阅读说明：本技术 一种集成vco式鉴相器及环内混频式锁相环电路 (Integrated VCO (voltage controlled oscillator) type phase discriminator and in-loop mixing type phase-locked loop circuit ) 是由 侯照临 刘武广 张文锋 陈昌锐 王海龙 王燕 金广华 于 2021-06-22 设计创作，主要内容包括：本发明提供了一种集成VCO式鉴相器,包括参考信号处理单元、鉴相单元、反馈信号处理单元、VCO单元、反馈信号选择单元。所述参考信号处理单元对外提供参考信号输入端口,对内与鉴相单元连接；所述VCO单元对外提供调谐电压输入端口与射频信号输出端口,对内与反馈信号选择单元连接；所述反馈信号选择单元对外提供外部反馈信号输入端口,对内与反馈信号处理单元连接,用于选择VCO单元在内部反馈的信号和外部反馈信号输入端口的信号中的一个作为反馈信号处理单元输入信号；所述反馈信号处理单元还与鉴相单元连接；所述鉴相单元对外提供鉴相输出信号输出端口。本发明中的集成VCO式鉴相器的射频反馈回路可选,降低了应用于环内混频式锁相环电路的复杂度,节约成本及功耗。(The invention provides an integrated VCO (voltage controlled oscillator) type phase detector which comprises a reference signal processing unit, a phase detection unit, a feedback signal processing unit, a VCO (voltage controlled oscillator) unit and a feedback signal selection unit. The reference signal processing unit provides a reference signal input port externally and is connected with the phase discrimination unit internally; the VCO unit provides a tuning voltage input port and a radio frequency signal output port to the outside and is connected with the feedback signal selection unit to the inside; the feedback signal selection unit is used for providing an external feedback signal input port for the external, is internally connected with the feedback signal processing unit and is used for selecting one of a signal fed back by the VCO unit from the internal and a signal of the external feedback signal input port as an input signal of the feedback signal processing unit; the feedback signal processing unit is also connected with the phase discrimination unit; the phase discrimination unit provides a phase discrimination output signal output port to the outside. The radio frequency feedback loop of the integrated VCO type phase discriminator is optional, the complexity of the circuit applied to the in-loop mixing type phase-locked loop is reduced, and the cost and the power consumption are saved.)

1. An integrated VCO (voltage controlled oscillator) type phase detector comprises a reference signal processing unit, a phase detection unit, a feedback signal processing unit, a VCO (voltage controlled oscillator) unit, a control interface and other functional part modules, and is characterized by further comprising a feedback signal selection unit. The reference signal processing unit provides a reference signal input port externally and is connected with the phase discrimination unit internally; the VCO unit provides a tuning voltage input port and a radio frequency signal output port to the outside and is connected with the feedback signal selection unit to the inside; the feedback signal selection unit is used for providing an external feedback signal input port for the external, is internally connected with the feedback signal processing unit and is used for selecting one of a signal fed back by the VCO unit from the internal and a signal of the external feedback signal input port as an input signal of the feedback signal processing unit; the feedback signal processing unit is also connected with the phase discrimination unit; the phase discrimination unit provides a phase discrimination output signal output port to the outside; the control interface and other functional part modules are respectively connected with the reference signal processing unit, the phase discrimination unit, the feedback signal processing unit, the VCO unit and the feedback signal selection unit, and externally provide a low-frequency interface for receiving external control and feeding back the working state of each internal unit.

2. The integrated VCO-based phase detector of claim 1 wherein the feedback signal selection element is a radio frequency switch.

3. An in-loop mixing type phase-locked loop circuit based on the integrated VCO-type phase detector of claim 1, comprising the integrated VCO-type phase detector, a mixing processing module and a loop filter; the input end of the loop filter is connected with the phase detection output signal output port of the integrated VCO-type phase detector, and the output end of the loop filter is connected with the tuning voltage input port of the integrated VCO-type phase detector; the output end of the frequency mixing processing module is connected with the external feedback signal input port of the integrated VCO type phase discriminator; and a reference signal is externally provided and input to a reference signal input port of the integrated VCO type phase detector, and a control signal is provided and input to a low-frequency interface of the integrated VCO type phase detector.

