Frequency discrimination circuit and frequency discrimination method

Abstract

This disclosure provides one or more embodiments of a frequency discrimination circuit and a frequency discrimination method. The frequency discrimination circuit includes: a first frequency discrimination branch for receiving a radio frequency (RF) signal and performing a first amplitude detection on the RF signal, and outputting a first voltage signal positively correlated with the power of the RF signal; a second frequency discrimination branch for receiving the RF signal and performing low-pass filtering and a second amplitude detection on the RF signal, and outputting a second voltage signal positively correlated with the power of the RF signal and monotonically attenuating with the frequency of the RF signal; and a differential amplifier for receiving the first voltage signal and the second voltage signal and obtaining an output voltage based on the difference between the first voltage signal and the second voltage signal, wherein the output voltage is used to determine the input frequency of the RF signal.

Description

Technical Field

[0001] This disclosure relates to the field of integrated circuit technology, and more particularly to a frequency discrimination circuit and frequency discrimination method. Background Technology

[0002] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention.

[0003] With the continuous development of communication technology, the operating frequency bands of wireless communication base stations have expanded from below 2GHz to 6GHz, 28GHz, 39GHz, and even above 60GHz, and the instantaneous bandwidth has also expanded significantly. In order to ensure accurate frequency information in the closed-loop control processes of frequency hopping, beamforming, digital predistortion, real-time power calibration, and interference cancellation of wireless communication base stations, improving the detection accuracy and efficiency of carrier frequency has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the purpose of one or more embodiments of this disclosure is to provide a frequency discrimination circuit and frequency discrimination method to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, in a first aspect, this disclosure provides a frequency discrimination circuit, comprising:

[0006] The first frequency discrimination branch is used to receive the radio frequency signal and perform a first amplitude detection on the radio frequency signal, and output a first voltage signal that is positively correlated with the power of the radio frequency signal; The second frequency discrimination branch is used to receive the radio frequency signal and perform low-pass filtering and second amplitude detection on the radio frequency signal, and output a second voltage signal that is positively correlated with the power of the radio frequency signal and monotonically decays with the frequency of the radio frequency signal. A differential amplifier is used to receive the first voltage signal and the second voltage signal and obtain an output voltage based on the difference between the first voltage signal and the second voltage signal, the output voltage being used to determine the input frequency of the radio frequency signal.

[0007] Optionally, the first frequency discrimination branch includes a first amplitude detector; The second frequency discrimination branch includes a low-pass filter and a second amplitude detector; the first amplitude detector and the second amplitude detector have the same structure.

[0008] Optionally, the cutoff frequency of the low-pass filter is 0.5-0.8 times the lowest frequency of the measured frequency band.

[0009] Optionally, the low-pass filter is based on a first-order RC network, and the low-pass filter exhibits an attenuation characteristic of -20dB / dec within the measured frequency band.

[0010] Optionally, both the first amplitude detector and the second amplitude detector include: A common-source envelope detector is used to convert a received input signal into an envelope voltage. A low-pass filter capacitor is used to filter out the high-frequency ripple of the envelope voltage; A logarithmic amplifier is used to receive the envelope voltage after filtering out high-frequency ripple and output a DC voltage that is logarithmically related to the input signal.

[0011] Optionally, the common-source envelope detector includes a first field-effect transistor. Second field-effect transistor The low-pass filter capacitor includes a second capacitor. The logarithmic amplifier includes a third field-effect transistor. and feedback amplifier; Among them, the first field-effect transistor The gate and the first capacitor The first end is connected, the first capacitor The first end is also connected to the first resistor. The first resistor The second terminal is connected to the first bias voltage. The first capacitor Used to receive input signals; The first field-effect transistor The drain of the second capacitor First terminal, second field-effect transistor The source connection, the second capacitor The first terminal is also connected to the inverting input terminal of the feedback amplifier and the third field-effect transistor. The source; the second resistor The second terminal is grounded, and the non-inverting input terminal of the feedback amplifier is connected to the reference voltage. ; The first field-effect transistor The source is grounded; The second field-effect transistor The gate and the second bias voltage Connection, the second field-effect transistor The drain of the first power supply voltage connect; The third field-effect transistor The gate of the third field-effect transistor is connected to the output terminal of the feedback amplifier for outputting a voltage signal. The drain electrode is grounded.

