阅读说明：本技术 信号扰动提取电路、信号扰动提取方法及射频接收器 (Signal disturbance extraction circuit, signal disturbance extraction method and radio frequency receiver ) 是由 王鹏翔 林越 徐健 于 2020-07-27 设计创作，主要内容包括：本发明揭示了一种信号扰动提取电路、信号扰动提取方法及射频接收器,所述信号扰动提取电路并联于信号处理单元的输入端和输出端,包括依次连接于信号处理单元输出端和输入端之间的调制器及滤波器,还包括与调制器和滤波器分别电性连接的电荷泵,其中,所述调制器用于对信号处理单元输出的电压信号进行量化,调制为数字信号；所述电荷泵在数字信号的控制下间断性地向滤波器充电；所述滤波器进行滤波后提取扰动信号,并反馈至信号处理单元输入端。本发明避免了对轨到轨输入范围放大器的依赖,摆脱了轨到轨信号处理的线性度限制,能够简单地提取扰动信号,具有很高的线性度,具有广阔的应用场景。(The invention discloses a signal disturbance extraction circuit, a signal disturbance extraction method and a radio frequency receiver, wherein the signal disturbance extraction circuit is connected in parallel with the input end and the output end of a signal processing unit, comprises a modulator and a filter which are sequentially connected between the output end and the input end of the signal processing unit, and further comprises a charge pump which is respectively and electrically connected with the modulator and the filter, wherein the modulator is used for quantizing a voltage signal output by the signal processing unit and modulating the voltage signal into a digital signal; the charge pump intermittently charges the filter under the control of the digital signal; and the filter extracts the disturbance signal after filtering and feeds the disturbance signal back to the input end of the signal processing unit. The invention avoids the dependence on the rail-to-rail input range amplifier, gets rid of the linearity limitation of the rail-to-rail signal processing, can simply extract the disturbance signal, has very high linearity and has wide application scenes.)

1. A signal disturbance extraction circuit is characterized in that the signal disturbance extraction circuit is connected in parallel with an input end and an output end of a signal processing unit, comprises a modulator and a filter which are sequentially connected between the output end and the input end of the signal processing unit, and further comprises a charge pump which is respectively and electrically connected with the modulator and the filter, wherein the modulator is used for quantizing a voltage signal output by the signal processing unit and modulating the voltage signal into a digital signal; the charge pump intermittently charges the filter under the control of the digital signal; and the filter extracts the disturbance signal after filtering and feeds the disturbance signal back to the input end of the signal processing unit.

2. The signal disturbance extraction circuit according to claim 1, wherein the modulator is a 1-bit modulator, and the modulator is configured to compare the voltage signal with a reference voltage and output a high-low level digital signal, and output a high level if the voltage signal is higher than the reference voltage, and output a low level if the voltage signal is lower than the reference voltage.

3. The signal disturbance extraction circuit of claim 1, wherein the charge pump comprises a control current source connected to a supply voltage and a bias current source connected to a reference voltage, the modulator is electrically connected to the control current source, and the filter is electrically connected between the control current source and the bias current source.

4. The signal disturbance extraction circuit according to claim 1 or 3, wherein the signal disturbance extraction circuit comprises two parallel charge pumps, each for intermittently charging a filter under control of a digital signal to extract a disturbance signal in the differential voltage signal.

5. The signal disturbance extraction circuit of claim 1, wherein the filter is a low pass filter, a high pass filter, or a band pass filter.

6. A signal disturbance extraction method is characterized by comprising the following steps:

s1, acquiring the voltage signal output by the signal processing unit, quantizing the voltage signal through a modulator, and modulating the voltage signal into a digital signal;

s2, controlling the charge pump to intermittently charge the filter through the digital signal;

and S3, filtering by the filter, extracting the disturbance signal, and feeding back the disturbance signal to the input end of the signal processing unit.

7. The signal disturbance extraction method according to claim 6, wherein the step S1 of quantizing the voltage signal by a modulator to obtain a digital signal specifically includes:

and comparing the voltage signal with a reference voltage to output a high-low level digital signal, and if the voltage signal is higher than the reference voltage, outputting a high level, and if the voltage signal is lower than the reference voltage, outputting a low level.

