present embodiment includes the following steps S601 to S607, and is applied to the FSK demodulation system of the above embodiment. After the demodulation of the frequency shift keying signal is completed in the above steps S501 to 517, steps S601 to S607 can be executed to respond the amplitude shift keying signal from the power receiver to the power transmitter.

In step S601, the amplitude of the demodulated signal is adjusted by the power signal modulator of the power receiver to generate an amplitude shift keying signal.

In step S603, an amplitude shift keying signal is output using the power receiving inductor of the power receiver.

In step S605, the amplitude shift keying signal is received from the power receiving inductor using the power transmitting inductor of the power transmitter.

In step S607, the amplitude shift keying signal is transmitted to the amplitude shift keying signal receiver of the power transmitter using the power transmitting inductor of the power transmitter.

[ sixth embodiment ]

Please refer to fig. 7, which is a flowchart illustrating a FSK demodulation method according to a sixth embodiment of the present invention. As shown in fig. 7, the FSK demodulation method of the present embodiment includes the following steps S701 to S713, and is applied to the FSK demodulation system of the above embodiment.

In step S701, a power signal received by a power receiving inductor from a power transmitter is rectified with a synchronous rectifier of the power receiver to output a power rectified signal.

In step S703, a non-modulation period of the power rectification signal is detected within a sampling time by a non-modulation period detector.

In step S705, the power signal modulator of the power receiver modulates the frequency of the power rectification signal according to the power modulation indication information to generate a pulse width modulation signal.

In step S707, a full period of the pulse width modulation signal is calculated with the full period calculator of the power receiver.

In step S709, the power receiver subtracts the non-modulation period from the full period of the pwm signal in the generator of the signal to be demodulated to obtain the signal to be demodulated.

In step S711, a threshold is generated by the to-be-demodulated signal generator of the power receiver according to the waveform parameter of the to-be-demodulated signal.

In step S713, the power receiver decoder is used to decode the signal to be demodulated based on the threshold value to obtain the demodulated signal.

[ advantageous effects of the embodiments ]

In summary, the FSK demodulation system and method provided by the present invention modulate the frequency of the FSK signal received from the power transmitter by the power receiver to adjust the power to obtain the pwm signal, then automatically subtract the non-modulation period (i.e. the non-modulation period of the non-adjusted FSK signal) from the full period of the pwm signal to obtain the signal to be demodulated, generate the threshold value of the pulse of the signal to be demodulated, and successfully decode the signal to be demodulated based on the threshold value. In this way, the present invention eliminates the need for other equipment machines to re-detect different coil parameter values for different power transmitters and power receivers to set different threshold values for decoding the transmitted signal as the coil is replaced as in conventional demodulation systems. Therefore, the invention can effectively improve the mass production efficiency of the system.

The above-mentioned embodiments are only preferred embodiments of the present invention, and not intended to limit the scope of the claims of the present invention, so that all equivalent technical changes made by using the contents of the specification and the drawings are included in the scope of the claims of the present invention.