[0012] Optionally, the differential amplifier is a differential input single-ended output amplifier.

[0013] Optionally, the differential amplifier includes a first P-channel field-effect transistor. Second P-channel MOSFET Third P-channel field-effect transistor Fourth P-channel field-effect transistor First N-channel field-effect transistor Second N-channel MOSFET Third N-channel field-effect transistor Third resistor Fourth resistor Fifth resistor Third capacitor Fourth capacitor Second power supply voltage and third bias voltage ; The first P-channel field-effect transistor The gate of the first P-channel MOSFET is used to receive the first voltage signal; The drain is connected to the first N-channel field-effect transistor. The drain of the third capacitor The first end and the third resistor The first terminal; the third capacitor The second terminal is grounded; The second P-channel field-effect transistor The gate of the second P-channel MOSFET is used to receive the second voltage signal; The drain of the second N-channel field-effect transistor is connected. The drain of the fourth capacitor The first end, the fourth resistor The first end, the fourth P-channel field-effect transistor The gate and the third N-channel field-effect transistor The gate of the fourth capacitor; The second terminal is grounded; The first N-channel field-effect transistor The gate is connected to the third resistor The second end, the fourth resistor The second end and the second N-channel field-effect transistor The gate of the first N-channel field-effect transistor; The source is grounded; the second N-channel MOSFET The source is grounded; The third P-channel field-effect transistor The gate is connected to the third bias voltage. The third P-channel field-effect transistor The source is connected to the second power supply voltage. The third P-channel field-effect transistor The drain of the first P-channel field-effect transistor is connected. The source and the second P-channel field-effect transistor The source pole; The fourth P-channel field-effect transistor The source is connected to the fifth resistor. The first end, the fourth P-channel field-effect transistor The drain of the third N-channel field-effect transistor is connected. The drain of the fifth resistor is used to output the differential voltage; The second terminal is connected to the second power supply voltage. ; The source of the third N-channel MOSFET MN3 is grounded.

[0014] A second aspect of this disclosure provides a frequency discrimination method, including: The radio frequency signal is subjected to a first amplitude detection to obtain a first voltage signal that is positively correlated with the power of the radio frequency signal; The radio frequency signal is subjected to low-pass filtering and second amplitude detection to obtain a second voltage signal that is positively correlated with the power of the radio frequency signal and monotonically decays with the frequency of the radio frequency signal. The output voltage is obtained based on the difference between the first voltage signal and the second voltage signal, and the output voltage is used to determine the input frequency of the signal.

[0015] Optionally, the first amplitude detection and the second amplitude detection processes are the same.

[0016] As can be seen from the above, the frequency discrimination circuit and method provided in this disclosure generate a first voltage signal positively correlated with the input power through a first amplitude detection by a first frequency discrimination branch, and generate a second voltage signal positively correlated with the input power and decaying with frequency through a second amplitude detection by a low-pass filter. The second voltage signal is then differentially processed using the first voltage signal as a reference voltage to eliminate the influence of the input power on the amplitude of the radio frequency signal, thereby effectively improving the accuracy and efficiency of frequency detection to a certain extent. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in one or more embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only one or more embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the frequency discrimination circuit of an exemplary embodiment of the present disclosure is shown; Figure 2 A schematic diagram of the structure of the first amplitude detector and the second amplitude detector of an exemplary embodiment of the present disclosure is shown; Figure 3 A schematic diagram of the structure of a differential amplifier according to an exemplary embodiment of the present disclosure is shown; Figure 4 A graph showing the output voltage of the frequency discrimination circuit as a function of input power in an exemplary embodiment of this disclosure is shown. Figure 5 The graphs showing the output voltage of the frequency discrimination circuit of the exemplary embodiment of the present disclosure as a function of frequency under different input powers are shown. Figure 6 A flowchart illustrating a frequency discrimination method according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0020] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] As described in the background section, with the continuous development of communication technology, how to improve the detection accuracy and efficiency of carrier frequency has become an urgent problem to be solved.

[0022] In some embodiments of this disclosure, the frequency of radio frequency signals can be detected by a slope-type frequency-to-voltage converter. The detection principle is as follows: the frequency of the radio frequency signal is mapped to different amplitudes based on the amplitude attenuation slope of a resistor-capacitor (RC) network or an inductor-capacitor (LC) network. Then, the radio frequency signal is converted into DC voltage according to the amplitude by an amplitude detector. In this way, the frequency detection is achieved by utilizing the mapping relationship between frequency and voltage.