4. The in-loop mixing phase-locked loop circuit of claim 3, wherein the in-loop mixing phase-locked loop circuit has a frequency preset mode and an in-loop mixing mode, and when the circuit operates in the frequency preset mode, the feedback signal selection unit selects the VCO internal feedback signal as the input of the feedback signal processing unit; when the circuit operates in the in-loop mixing mode, the feedback signal selection unit selects the external feedback signal as an input of the feedback signal processing unit.

5. The in-loop mixing phase-locked loop circuit of claim 4, wherein the in-loop mixing phase-locked loop circuit supports automatic selection of a VCO output frequency band mode and manual configuration of the VCO output frequency band mode, respectively.

6. The in-loop mixing phase-locked loop circuit of claim 5, wherein the parameters of the in-loop mixing phase-locked loop circuit when operating in the automatic VCO output band mode satisfy the following constraints:

F_vco1＝F_ref×(N₁/R₁)

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

when the VCO works in the manual configuration VCO output frequency band mode, all parameters meet the following constraints:

F_vco1∈[f₁,f₂]and F_vco2∈[f₁,f₂]

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

Wherein, F_refIs the reference signal frequency; f_insTo add signal frequencies; f_vco1Outputting the frequency of the VCO under a frequency preset mode for the circuit to work; f_vco2Outputting the frequency of the VCO under the in-loop mixing mode for the circuit to work; n is a radical of₁、R₁Integrating the radio frequency dividing ratio and the reference frequency dividing ratio of the VCO type phase discriminator when the circuit works in a preset mode and adopts a mode of automatically selecting the VCO output frequency band; f. of₁，f₂The method comprises the steps that a frequency interval boundary where VCO output frequency is located when a VCO output frequency band mode is manually configured; n is a radical of₂、R₂Radio frequency dividing ratio of integrated VCO type phase discriminator when external feedback signal is selected as input of feedback signal processing unit for feedback signal selection unit(ii) a D is the output frequency division ratio of the VCO unit.

7. The in-loop mixing phase-locked loop circuit of claim 5, wherein the integrated VCO type phase detector is configured to not re-enable VCO frequency band automatic selection when the VCO output frequency band mode is selected automatically.

Technical Field

The invention relates to the technical field of radio frequency microwave and chips, in particular to an integrated VCO (voltage controlled oscillator) type phase discriminator and an in-loop mixed frequency type phase-locked loop circuit.

Background

Integrated VCO-based phase detectors are a class of frequency source devices that have begun to appear and develop faster in recent years, and typical models are HMC834, ADF4371, LTC6946, LMX2594, and the like. Although there are "Fractional-N PLL with Integrated VCO" (HMC834), "Microwave with synthesized with Integrated VCO" (ADF4371), "Integrated-N synthesized with Integrated VCO" (LTC6946), "15 GHz broadband PLLATINUM^TMRadio frequency synthesizer "(LMX 2594), etc., are different names, but the same in nature, and are all novel devices formed by integrating a VCO and certain additional functions in a traditional phase detector chip. In the device classification, ADI, Ti and other manufacturers classify the devices together with phase detectors in PLL (phase-locked loop) devices.

The single-ring phase-locked loop can be built by integrating the VCO (particularly integrating the segmented VCO) and certain additional functions inside and adopting an integrated VCO type phase detector and a small amount of configuration circuits. As described above, in each type of integrated VCO-based phase detector, the internally integrated VCO, the phase detector, and the additional functional part have better performance indexes, but the phase noise level and the spurious (especially integer boundary spurious) suppression level of the synthesizer-based single-loop phase-locked loop are difficult to be improved, and the performance of each high index of the integrated VCO-based phase detector is not fully exerted. Meanwhile, in the functional architecture of the existing integrated VCO type phase detector, the VCO output signal is fed back to the phase detector through an internal path inside the chip, and the rf signal feedback cannot be performed from the outside, which limits the application of the integrated VCO type phase detector in the in-loop mixing type phase-locked loop. The integrated VCO type phase discriminator is forcibly used for building the in-loop mixing type phase-locked loop, extra parts such as the phase discriminator need to be added, and the circuit complexity is improved while the waste of cost and power consumption is caused.