8. The signal disturbance extraction method according to claim 6, wherein the step S2 specifically includes:

a bias current source in the charge pump provides a bias current to the filter;

the digital signal controls a control current source in the charge pump to intermittently charge the filter.

9. The signal disturbance extraction method according to claim 6, wherein the voltage signal is a differential voltage signal;

the step S2 specifically includes: controlling two charge pumps connected in parallel through a digital signal, wherein the two charge pumps respectively and discontinuously charge the filter;

the step S3 specifically includes: and after filtering, the filter extracts a disturbance signal in the differential voltage signal and feeds the disturbance signal back to the input end of the signal processing unit.

10. A radio frequency receiver, characterized in that the radio frequency receiver comprises:

the first signal processing unit comprises a low noise amplifier LNA and/or a low noise transconductance amplifier LNTA and is used for receiving the radio frequency electromagnetic signal and converting the radio frequency electromagnetic signal into an electric signal;

a mixer MIX for mixing the electrical signal and the local oscillator signal to generate a current signal;

the second signal processing unit comprises a transimpedance amplifier TIA and preferably further comprises a programmable gain amplifier PGA, and is used for converting the current signal into a voltage signal;

the filtering unit is used for filtering the voltage signal;

the signal disturbance extraction circuit of any one of claims 1 to 5, wherein the signal disturbance extraction circuit is connected in parallel to an input end and an output end of the second signal processing unit, and the second signal processing unit is further configured to eliminate the disturbance signal extracted by the signal disturbance extraction circuit.

Technical Field

The invention belongs to the technical field of radio frequency signal transmission, and particularly relates to a signal disturbance extraction circuit, a signal disturbance extraction method and a radio frequency receiver.

Background

In a radio frequency signal received by a radar, due to the existence of interference, a low-frequency disturbing signal appears during frequency mixing, which invades the dynamic range of a subsequent analog-to-digital converter (ADC) and influences the resolution precision of the radar. In a conventional rf receiver structure, due to the characteristics of a transimpedance amplifier (also called a current-to-voltage converter TIA), it is not possible to use a conventional high-pass filter to attenuate these low-frequency disturbances.

Referring to fig. 1, a radio frequency receiver in the prior art sequentially includes a low noise amplifier LNA, a low noise transconductance amplifier LNTA, a MIXER MIX, a transimpedance amplifier TIA, a programmable gain amplifier PGA, and a low pass filter LPF, where the low noise amplifier LNA and the low noise transconductance amplifier LNTA convert radio frequency electromagnetic waves received by an antenna into electrical signals, and then the electrical signals are mixed with a local oscillator signal LO through a MIXER, so as to shift a frequency spectrum, generate an intermediate frequency current signal, which is converted into a voltage signal through the transimpedance amplifier TIA and the programmable gain amplifier PGA, and then the voltage signal is filtered by the low pass filter LPF and output.

Due to the objective interference, the if current signal will contain low frequency disturbances, which must be removed by high pass filtering in order to ensure the system works properly. In the conventional radio frequency receiver, in order to ensure the working state of LNTA and MIX, the voltage swing of the TIA input node needs to be limited, and the input impedance of the TIA is strictly limited, so that the conventional feedforward high-pass filter is difficult to apply in the receiver.

Referring to fig. 2, a scheme for eliminating low-frequency disturbance in the prior art specifically includes: and a low-pass filter is connected in parallel with a forward path of the TIA & PGA, and low-frequency disturbance is fed back to the input end of the TIA & PGA in a current form to be eliminated. Due to the output swing of the transimpedance amplifier TIA & programmable gain amplifier PGA, theoretically, a rail-to-rail signal will cause a great limitation to the application of the inverse low pass filter. In such applications, the operational amplifier device of the inverted low pass filter needs to possess a rail-to-rail input range and provide high linearity, increasing design difficulty and cost.

