WO2020124446A1

WO2020124446A1 - Self-test circuit, self-test device and receiver

Info

Publication number: WO2020124446A1
Application number: PCT/CN2018/122130
Authority: WO
Inventors: 王丹; 杨光
Original assignee: 鹤壁天海电子信息系统有限公司
Priority date: 2018-12-19
Filing date: 2018-12-19
Publication date: 2020-06-25

Abstract

Provided are a self-test circuit, a self-test device and a receiver. The self-test circuit is used to test a channel gain of a zero intermediate frequency receiver. The zero intermediate frequency receiver at least comprises a zero intermediate frequency demodulator. The self-test circuit at least comprises an oscillator and a mixer circuit. A first output end of the oscillator is connected to a first input end of the mixer circuit. An output end of the mixer circuit is connected to a first input end of the zero intermediate frequency demodulator. A second output end of the oscillator is further connected to a second input end of the zero intermediate frequency demodulator. The oscillator is used to generate a local oscillator signal. The mixer circuit receives a pulse signal from a second input end thereof, and mixes the local oscillator signal and the pulse signal to generated a mixed signal. The zero intermediate frequency demodulator demodulates the mixed signal according to the local oscillator signal to obtain a channel gain. The self-test circuit of the present invention can improve the test accuracy of a channel gain of a receiver and mitigate the influence of an ambient environment.

Description

Self-checking circuit, self-checking device and receiver

Technical field

This application relates to the field of receivers, and in particular to a self-check circuit, self-check device, and receiver.

Background technique

The zero-IF architecture has the advantages of high integration, small size, low cost, and low power consumption. More and more handheld devices use the zero-IF architecture. In order to ensure the reliability and attendance of equipment with zero-IF architecture, the equipment needs to be self-checked before use.

At present, the self-checking technology of the zero-IF receiver is flawed. The most fundamental problem is that the signal has been moved into the DC frequency band from the beginning. There is strong low-frequency interference and noise in this frequency band, which makes the signal not yet obtained enough. The gain is "polluted", and the DC drift caused by the leakage of the local oscillator signal is the most serious. It can easily mask the useful signal. At the same time, the DC drift is not constant and changes with the surrounding environment. The size of the reflected leakage signal changes, that is, the variability of DC drift with time.

Technical solution

The present application provides a self-check circuit, a self-check device, and a receiver to solve the problem of inaccurate self-check caused by DC drift.

In order to solve the above technical problems, the present application provides a self-check circuit, which is used to detect the channel gain of a zero-IF receiver. The zero-IF receiver includes at least a zero-IF demodulator, and the self-test circuit includes at least an oscillator and Mixing circuit; the first output of the oscillator is coupled to the first input of the mixing circuit, the output of the mixing circuit is coupled to the first input of the zero-IF demodulator, and the second output of the oscillator Further coupled with the second input terminal of the zero-IF demodulator; wherein, the oscillator is used to generate a local oscillator signal, and the second input terminal of the mixing circuit is used to receive a pulse signal, and the local oscillator signal and the pulse signal Mixing is performed to generate a mixed signal, and the zero-IF demodulator demodulates the mixed signal according to the local oscillator signal to obtain the channel gain.

In order to solve the above technical problems, the present application also provides a self-checking device for detecting the channel gain of the zero-IF receiver; the self-checking device includes a driving power supply and a self-checking circuit, and the self-checking circuit includes the above Self-test circuit.

To solve the above technical problems, the present application also provides a receiver including the above-mentioned self-checking device; the receiver further includes a radio frequency circuit, the radio frequency circuit is coupled to the self-checking device, and the radio frequency circuit is used to input a radio frequency signal.