Disclosure of Invention

Aiming at the problems in the prior art, the integrated VCO type phase detector and the in-loop mixing type phase-locked loop circuit are provided, so that a radio frequency feedback loop of the integrated VCO type phase detector is selectable, and the application efficiency of the integrated VCO type phase detector in the in-loop mixing type phase-locked loop is improved.

The technical scheme adopted by the invention is as follows: an integrated VCO (voltage controlled oscillator) type phase detector comprises a reference signal processing unit, a phase detection unit, a feedback signal processing unit, a VCO (voltage controlled oscillator) unit, a control interface and other functional parts, and further comprises a feedback signal selection unit. The reference signal processing unit provides a reference signal input port externally and is connected with the phase discrimination unit internally; the VCO unit provides a tuning voltage input port and a radio frequency signal output port to the outside and is connected with the feedback signal selection unit to the inside; the feedback signal selection unit is used for providing an external feedback signal input port for the outside, is internally connected with the feedback signal processing unit and is used for selecting one of a signal fed back by the VCO unit from the inside and a signal of the external feedback signal input port as an input signal of the feedback signal processing unit; the feedback signal processing unit is also connected with the phase discrimination unit; the phase discrimination unit provides a phase discrimination output signal output port to the outside; the control interface and other functional part modules are respectively connected with the reference signal processing unit, the phase discrimination unit, the feedback signal processing unit, the VCO unit and the feedback signal selection unit, and externally provide a low-frequency interface for receiving external control and feeding back the working state of each internal unit.

Further, the feedback signal selection unit is a radio frequency switch.

The invention also provides an in-loop mixing type phase-locked loop circuit based on the integrated VCO (voltage controlled oscillator) type phase detector, which comprises the integrated VCO type phase detector, a mixing processing module and a loop filter; the input end of the loop filter is connected with a phase detection output signal output port of the integrated VCO (voltage controlled oscillator) type phase detector, and the output end of the loop filter is connected with a tuning voltage input port of the integrated VCO type phase detector; the output end of the frequency mixing processing module is connected with the external feedback signal input port of the integrated VCO type phase discriminator; and a reference signal is externally provided and input to a reference signal input port of the integrated VCO type phase detector, and a control signal is provided and input to a low-frequency interface of the integrated VCO type phase detector.

Further, the in-loop mixing type phase-locked loop circuit has a frequency preset mode and an in-loop mixing mode, and when the circuit works in the frequency preset mode, the feedback signal selection unit selects the VCO internal feedback signal as the input of the feedback signal processing unit; when the circuit operates in the in-loop mixing mode, the feedback signal selection unit selects the external feedback signal as an input of the feedback signal processing unit.

Furthermore, the in-loop mixing type phase-locked loop circuit supports automatic selection of a VCO output frequency band mode and manual configuration of the VCO output frequency band mode, and automatic selection and means configuration of the VCO output frequency band are respectively realized.