[0023] While slope-type frequency-to-voltage converters (RF converters) offer the advantage of simple structure, their output is susceptible to the influence of the input power (amplitude) of the radio frequency (RF) signal. Specifically, the premise for RF signal frequency detection using a slope-type RF converter is that the input power of the RF signal remains constant. In this case, the output voltage of the slope-type RF converter has a linear relationship with the frequency of the RF signal, allowing frequency detection based on the output voltage. However, in reality, the input power (amplitude) of the RF signal may fluctuate. The output voltage of the RF signal is affected not only by the frequency of the RF signal but also by the input power. For example, RF signals with the same input power (amplitude) but different frequencies may produce different output voltages through a slope-type RF converter, and RF signals with different input power (amplitude) but the same frequency may also produce different output voltages. In such cases, the frequency of the RF signal cannot be accurately detected using a slope-type RF converter.

[0024] In view of the above, embodiments of this disclosure provide a frequency discrimination circuit, characterized in that it includes: a first frequency discrimination branch, used to receive a radio frequency signal and perform a first amplitude detection on the radio frequency signal, and output a first voltage signal positively correlated with the power of the radio frequency signal; a second frequency discrimination branch, used to receive the radio frequency signal and perform low-pass filtering and second amplitude detection on the radio frequency signal, and output a second voltage signal positively correlated with the power of the radio frequency signal and monotonically attenuating with the frequency of the radio frequency signal; and a differential amplifier, used to receive the first voltage signal and the second voltage signal and output a voltage difference between the first voltage signal and the second voltage signal, wherein the voltage difference is used to determine the input frequency of the radio frequency signal.

[0025] Figure 1 A schematic diagram of the frequency discrimination circuit of an exemplary embodiment of the present disclosure is shown.

[0026] like Figure 1 As shown, the frequency discrimination circuit 100 of this embodiment includes: a first frequency discrimination branch 101, a second frequency discrimination branch 102, and a differential amplifier 103.

[0027] The first frequency discrimination branch 101 is used to receive the radio frequency signal and perform a first amplitude detection on the radio frequency signal. Optionally, the first frequency discrimination branch 101 may include a first amplitude detector 1011, which is used to receive the radio frequency signal and perform a first amplitude detection on the radio frequency signal. The first voltage signal output by the first frequency discrimination branch 101 is positively correlated with the power of the radio frequency signal.

[0028] The second frequency discriminator branch 102 is used to receive radio frequency (RF) signals and perform low-pass filtering and second amplitude detection on the RF signals. Optionally, the second frequency discriminator branch 102 may include a low-pass filter 1021 and a second amplitude detector 1022. The low-pass filter 1021 is used to receive RF signals and attenuate the power of RF signals of different frequencies. The second amplitude detector 102 is used to process the attenuated RF signals and map the attenuated power (amplitude) to a corresponding voltage. The second voltage signal output by the second frequency discriminator branch 102 is positively correlated with the power of the RF signal and attenuates monotonically with the frequency of the RF signal.

[0029] It should be noted that the output voltage of the amplitude detector (the first amplitude detector 1011 and the second amplitude detector 1022 in this disclosure) is linearly related to the input power of the input radio frequency signal, that is, the output voltage of the amplitude detector can be expressed as: ,in, Represents the correlation coefficient. This represents the input power of the input signal (e.g., a radio frequency signal). This indicates the relevant parameters.

[0030] It is understandable that the first voltage signal output by the first frequency discriminator branch 101 is... , can be represented as The second voltage signal output by the second frequency discriminator branch 102 This can be expressed as, ,in, This indicates that the input signal (e.g., radio frequency signal) undergoes frequency-dependent power attenuation after passing through the low-pass filter 1021. Obviously, this power attenuation is determined solely by the frequency of the input signal.

[0031] Thus, the result of the difference operation by the difference amplifier 103 can be expressed as: By using the first frequency discrimination branch 101 as a control group, the influence of the radio frequency signal input power (amplitude) is eliminated, ensuring more accurate frequency discrimination results.

[0032] In some embodiments, the low-pass filter 1021 can output a voltage signal that decreases (increases) monotonically as the input signal frequency increases. For example, the low-pass filter 1021 can exhibit an attenuation (amplification) characteristic of -20dB / dec as the input signal frequency increases within the measured frequency band.