In this application, the self-test circuit is used to detect the channel gain of the zero-IF receiver. The zero-IF receiver includes at least a zero-IF demodulator, the self-test circuit includes at least an oscillator and a mixing circuit; the output terminal of the oscillator is mixed with The first input terminal of the frequency circuit is coupled, the first output terminal of the mixing circuit is coupled to the first input terminal of the zero intermediate frequency demodulator, and the second output terminal of the oscillator is further connected to the first input terminal of the zero intermediate frequency demodulator Two input terminals are coupled; wherein, the oscillator is used to generate a local oscillator signal, and the second input terminal of the mixing circuit is used to receive a pulse signal, and the local oscillator signal and the pulse signal are mixed to generate a mixed signal, zero The intermediate frequency demodulator demodulates the mixed signal according to the local oscillator signal to obtain the channel gain; this application mixes the local oscillator signal and the pulse signal through the mixing circuit to generate a mixed signal, and then mixes according to the local oscillator signal The signal is demodulated to obtain a demodulated signal, and the demodulated signal is compared with the local oscillator signal to obtain the channel gain. Since the demodulated signal is an AC signal, it can effectively reduce the effect of DC drift and improve the accuracy of the channel gain obtained by self-test. Sex.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions in the embodiments of the present invention, the drawings required in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For a person of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings. among them:

FIG. 1 is a schematic structural diagram of Embodiment 1 of a self-check circuit of this application;

2 is a schematic structural diagram of Embodiment 2 of a self-check circuit of this application;

3 is a schematic structural diagram of Embodiment 3 of a self-check circuit of this application;

4 is a schematic structural diagram of Embodiment 4 of a self-check circuit of this application;

5 is a schematic diagram of the waveform of the I channel after demodulation in FIG. 4;

6 is a schematic diagram of the waveform of the Q channel after demodulation in FIG. 4;

7 is a schematic structural diagram of the principle of the self-check circuit in FIG. 4;

8 is a waveform diagram of the amplitude of the self-check signal in FIG. 7;

9 is a waveform diagram of the amplitude of the I and Q signals after demodulation in FIG. 7;

10 is a schematic structural view of an embodiment of a self-checking device of the present application;

11 is a schematic structural diagram of an embodiment of a receiver of the present application.

Embodiments of the invention

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. It can be understood that the specific embodiments described herein are only used to explain the present application, not to limit the present application. In addition, it should be noted that, in order to facilitate description, the drawings only show parts, but not all structures related to the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

Please refer to FIG. 1, which is a schematic structural diagram of Embodiment 1 of a self-check circuit of the present application. The self-checking circuit 100 disclosed in this embodiment is applied to a zero-IF receiver, and specifically applied to detect the channel gain of the zero-IF receiver. The zero-IF receiver 101 includes at least a zero-IF demodulator 13.

As shown in FIG. 1, the self-test circuit 100 disclosed in this embodiment at least includes an oscillator 11, a mixing circuit 12 and a zero-IF demodulator 13.

The first output terminal of the oscillator 11 is coupled to the first input terminal of the mixer circuit 12, the output terminal of the mixer circuit 12 is coupled to the first input terminal of the zero-IF demodulator 13, and the first The two output terminals are further coupled to the second input terminal of the zero-IF demodulator 13.

The oscillator 11 is used to generate a local oscillator signal, and the oscillator 11 outputs the local oscillator signal to the zero-IF demodulator 13 and the mixing circuit 12; the first input terminal of the mixing circuit 12 receives the local oscillator signal, and the second input terminal Receive pulse signal. Among them, the pulse signal is a discrete signal, which is continuously sent out according to a certain voltage amplitude and a certain time interval. The pulse signal is generated by a pulse signal generator (not shown in the figure); the mixing circuit 12 is used to The local oscillator signals are mixed to produce mixed signals.

The first input terminal of the zero-IF demodulator 13 receives the mixed signal, and the second input terminal receives the local oscillator signal; in the zero-IF demodulator 13, the mixed signal is demodulated according to the local oscillator signal to obtain the channel gain ; Among them, the zero-IF demodulator 13 demodulates the mixed signal according to the local oscillator signal to generate a modulated signal, which can be an AC signal; the channel gain is the ratio between the modulated signal and the local oscillator signal.

In this embodiment, the mixing circuit 12 mixes the local oscillator signal and the pulse signal to obtain a mixed signal, and transmits the mixed signal to the zero intermediate frequency demodulator 13; the zero intermediate frequency demodulator 13 according to the local oscillator signal Demodulate the mixed signal to obtain an AC signal, and compare the ratio of the AC signal to the local oscillator signal to obtain the channel gain of the self-test circuit 100. Since the signal in the self-test circuit 100 is demodulated, the obtained It is an AC signal. The AC signal will not be affected by the environment, such as temperature and other environmental factors, which can effectively improve the accuracy of the channel gain of the self-test circuit 300.