Further, when the in-loop mixing type phase-locked loop circuit works in the mode of automatically selecting the output frequency band of the VCO, all parameters meet the following constraints:

F_vco1＝F_ref×(N₁/R₁)

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

when the VCO works in the manual configuration VCO output frequency band mode, all parameters meet the following constraints:

F_vco1∈[f₁,f₂]and F_vco2∈[f₁,f₂]

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

Wherein, F_refIs the reference signal frequency; f_insTo add signal frequencies; f_vco1Outputting the frequency of the VCO under a frequency preset mode for the circuit to work; f_vco2Outputting the frequency of the VCO under the in-loop mixing mode for the circuit to work; n is a radical of₁、R₁Integrating the radio frequency dividing ratio and the reference frequency dividing ratio of the VCO type phase discriminator when the circuit works in a preset mode and adopts a mode of automatically selecting the VCO output frequency band; f. of₁，f₂The method comprises the steps that a frequency interval boundary where VCO output frequency is located when a VCO output frequency band mode is manually configured; n is a radical of₂、R₂The feedback signal selection unit selects an external feedback signal as the input of the feedback signal processing unit, and the radio frequency division ratio of the VCO-type phase discriminator is integrated; d is the output frequency division ratio of the VCO unit.

Furthermore, when the VCO output frequency band mode is automatically selected, the VCO frequency band is not automatically selected again when the integrated VCO type phase detector is configured and locked.

Compared with the prior art, the beneficial effects of adopting the technical scheme are as follows:

1. the radio frequency feedback loop of the integrated VCO-type phase detector is optional.

2. The application efficiency of the integrated VCO-type phase detector when applied to the in-loop mixing type phase-locked loop is improved: the phase detector and other parts additionally arranged outside the integrated VCO type phase detector can be omitted, the circuit complexity is reduced, and the cost and the power consumption are saved.

Drawings

Fig. 1 is a block diagram of an integrated VCO-type phase detector according to the present invention.

Fig. 2 is a circuit block diagram of the integrated VCO-type phase detector applied to the in-loop mixing phase-locked loop according to the present invention.

Fig. 3 is a schematic diagram of a phase-locked loop circuit in the prior art.

Fig. 4 is a schematic diagram of a verification circuit of an integrated VCO-based phase detector architecture and application built in an embodiment of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the present invention provides an integrated VCO type phase detector, which includes a reference signal processing unit, a phase detection unit, a feedback signal processing unit, a VCO unit, a control interface, other functional parts, and a feedback signal selection unit. The reference signal processing unit provides a reference signal input port externally and is connected with the phase discrimination unit internally; the VCO unit provides a tuning voltage input port and a radio frequency signal output port for the outside and is connected with the feedback signal selection unit for the inside; the feedback signal selection unit is used for providing an external feedback signal input port for the external, is internally connected with the feedback signal processing unit and is used for selecting one of a signal fed back by the VCO unit from the internal and a signal of the external feedback signal input port as an input signal of the feedback signal processing unit; the feedback signal processing unit is also connected with the phase discrimination unit; the phase discrimination unit provides a phase discrimination output signal output port for the outside; the control interface and other functional part modules are respectively connected with the reference signal processing unit, the phase discrimination unit, the feedback signal processing unit, the VCO unit and the feedback signal selection unit, and externally provide a low-frequency interface for receiving external control and controlling each unit in the integrated VCO type phase discriminator to work; and monitoring the working state of each internal unit and providing a state monitoring interface for the outside.

Preferably, the feedback signal selection unit is an SPDT radio frequency switch.

In this embodiment, the feedback signal selection unit only performs the feedback signal selection function without adding other functions, and the feedback signal processing unit should not be simply understood as a frequency divider and neglects other functions such as amplitude adjustment, so that the output signal of the feedback signal selection unit cannot be directly connected to the phase detection unit, but must pass through the feedback signal processing unit; meanwhile, in a practical implementation form, the feedback signal selection unit can be integrated with the feedback signal processing unit, but the existence of the feedback signal selection unit cannot be ignored in function.

The integrated VCO-type phase discriminator can be directly applied as a single-ring phase-locked loop and can also be applied to an in-loop mixing type phase-locked loop circuit:

when the integrated VCO-type phase detector is applied as a single-ring phase-locked loop, the feedback signal selection unit can be configured to always adopt a signal fed back from the interior of the VCO as an input signal of the feedback signal processing unit, and the design principle, the circuit and the like of the integrated VCO-type phase detector applied to the single-ring phase-locked loop are the same as those of the existing integrated VCO-type phase detector which does not adopt the functional architecture.