[0033] Alternatively, the low-pass filter 1021 can be implemented based on a first-order filter network. For example, a first-order RC filter network.

[0034] In some embodiments, the cutoff frequencies of the first amplitude detector 1011 and the second amplitude detector 1022 are 0.5-0.8 times the lowest frequency of the measured frequency band to avoid the lowest frequency of the measured frequency band being close to the cutoff frequency, which would lead to unstable attenuation slope. In other words, it ensures that the entire measured frequency band maintains a certain degree of fixed attenuation (amplification) characteristics. For example, when the measured frequency band is 5-20 GHz, the cutoff frequencies of the first amplitude detector 1011 and the second amplitude detector 1022 can be 3.8 GHz.

[0035] On the other hand, it also ensures that the filter enters the passband flat region at the lowest frequency of the measured frequency band, with attenuation close to 0dB, so as not to damage the useful signal and avoid the frequency detector’s high-frequency bandwidth being limited due to the cutoff frequency being too low.

[0036] This disclosure does not limit the implementation method of the low-pass filter 1021 or the specific values ​​of its attenuation (amplification) characteristics.

[0037] Continue to refer to Figure 1 In some embodiments, the first amplitude detector 1011 of the first frequency discrimination branch 101 and the second amplitude detector 1022 of the second frequency discrimination branch 102 have the same structure to eliminate measurement deviations caused by inconsistent circuit structures, ensuring that the first amplitude detector 1011 and the second amplitude detector 1022 have consistent response characteristics to input signals (e.g., radio frequency signals) with the same input power, thereby ensuring to a certain extent that the first frequency discrimination branch 101 and the second frequency discrimination branch 102 have consistent response characteristics to radio frequency signals with the same input power, and the difference voltage between the first frequency discrimination branch 101 and the second frequency discrimination branch 102 is determined only by the frequency of the radio frequency signal.

[0038] Optionally, the first amplitude detector 1011 and the second amplitude detector 1022 can employ the same logarithmic detection structure. Exemplarily, both the first amplitude detector 1011 and the second amplitude detector 1022 can include: a common-source envelope detector, a low-pass filter capacitor, and a logarithmic amplifier based on source follower feedback (not shown in the figure). The common-source envelope detector converts the received input signal into an envelope voltage, and its output current is proportional to the squared average value Avg(Vin²) of the input voltage. The low-pass filter capacitor filters out high-frequency ripple in the envelope voltage. The output current of the common-source envelope detector follows a square law, and while outputting a DC level, a secondary voltage exists; the low-pass filter capacitor can filter out higher-order harmonics. The logarithmic amplifier receives the envelope voltage after filtering out high-frequency ripple and outputs a DC voltage that is logarithmically related to the input signal. It can utilize a method such as... Figure 2 The third field-effect transistor shown Logarithmic compression is achieved in the exponential relationship between drain current and gate-source voltage of (subthreshold field-effect transistor).

[0039] Reference Figure 2 In some embodiments, the common-source envelope detector may include a first field-effect transistor. Second field-effect transistor The low-pass filter capacitor includes a second capacitor. The logarithmic amplifier includes a third field-effect transistor. and feedback amplifier.

[0040] Among them, the first field-effect transistor The gate and the first capacitor The first end is connected to the first capacitor. The first end is also connected to the first resistor. First resistor The second terminal is connected to the first bias voltage. First capacitor Used to receive input signals; First field-effect transistor The drain and the second capacitor First terminal, second field-effect transistor The source connection, the second capacitor The first terminal is also connected to the inverting input of the feedback amplifier and the third field-effect transistor. The source; the second resistor The second terminal is grounded, and the non-inverting input of the feedback amplifier is connected to the reference voltage. First field-effect transistor The source is grounded; the second field-effect transistor The gate and the second bias voltage Connection, second field-effect transistor The drain of the first power supply voltage Connection; Third field-effect transistor The gate of the third field-effect transistor is connected to the output of the feedback amplifier to output a voltage signal. The drain electrode is grounded.