Please refer to FIG. 2, which is a schematic structural diagram of Embodiment 2 of the self-check circuit of the present application. The self-test circuit 100 disclosed in this embodiment includes the oscillator 11, the mixing circuit 12, and the zero-IF demodulator 13 of the first embodiment, which will not be repeated here. The zero-IF receiver 101 includes at least a zero-IF demodulator 13.

The zero-IF receiver 101 of this embodiment further includes a zero-IF modulator 14, the mixing circuit 12 includes a zero-IF modulator 14, the first input of the zero-IF modulator 14 is coupled to the output of the oscillator 11, The second input of the zero-IF modulator 14 receives the pulse signal, and the output of the zero-IF modulator 14 is coupled to the first input of the zero-IF demodulator 13.

The first input terminal of the zero intermediate frequency modulator 14 receives the local oscillator signal, and the second input terminal receives the pulse signal. The zero intermediate frequency modulator 14 amplitude-modulates the local oscillator signal according to the pulse signal to obtain a mixed signal; the zero intermediate frequency modulator 14 will mix The frequency signal is transmitted to the zero-IF demodulator 13, and in the zero-IF demodulator 13, the mixed signal is demodulated according to the local oscillator signal to obtain the channel gain.

Based on the first embodiment, in this embodiment, since the mixing circuit 12 includes a zero-IF modulator, directly calling the modulator of the zero-IF receiver can simplify the self-check circuit and reduce the size of the self-check circuit.

Please refer to FIG. 3, which is a schematic structural diagram of Embodiment 3 of a self-check circuit of the present application.

As shown in FIG. 3, the self-test circuit 200 disclosed in this embodiment includes at least an oscillator 21, a mixing circuit 22, a zero-IF demodulator 23 and an amplifier 24.

Among them, the first output terminal of the oscillator 21 is coupled to the input terminal of the mixing circuit 22, the output terminal of the mixing circuit 22 is coupled to the input terminal of the amplifier 24, and the output terminal of the amplifier 24 is connected to the The first input terminal is coupled, and the second output terminal of the oscillator 21 is further coupled to the second input terminal of the zero-IF demodulator 23.

The oscillator 21 generates a local oscillator signal, and the oscillator 21 outputs the local oscillator signal to the zero-IF demodulator 13 and the mixing circuit 22; the first input terminal of the mixing circuit 22 receives the local oscillator signal, and the second input terminal receives the pulse For signals, the mixing circuit 22 mixes the local oscillator signal and the pulse signal to generate a mixing signal; the amplifier 24 receives the mixing signal. Among them, different models of amplifiers 24 have different power gains. According to actual needs, the amplifier 24 with different power gains can be replaced in the self-test circuit 200; the amplifier performs power amplification processing on the mixed signal to generate an amplified signal and transmits it to zero IF Demodulator 23.

The first input terminal of the zero-IF demodulator 23 receives the amplified signal and the second input terminal receives the local oscillator signal; in the zero-IF demodulator 23, the amplified signal is demodulated according to the local oscillator signal to obtain the channel gain; wherein After the zero-IF demodulator 23 demodulates the amplified signal according to the local oscillator signal, a modulated signal is generated, and the modulated signal is an AC signal; the channel gain is the ratio between the modulated signal and the local oscillator signal.

Among them, the mixing circuit 22 includes a modulator (not shown in the figure), the modulator is an external device; when debugging the self-test circuit 200, different types of modulators can be added or replaced, which can be applied to local oscillator signals of different frequencies , So that the self-check circuit 200 has higher universality.

The mixing circuit 22 further includes an attenuator, and the modulator is an external device; compared to the external modulator and the zero-IF modulator in the first embodiment (not shown in the figure), the attenuator can better implement a self-check circuit The self-checking process of 200, the specific working principle is as follows: the local oscillator signal has a high-level signal and a low-level signal, and the attenuator can attenuate the high-level signal and the low-level information separately. The high-level signal is attenuated by the amount, and the attenuator attenuates the low-level signal by the second attenuation amount, thereby achieving a similar effect as a modulator.