Therefore, in order to solve the above-mentioned technical problems, it is necessary to provide a signal disturbance extraction circuit, a signal disturbance extraction method and a radio frequency receiver.

Disclosure of Invention

The invention aims to provide a signal disturbance extraction circuit, a signal disturbance extraction method and a radio frequency receiver, which are used for extracting and eliminating disturbance in a signal path.

In order to achieve the above object, an embodiment of the present invention provides the following technical solutions:

a signal disturbance extraction circuit is connected in parallel with an input end and an output end of a signal processing unit, comprises a modulator and a filter which are sequentially connected between the output end and the input end of the signal processing unit, and further comprises a charge pump which is respectively and electrically connected with the modulator and the filter, wherein the modulator is used for quantizing a voltage signal output by the signal processing unit and modulating the voltage signal into a digital signal; the charge pump intermittently charges the filter under the control of the digital signal; and the filter extracts the disturbance signal after filtering and feeds the disturbance signal back to the input end of the signal processing unit.

In one embodiment, the modulator is a 1-bit modulator, and the modulator is configured to compare the voltage signal with a reference voltage and output a high-low level digital signal, and output a high level if the voltage signal is higher than the reference voltage, and output a low level if the voltage signal is lower than the reference voltage.

In one embodiment, the charge pump includes a control current source connected to a power voltage and a bias current source connected to a reference voltage, the modulator is electrically connected to the control current source, and the filter is electrically connected between the control current source and the bias current source.

In one embodiment, the signal disturbance extraction circuit comprises two charge pumps connected in parallel, and each charge pump is used for intermittently charging the filter under the control of the digital signal so as to extract the disturbance signal in the differential voltage signal.

In one embodiment, the filter is a low pass filter, a high pass filter, or a band pass filter.

The technical scheme provided by another embodiment of the invention is as follows:

a method of signal disturbance extraction, the method comprising:

s1, acquiring the voltage signal output by the signal processing unit, quantizing the voltage signal through a modulator, and modulating the voltage signal into a digital signal;

s2, controlling the charge pump to intermittently charge the filter through the digital signal;

and S3, filtering by the filter, extracting the disturbance signal, and feeding back the disturbance signal to the input end of the signal processing unit.

In an embodiment, the step S1 of quantizing the voltage signal by using a modulator and modulating the quantized voltage signal into a digital signal specifically includes:

and comparing the voltage signal with a reference voltage to output a high-low level digital signal, and if the voltage signal is higher than the reference voltage, outputting a high level, and if the voltage signal is lower than the reference voltage, outputting a low level.

In an embodiment, the step S2 specifically includes:

a bias current source in the charge pump provides a bias current to the filter;

the digital signal controls a control current source in the charge pump to intermittently charge the filter.

In one embodiment, the voltage signal is a differential voltage signal;

the step S2 specifically includes: controlling two charge pumps connected in parallel through a digital signal, wherein the two charge pumps respectively and discontinuously charge the filter;

the step S3 specifically includes: and after filtering, the filter extracts a disturbance signal in the differential voltage signal and feeds the disturbance signal back to the input end of the signal processing unit.

The technical scheme provided by the further embodiment of the invention is as follows:

a radio frequency receiver, the radio frequency receiver comprising:

the first signal processing unit comprises a low noise amplifier LNA and/or a low noise transconductance amplifier LNTA and is used for receiving the radio frequency electromagnetic signal and converting the radio frequency electromagnetic signal into an electric signal;

a mixer MIX for mixing the electrical signal and the local oscillator signal to generate a current signal;

the second signal processing unit comprises a transimpedance amplifier TIA and preferably further comprises a programmable gain amplifier PGA, and is used for converting the current signal into a voltage signal;

the filtering unit is used for filtering the voltage signal;

in the signal disturbance extraction circuit, the signal disturbance extraction circuit is connected in parallel to the input end and the output end of the second signal processing unit, and the second signal processing unit is further configured to eliminate the disturbance signal extracted by the signal disturbance extraction circuit.