[0041] The first amplitude detector 1011 and the second amplitude detector 1022 achieve minimal power consumption while extending the dynamic range of the operating frequency band through the above-described direct detection architecture. Specifically, the first field-effect transistor... Second field-effect transistor This forms a common-source envelope detector, generating an input current proportional to the square of the input voltage, allowing this input current to flow into the third field-effect transistor of the feedback transistor without current loss. Third field-effect transistor Together with the feedback amplifier, they form a source-follower feedback-based logarithmic amplifier to achieve exponential VI conversion, thereby extending the dynamic range of the first amplitude detector 1011 and the second amplitude detector 1022 to over 40dB.

[0042] The differential amplifier 103 is used to perform differential processing after receiving the first voltage signal and the second voltage signal. Furthermore, the differential amplifier 103 can amplify a small DC level difference between the first voltage signal and the second voltage signal. That is, the differential amplifier 103 can obtain an output voltage based on the voltage difference, and the output voltage is used to determine the input frequency of the radio frequency signal.

[0043] In some embodiments, the differential amplifier 103 can be a differential input with a single-ended output.

[0044] Reference Figure 3 In some embodiments, the differential amplifier 103 may include a first P-channel field-effect transistor. Second P-channel MOSFET Third P-channel field-effect transistor Fourth P-channel field-effect transistor First N-channel field-effect transistor Second N-channel MOSFET Third N-channel field-effect transistor Third resistor Fourth resistor Fifth resistor Third capacitor Fourth capacitor Second power supply voltage and third bias voltage .

[0045] Among them, the first N-channel field-effect transistor Second N-channel MOSFET and its gate resistor (third resistor) Fourth resistor This constitutes the load of the differential pair. This self-biased active load not only provides high transimpedance gain, but also stabilizes the operating point through resistor feedback, improving the circuit's sensitivity to DC deviation.

[0046] Specifically, the first P-channel field-effect transistor The gate of the first P-channel field-effect transistor is used to receive the first voltage signal; The drain of the first N-channel field-effect transistor is connected. Drain, third capacitor First and third resistors The first terminal; the third capacitor The second terminal is grounded; the second P-channel MOSFET The gate of the second P-channel MOSFET is used to receive the second voltage signal; The drain of the second N-channel field-effect transistor is connected. Drain, fourth capacitor First terminal, fourth resistor First terminal, fourth P-channel field-effect transistor The gate and the third N-channel field-effect transistor The gate; the fourth capacitor The second terminal is grounded; the first N-channel MOSFET The gate is connected to the third resistor The second terminal and the fourth resistor The second terminal and the second N-channel field-effect transistor Gate; first N-channel field-effect transistor The source is grounded; the second N-channel MOSFET The source is grounded; the third P-channel MOSFET The gate is connected to the third bias voltage. Third P-channel MOSFET The source is connected to the second power supply voltage. Third P-channel MOSFET The drain of the first P-channel field-effect transistor is connected. The source and second P-channel field-effect transistor The source; the fourth P-channel MOSFET The source is connected to a five-resistor The first end, the fourth P-channel field-effect transistor The drain of the third N-channel field-effect transistor is connected. The drain of the fifth resistor is used to output differential voltage. The second terminal is connected to the second power supply voltage. The source of the third N-channel MOSFET MN3 is grounded.

[0047] The differential amplifier 103, through the architecture described in the above embodiment, achieves high gain and strong common-mode rejection. The specific working principle of the differential amplifier 103 is as follows: using a first P-channel field-effect transistor... Second P-channel field-effect transistor As a differential pair, with the first N-channel MOSFET Second N-channel field-effect transistor For constant current bias, through the third resistor and the fourth resistor The load converts the difference between the first voltage signal and the second voltage signal into a differential voltage.

[0048] To verify the technical effectiveness of the disclosed technical solution, the inventors also conducted performance tests.

[0049] Figure 4 A graph showing the output voltage of the frequency discrimination circuit of the present disclosure as a function of input power is shown.

[0050] Figure 4 The horizontal axis represents the input power (dBm), and the vertical axis represents the output voltage (V). This graph shows the output voltage curves of each node in the frequency discrimination circuit of this embodiment as a function of input power at a radio frequency signal frequency of 12 GHz. It can be seen that, with an input power range of -10 dBm to 10 dBm, the output voltage of the frequency discrimination circuit remains essentially unchanged with the input power, achieving a large dynamic range frequency discrimination of greater than 20 dB.

[0051] Figure 5 The diagram shows the output voltage of the frequency discrimination circuit of the exemplary embodiment of this disclosure as a function of frequency under different input powers.