When the method is applied to the in-loop mixing type phase-locked loop circuit, the in-loop mixing type phase-locked loop can be formed by externally adding a loop filter and a mixing processing function part, and the method specifically comprises the following steps:

as shown in fig. 2, an in-loop mixing type phase-locked loop circuit based on the integrated VCO type phase detector is provided, which includes an integrated VCO type phase detector, a mixing processing module, and a loop filter; the input end of the loop filter is connected with the phase detection output signal output port of the integrated VCO-type phase detector, and the output end of the loop filter is connected with the tuning voltage input port of the integrated VCO-type phase detector; the output end of the frequency mixing processing module is connected with the external feedback signal input port of the integrated VCO type phase discriminator; and a reference signal is externally provided and input to a reference signal input port of the integrated VCO type phase detector, and a control signal is provided and input to a low-frequency interface of the integrated VCO type phase detector.

The in-loop mixing type phase-locked loop circuit has a frequency preset mode and an in-loop mixing mode, and when the feedback signal selection unit selects the feedback signal in the VCO as the input of the feedback signal processing unit, the circuit works in the frequency preset mode; when the feedback signal selection unit selects an external feedback signal as the input of the feedback signal processing unit, the circuit works in an in-loop mixing mode; the in-loop mixing type phase-locked loop circuit supports automatic selection of a VCO output frequency band mode and manual configuration of the VCO output frequency band mode, and automatic selection and means configuration of the VCO output frequency band are respectively realized.

Specifically, the working process of the in-loop mixing type phase-locked loop circuit is as follows:

1. setting a target RF output frequency F_outAccording to F_outThe required parameters are calculated by combining the following formula, and when the in-loop mixing type phase-locked loop circuit works in the mode of automatically selecting the VCO output frequency band, all the parameters meet the following constraints:

F_vco1＝F_ref×(N₁/R₁)

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

when the VCO works in the manual configuration VCO output frequency band mode, all parameters meet the following constraints:

F_vco1∈[f₁,f₂]and F_vco2∈[f₁,f₂]

Fvco₁≈Fvco₂

|F_vco2/D-F_ins|＝F_ref×N₂/R₂

F_out＝F_vco2/D

Wherein, F_refIs the reference signal frequency; f_insTo add signal frequencies; f_vco1Outputting the frequency of the VCO under a frequency preset mode for the circuit to work; f_vco2Outputting the frequency of the VCO under the in-loop mixing mode for the circuit to work; n is a radical of₁、R₁Integrating the radio frequency dividing ratio and the reference frequency dividing ratio of the VCO type phase discriminator when the circuit works in a frequency preset mode and adopts a mode of automatically selecting the VCO output frequency band; f. of₁，f₂Manually configuring a frequency interval boundary where the VCO output frequency is located when the VCO output frequency band mode is adopted; n is a radical of₂、R₂The feedback signal selection unit selects an external feedback signal as the input of the feedback signal processing unit, and the radio frequency division ratio of the VCO-type phase discriminator is integrated; d is the output frequency division ratio of the VCO unit.

"≈" indicates: when the circuit is operated in the frequency preset mode, the VCO output frequency is not necessarily completely equal to the VCO output frequency in the in-loop mixing mode, but is maintained to include F_VCO2Within a certain frequency rangeThe frequency range is determined by the preferred frequency band of the segmented VCO integrated within the specifically integrated VCO-based phase detector chip for different target output frequencies.

2. The integrated VCO-type phase detector is controlled by an externally provided control signal, and the feedback signal selection unit is configured to select the VCO internal feedback signal as the input of the feedback signal processing unit, namely, the circuit is set to work in a frequency preset mode.

3. In a frequency preset mode, an integrated VCO (voltage controlled oscillator) type phase detector is used for automatically selecting the VCO output frequency band function and simultaneously configuring N₁、R₁Or manually configuring the VCO output frequency band function to cause the VCO output signal frequency to be equal to F_vco1Or at [ f₁，f₂]Preferably, the VCO output band is automatically selected.