Compared with the prior art, the invention has the following advantages:

the invention avoids the dependence on the rail-to-rail input range amplifier, gets rid of the linearity limitation of the rail-to-rail signal processing, can simply extract the disturbance signal, has very high linearity and has wide application scenes;

the invention can extract and eliminate the disturbance signal with high linearity without changing the equivalent impedance of TIA under the current radio frequency receiver design framework.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a circuit diagram of a prior art RF receiver;

FIG. 2 is a schematic diagram of a prior art inverse low pass filter based signal disturbance extraction circuit;

FIG. 3 is a diagram of a signal disturbance extraction circuit according to a first embodiment of the present invention;

FIG. 4 is a flow chart of a signal disturbance extraction method according to a first embodiment of the present invention;

fig. 5 is a circuit diagram of an rf receiver according to a second embodiment of the present invention.

Detailed Description

The present invention will be described in detail below with reference to embodiments shown in the drawings. The embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to the embodiments are included in the scope of the present invention.

Referring to fig. 3, the signal disturbance extracting circuit in the first embodiment of the present invention, which is connected in parallel to the input end (left port in fig. 3) and the output end (right port in fig. 3) of the signal processing unit, includes a modulator 11 and a filter 12 connected in sequence between the output end and the input end of the signal processing unit, and further includes a charge pump 13 electrically connected to the modulator and the filter, respectively, where the modulator 11 is configured to quantize the voltage signal a output by the signal processing unit and modulate the voltage signal a into a digital signal B; the charge pump 13 intermittently charges the filter 12 under the control of the digital signal B; the filter 12 extracts the disturbance signal C after filtering and feeds back the disturbance signal C to the input end of the signal processing unit.

Correspondingly, referring to fig. 4, the signal disturbance extracting method in the present embodiment includes:

s1, acquiring the voltage signal output by the signal processing unit, quantizing the voltage signal through a modulator, and modulating the voltage signal into a digital signal;

s2, controlling the charge pump to intermittently charge the filter through the digital signal;

and S3, filtering by the filter, extracting the disturbance signal, and feeding back the disturbance signal to the input end of the signal processing unit.

Specifically, the modulator in this embodiment is a 1-bit modulator, and the modulator is configured to compare the voltage signal with a reference voltage and output a high-low level digital signal, and output a high level (1) if the voltage signal is higher than the reference voltage, and output a low level (0) if the voltage signal is lower than the reference voltage.

The charge pump 13 includes a control current source (modulated current) connected to a power voltage and a Bias current source (Bias current) connected to a reference voltage, the modulator 11 is electrically connected to the control current source (modulated current), and the filter 12 is electrically connected between the control current source (modulated current) and the Bias current source (Bias current). The bias current source in the charge pump 13 provides bias current for the filter 12, and the digital signal B controls the control current source in the charge pump 13 to intermittently charge the filter 12, and after passing through the filter, the digital signal B is converted into a disturbance signal C in the form of current.

In this embodiment, the voltage signal a is an intermediate frequency voltage signal, the disturbance signal C is a low frequency disturbance signal, and the corresponding filter 12 is a low pass filter.

The signal processing unit takes the transimpedance amplifier TIA as an example for explanation, quantizes the intermediate frequency voltage signal received by the TIA output end by using the frequency component of the received intermediate frequency, and modulates the intermediate frequency voltage signal into a digital signal B. This process avoids the dependence on the amplifier in the rail-to-rail input range, changes the signal space by the modulation method, and converts the voltage signal into a digital signal, thereby implementing a one-way path from the TIA output terminal to the TIA input terminal, while the signal at the TIA input terminal cannot be fed forward to the output node of the TIA by the signal disturbance extraction circuit described in fig. 3. When a 1-bit modulator is used, it has mathematically perfect linearity.

And the digital signal B obtained by modulation is used for controlling a charge pump, and the charge pump intermittently charges a low-pass filter of an output node under the control of the digital signal B, and converts the low-pass filter into a low-frequency disturbance signal in a current form.