In this embodiment, the mixing circuit 22 mixes the local oscillator signal and the pulse signal to obtain a mixed signal, and the amplified mixed signal is amplified by the amplifier 24 and transmitted to the zero-IF demodulator 23; the zero-IF demodulator 23 Demodulate the amplified signal according to the local oscillator signal to obtain an AC signal, and compare the ratio of the AC signal to the local oscillator signal to obtain the channel gain of the self-test circuit 200; since the signal in the self-test circuit 200 is demodulated After the AC signal is obtained, the AC signal will not be affected by the environment, such as temperature and other environmental factors, which can effectively improve the accuracy of the channel gain of the self-test circuit 200; since the mixing circuit 22 includes a modulator or attenuator, it can be based on Different parameters replace different modulators or attenuators to improve the universality of the self-check circuit 200.

Please refer to FIGS. 4-9. FIG. 4 is a schematic structural diagram of Embodiment 4 of a self-check circuit of the present application.

As shown in FIG. 4, the self-test circuit 300 disclosed in this embodiment at least includes an oscillator 31, a mixing circuit 32 and a zero-IF demodulator 33.

The first output of the oscillator 31 is coupled to the first input of the mixing circuit 32, the output of the mixing circuit 32 is coupled to the first input of the zero-IF demodulator 33, and the first An output terminal is further coupled to the second input terminal of the zero-IF demodulator 33.

The mixing circuit 32 includes an attenuator 321, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first diode D1, and a second diode D2.

The output of the attenuator 321 is connected to one end of the second resistor R2, one end of the first resistor R1 and the negative electrode of the first diode D1, and the other end of the second resistor R2 is grounded. The other end of the first resistor R1 is connected to one end of the third resistor R3, one end of the fourth resistor R4 and the first input end of the zero-IF demodulator 33, and the other end of the third resistor R3 is grounded , The other end of the fourth resistor R4 is connected to the cathode of the second diode D2, the anode of the first diode D1 and the anode of the second diode D2 and the fifth resistor R5 Is connected at one end, and the other end of the fifth resistor R5 receives the pulse signal.

The oscillator 31 generates a local oscillator signal, and the oscillator 31 outputs the local oscillator signal to the zero-IF demodulator 33 and the mixing circuit 32; the first input terminal of the mixing circuit 32 receives the local oscillator signal, and the second input terminal receives the pulse As for the signal, the mixing circuit 32 mixes the local oscillator signal and the pulse signal to generate a mixed signal.

Specifically, the pulse signal includes a first pulse signal and a second pulse signal, and the mixing signal includes a first mixing signal and a second mixing signal; the first pulse signal passes through the first diode D1 and the attenuated The vibration signal is mixed to obtain a first mixing signal, and the first pulse signal is grounded through the second resistor R2; the second pulse signal passes through the second diode D2 and the fourth resistor R4, and then A mixing signal is mixed to obtain a second mixing signal, and the second pulse signal is grounded through a third resistor R3.

Among them, the pulse signal includes a square wave signal, a triangle wave signal, a peak wave signal, and a step wave signal.

The first input terminal of the zero-IF demodulator 33 receives the second mixed signal, and the second input terminal receives the local oscillator signal; in the zero-IF demodulator 33, the second mixed signal is demodulated according to the local oscillator signal, In order to obtain the channel gain; wherein, the zero-IF demodulator 33 demodulates the second mixed signal according to the local oscillator signal to generate a modulated signal, the modulated signal is an AC signal; the channel gain is the difference between the modulated signal and the local oscillator signal ratio.

Among them, the AC signal includes an I channel signal and a Q channel signal, and the sum of the square of the amplitude difference of the I channel signal and the square of the amplitude difference of the Q channel signal is equal to the square of the amplitude difference of the AC signal. The amplitude of the I channel signal is the same as the amplitude of the Q channel signal, and the phase difference between the I channel signal and the Q channel signal is 90°.

For example, in this embodiment, the zero-IF demodulator 33 uses LT5506 with a gain range of 0 to 59dB. The LT5506 is controlled by the input voltage (0.2 to 1.7V) at the Vctrl terminal.