4. If the automatic selection VCO output frequency band mode is used, an integrated VCO type phase discriminator needs to be configured, so that the VCO output frequency band is not selected again when the phase discriminator is out of lock; if the VCO output frequency band mode is manually configured, the step is omitted.

5. The feedback signal selection unit is configured to select an external feedback signal as an input of the feedback signal processing unit, namely, the setting circuit works in an in-loop mixing mode.

6. Configuration N₂、R₂And D, if necessary, a mixing function part, F_insAnd F_refSatisfying the equality relation described by formula constraint, obtaining the set target radio frequency output frequency F after the circuit is locked_out。

And when the target radio frequency output frequency changes, repeating the steps 1-6. In the specific case where the new target RF output frequency is within [ f ] described by the constraint equation₁，f₂]The intervals, or in the range constrained by the meaning of "≈" in the constraint equation, may omit steps 2, 3, 4, 5.

As shown in fig. 3, it can be seen that compared with the circuit block diagram of the in-loop mixing type phase-locked loop in the prior art, the in-loop mixing type phase-locked loop is built by using the integrated VCO type phase detector with the functional architecture of the present invention, and an external phase detector and an additional circuit thereof are not required, so that the circuit complexity and cost are reduced, and the application performance of the integrated VCO type phase detector is improved.

In this embodiment, an application verification circuit as shown in fig. 4 is built for verification, and the specific process is as follows:

a) setting a target RF output frequency F_outAnd (5.8 GHz), adopting a VCO (voltage controlled oscillator) output frequency band mode for automatic selection, wherein the setting values of all parameters are as follows: f_ins＝5.7GHz；F_vco1＝2.9GHz；N₁＝29；R₁＝1；N₂＝1；R₂＝1；F_vco22.9 GHz; d ═ 0.5 (i.e., 2 octave mode).

b) And controlling the SPDT radio frequency switch to select the VCO internal feedback signal as the input of the feedback signal processing unit, namely setting the circuit to work in a frequency preset mode.

c) In a frequency preset mode, an integrated VCO (voltage controlled oscillator) type phase detector is used for automatically selecting a VCO (voltage controlled oscillator) output frequency band mode and simultaneously configuring N₁、R₁Obtaining F_vco1＝2.9GHz。

d) And C), turning off the lock losing function to automatically select the VCO output frequency band again, and keeping the VCO output frequency in the same frequency band as the execution result of the step c).

e) And controlling the SPDT radio frequency switch to select an external feedback signal as an input of the feedback signal processing unit, namely setting the circuit to work in an in-loop mixing mode.

f) Configuration N₂＝1、R₂And the VCO unit outputs 2 multiplied signals (D is the mode agreed by 0.5).

g) And obtaining the radio frequency output with the frequency locked at 5.8 GHz.

h) Further, a new target RF output frequency F is set_out5.8GHz +1 kHz. 5.8GHz +1kHz and 5.8GHz are in the same VCO frequency band interval, so that the intermediate process is omitted, and N is kept₂＝1、R₂Configuration F is unchanged at 1_insA radio frequency output frequency locked at 5.8GHz +1kHz was obtained at 5.7GHz +1 kHz.

Example verification shows that the integrated VCO-type phase detector provided by the invention can be completely realized in functional architecture and application thereof, and the scheme provided by the invention realizes that the radio frequency feedback loop of the VCO-type phase detector is selectable; meanwhile, the application efficiency of the integrated VCO-type phase detector when applied to the in-loop mixing type phase-locked loop is improved: the phase detector and other parts additionally arranged outside the integrated VCO type phase detector can be omitted, the circuit complexity is reduced, and the cost and the power consumption are saved.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed. Those skilled in the art should also realize that such insubstantial changes or modifications can be made without departing from the spirit of the invention as defined by the appended claims.

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of mutually exclusive features and/or steps.

Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.