And finally, negatively feeding back the extracted low-frequency disturbance signal to an input end, and eliminating the low-frequency disturbance signal at the input node by the principle of opposite phase and cancellation of amplitude after negative feedback. The elimination of the disturbing signal by negative feedback is a conventional technical means in the field, and is not the core of the protection of the present invention, and will not be described herein.

The key technology improvements of the present invention and the prior art (fig. 2) are: the invention realizes an extraction circuit which only can feed back but does not have a feedforward path, and the normal working signal path is a feedforward path.

Referring to fig. 5, a radio frequency receiver according to a second embodiment of the present invention includes:

a first signal processing unit 20, including a low noise amplifier LNA and a low noise transconductance amplifier LNTA, for receiving the radio frequency electromagnetic signal and converting the radio frequency electromagnetic signal into an electrical signal;

a mixer MIX 30 for mixing the electrical signal and the local oscillator signal to generate a current signal;

a second signal processing unit 40, including a transimpedance amplifier TIA and a programmable gain amplifier PGA, for converting the current signal into a voltage signal;

a filtering unit 50 including a low pass filter LPF for filtering the voltage signal;

and the signal disturbance extraction circuit DCC 10 is connected in parallel with the input end and the output end of the second signal processing unit, and the second signal processing unit is further used for eliminating the disturbance signal extracted by the signal disturbance extraction circuit.

Specifically, in this embodiment, the low noise amplifier LNA and the low noise transconductance amplifier LNTA are sequentially connected in series to the input end of the mixer 30, and convert the received rf electromagnetic signal into an electrical signal, and then the mixer MIX mixes the electrical signal with the local oscillator signal LO to generate an intermediate frequency current signal.

The second signal processing unit 40 is arranged across the transimpedance amplifier TIA and the programmable gain amplifier PGA in an integrated manner, the resistor R1 is an adjustable resistor in the programmable gain amplifier PGA, and in addition, the two ends of the second signal processing unit are connected in parallel with the filter capacitor C1.

The filtering unit 50 is a low pass filter LPF, and a resistor R2 and a capacitor R2 are connected in parallel to both ends of the low pass filter LPF.

In this embodiment, the radio frequency electromagnetic signals are two differential signals, the first signal processing unit converts the two differential radio frequency electromagnetic signals into two differential electrical signals, and the two differential intermediate frequency current signals are generated after mixing by the mixer MIX.

For the differential signal, the signal disturbance extraction circuit in this embodiment includes a modulator, two charge pumps connected in parallel, and a filter, and the two charge pumps connected in parallel are controlled by a digital signal, and are respectively and discontinuously charged to the filter, and the filter extracts the disturbance signal in the differential voltage signal after filtering, and feeds the disturbance signal back to the input end of the signal processing unit. The filter is a low-pass filter to extract low-frequency disturbance signals in the two paths of intermediate-frequency current signals. Specifically, the disturbance extraction principle of each path of signal is the same as that of the first embodiment, and is not described here again.

It should be understood that, in the signal disturbance extraction circuit of this embodiment, two paths of signals multiplex one modulator and one filter, and in other embodiments, one modulator and one filter may be used in each path of signal, that is, each path of signal adopts the circuit structure in the first embodiment, and extraction of the low-frequency disturbance signal may also be achieved.

In addition, in the above embodiment, the low-frequency disturbing signal is taken as an example for description, in other embodiments, the disturbing signals in other frequency ranges may also be extracted, and only different filters need to be selected correspondingly, for example, a high-pass filter or a band-pass filter may be selected, the high-pass filter may be selected to extract the high-frequency disturbing signal, and the band-pass filter may be selected to extract the specific-frequency disturbing signal.

According to the technical scheme, the invention has the following beneficial effects:

the invention avoids the dependence on the rail-to-rail input range amplifier, gets rid of the linearity limitation of the rail-to-rail signal processing, can simply extract the disturbance signal, has very high linearity and has wide application scenes;

the invention can extract and eliminate the disturbance signal with high linearity without changing the equivalent impedance of TIA under the current radio frequency receiver design framework.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.