Among them, the power supply voltage of LT5506 is 3V, the frequency of the local oscillator signal fin = 284MHz; when the local oscillator signal is at a high level, Pin = -73dBm, when the local oscillator signal is at a low level, Pin = -79dBm; I and Q The differential load between R4=3.9kΩ.

When the input voltage Vctrl = 1.7V of the LT5506, the LO signal and the pulse signal are modulated to obtain a mixed signal, which is demodulated by the zero-IF demodulator 33 to obtain an AC signal. The AC signal includes an I-channel signal and a Q-channel signal. Refer to Figure 5 for the demodulated I channel signal waveform, and refer to Figure 6 for the demodulated Q channel signal waveform. As shown in FIGS. 5 and 6, _L V amplitude difference between the I and V _H is 130mV, _L Q channel amplitude difference between V _H and V is 100mV, the amplitude difference of the AC signal is

Thus, the channel gain of the self-test circuit 300 is calculated as:

It is obtained through actual measurement that the deviation between the measured value and the nominal value is -1.3 dB, which proves that the self-test circuit 300 in this embodiment has high self-test accuracy.

Please refer to FIG. 7 for the self-check principle diagram of the self-check circuit 300 in this embodiment. FIG. 7 is a schematic structural diagram of the self-check circuit principle in FIG. 4.

The self-check circuit 300 includes at least an oscillator 31, an attenuator 321, an amplifier 322, a first mixer 331, a second mixer 332, a phaser 333, a first low-pass filter 334, and a second low-pass filter 335 .

The first output of the oscillator 31 is coupled to the first input of the attenuator 321, the output of the attenuator 321 is coupled to the input of the amplifier 322, and the second output of the oscillator 31 is further coupled to the phaser 333 The input of the amplifier is connected; the output of the amplifier 322 is coupled to the first mixer 331 and the second mixer 332, the first mixer 331 is further coupled to the first low-pass filter 334, and the second mixer 332 is further coupled with the second low-pass filter 335.

The oscillator 31 generates a local oscillator signal, and the oscillator 31 outputs the local oscillator signal to the phaser 333 and the attenuator 321; the first input terminal of the attenuator 321 receives the local oscillator signal, the second input terminal receives the pulse signal, and the attenuator 321 Amplitude modulate the local oscillator signal and the pulse signal to generate a modulated signal and transmit it to the amplifier 322; after the amplifier 322 performs power amplification, the modulated signal is transmitted to the first mixer 331 and the second mixer 332; the first mixer The frequency mixer 331 mixes the modulation signal and the local oscillator signal, and obtains the I-channel signal through the first low-pass filter 334; the second mixer 332 mixes the modulation signal and the local oscillator signal and passes the second low The pass filter 335 obtains the Q channel signal.

Among them, the channel gain of the self-check circuit 300 is G, the local oscillator signal is cos(ω _c t), the amplitude waveform of the local oscillator signal can be seen in FIG. 8, and the modulated signal after amplitude modulation by the attenuator 321 and amplified by the amplifier 322 is a cos(ω _c t+θ); the final demodulated AC signal is

After the first low-pass filter 334, I channel signal is obtained:

The demodulated I and Q amplitude waveforms can be seen in Figure 9; the AC signal is

Therefore, the amplitude of the AC signal after demodulation is proportional to the channel gain, and the channel gain is calculated according to the amplitude value.

In the ADC's dynamic range, V _H and V _L, comparison with a threshold value, the channel gain G is determined to self-test circuit 300 is normal, the DC offset is not affected.

In this embodiment, since the signal in the self-test circuit 300 is demodulated, the AC signal is obtained. The AC signal is not affected by the environment, such as temperature and other environmental factors, which can effectively improve the accuracy of the channel gain of the self-test circuit 300. Sex.

The present application also provides a self-inspection device 400. For details, refer to FIG. 10, which is a schematic structural diagram of the self-inspection device of the present application.

The self-inspection device 400 is used to detect the channel gain of the zero-IF receiver. The self-inspection device 400 includes a driving power supply 41 and a self-inspection circuit 42. The self-inspection circuit 42 includes the above-described first embodiment, second embodiment, third embodiment, and implementation. The self-test circuit 100 in Example 4.

The present application also provides a receiver 500. For details, refer to FIG. 11, which is a schematic structural diagram of a receiver of the present application.

The receiver 500 includes the above-mentioned self-inspection device 51 and a radio frequency circuit 52. The radio frequency circuit 52 is coupled to the self-inspection device 51; the radio frequency circuit 52 is used to generate a radio frequency signal, and the self-inspection device 51 amplifies and outputs the radio frequency signal with a preset channel gain.

The self-inspection circuit, self-inspection device, and receiver provided in the embodiments of the present application are described in detail above. Specific examples are used in this article to explain the principles and implementation of the present application. The descriptions of the above embodiments are only for help Understand the methods and core ideas of this application; meanwhile, for those of ordinary skill in the art, according to the ideas of this application, there will be changes in the specific implementation and application scope. In summary, the content of this specification is not It should be understood as a limitation to this application.

Claims

A self-check circuit, wherein the self-check circuit is used to detect a channel gain of a zero-IF receiver, the zero-IF receiver includes at least a zero-IF demodulator, and the self-check circuit includes at least an oscillator and a mixing frequency Circuit; the first output of the oscillator is coupled to the first input of the mixing circuit, the output of the mixing circuit is coupled to the first input of the zero-IF demodulator, so The second output terminal of the oscillator is further coupled to the second input terminal of the zero-IF demodulator; wherein, the oscillator is used to generate a local oscillator signal, and the second input terminal of the mixing circuit is used to Receiving a pulse signal, mixing the local oscillator signal and the pulse signal to generate a mixed signal, and the zero-IF demodulator demodulates the mixed signal according to the local oscillator signal, The channel gain is obtained.
The self-check circuit according to claim 1, wherein the mixing circuit includes a zero-IF modulator, a first input terminal of the zero-IF modulator is coupled to a first output terminal of the oscillator, the The second input of the zero-IF modulator receives the pulse signal, and the output of the zero-IF modulator is coupled to the first input of the zero-IF demodulator.
The self-check circuit according to claim 1, wherein the self-check circuit further includes an amplifier, an input terminal of the amplifier is coupled to an output terminal of the mixing circuit, and an output terminal of the amplifier is connected to the zero The first input terminal of the intermediate frequency demodulator is coupled.
The self-check circuit according to claim 3, wherein the mixing circuit includes a modulator or an attenuator.
The self-test circuit according to claim 1, wherein the mixing circuit further includes an attenuator, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode, and a first Two diodes; the output of the attenuator is connected to one end of the second resistor, one end of the first resistor and the negative electrode of the first diode, and the other end of the second resistor is grounded, The other end of the first resistor is connected to one end of the third resistor, one end of the fourth resistor and the first input end of the zero-IF demodulator, the other end of the third resistor is grounded, the The other end of the fourth resistor is connected to the negative electrode of the second diode, the positive electrode of the first diode and the positive electrode of the second diode are connected to one end of the fifth resistor, the fifth The other end of the resistor receives the pulse signal.
The self-check circuit according to claim 1, wherein the pulse signal includes a square wave signal, a sawtooth wave signal, a triangle wave signal, a peak wave signal, and a step wave signal.
The self-test circuit according to claim 1, wherein the zero-IF demodulator outputs an AC signal, the AC signal includes an I-channel signal and a Q-channel signal, and the square of the amplitude difference between the I-channel signal and the Q The sum of the squares of the amplitude difference of the road signals is equal to the square of the amplitude difference of the AC signal.
The self-check circuit according to claim 7, wherein the amplitude of the I channel signal is the same as the amplitude of the Q channel signal, and the phase difference between the I channel signal and the Q channel signal is 90° .
A self-inspection device, wherein the self-inspection device is used to detect the channel gain of a zero-IF receiver; the self-inspection device includes a driving power supply and a self-inspection circuit, and the self-inspection circuit includes any of claims 1-8 One of the self-test circuits.
A receiver, wherein the receiver includes the self-test device according to claim 9; the receiver further includes a radio frequency circuit, the radio frequency circuit is coupled to the self-test device, and the radio frequency circuit is used for Input RF signal.