[0052] Figure 5 The horizontal axis represents frequency (GHz), and the vertical axis represents output voltage (V). It can be seen that with an input power variation of -8dBm to 10dBm, the output voltage variation of the frequency discrimination circuit implemented in this disclosure is only 60mV.

[0053] Furthermore, the frequency discrimination circuit of this disclosure embodiment can also achieve frequency detection from 5 to 20 GHz. In other words, the frequency discrimination circuit of this disclosure embodiment also has the technical effects of wide bandwidth and large dynamic range.

[0054] Including the above, etc. Figure 1 , Figure 2 , Figure 3 The device with the structure shown can be used to achieve, for example Figure 6 The frequency discrimination method shown includes steps S601-S603: Step S601: Perform a first amplitude detection on the radio frequency signal to obtain a first voltage signal that is positively correlated with the power of the radio frequency signal; Step S602: Perform low-pass filtering and second amplitude detection on the radio frequency signal to obtain a second voltage signal that is positively correlated with the power of the radio frequency signal and monotonically decays with the frequency of the radio frequency signal; Step S603: Obtain the difference voltage based on the first voltage signal and the second voltage signal. The difference voltage is used to determine the input frequency of the radio frequency signal.

[0055] Optionally, the first amplitude detection and the second amplitude detection processes are the same.

[0056] The frequency discrimination method of this disclosure can achieve the same technical effect as the frequency discrimination circuit of this disclosure.

[0057] It should be noted that the methods of one or more embodiments of this disclosure can be executed by a single device, such as a computer or server. The methods of this embodiment can also be applied in a distributed scenario, where multiple devices cooperate to complete the process. In such a distributed scenario, one of these devices may execute only one or more steps of the methods of one or more embodiments of this disclosure, and the multiple devices will interact with each other to complete the method.

[0058] It should be noted that the above description pertains to specific embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than those shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0059] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this disclosure as described above, which are not provided in detail for the sake of brevity.

[0060] Additionally, to simplify the description and discussion, and to avoid obscuring one or more embodiments of this disclosure, the provided drawings may or may not show well-known power / ground connections to integrated circuit (IC) chips and other components. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring one or more embodiments of this disclosure, and this also takes into account the fact that the details of implementation of these block diagram apparatuses are highly dependent on the platform on which one or more embodiments of this disclosure will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuitry) are set forth to describe exemplary embodiments of this disclosure, it will be apparent to those skilled in the art that one or more embodiments of this disclosure may be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0061] Although this disclosure has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0062] This disclosure includes one or more embodiments intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A frequency discrimination circuit, characterized in that, include: The first frequency discrimination branch is used to receive the radio frequency signal and perform a first amplitude detection on the radio frequency signal, and output a first voltage signal that is positively correlated with the power of the radio frequency signal; The second frequency discrimination branch is used to receive the radio frequency signal and perform low-pass filtering and second amplitude detection on the radio frequency signal, and output a second voltage signal that is positively correlated with the power of the radio frequency signal and monotonically decays with the frequency of the radio frequency signal. A differential amplifier is used to receive the first voltage signal and the second voltage signal and obtain an output voltage based on the difference between the first voltage signal and the second voltage signal, the output voltage being used to determine the input frequency of the radio frequency signal.

2. The circuit according to claim 1, characterized in that, The first frequency discrimination branch includes a first amplitude detector; The second frequency discrimination branch includes a low-pass filter and a second amplitude detector; the first amplitude detector and the second amplitude detector have the same structure.

3. The circuit according to claim 2, characterized in that, The cutoff frequency of the low-pass filter is 0.5-0.8 times the lowest frequency of the measured frequency band.

4. The circuit according to claim 2, characterized in that, The low-pass filter is based on a first-order RC network and exhibits an attenuation characteristic of -20dB / dec within the measured frequency band.

5. The circuit according to claim 2, characterized in that, Both the first amplitude detector and the second amplitude detector include: A common-source envelope detector is used to convert a received input signal into an envelope voltage. A low-pass filter capacitor is used to filter out the high-frequency ripple of the envelope voltage; A logarithmic amplifier is used to receive the envelope voltage after filtering out high-frequency ripple and output a DC voltage that is logarithmically related to the input signal.

6. The circuit according to claim 5, characterized in that, The common-source envelope detector includes a first field-effect transistor. Second field-effect transistor The low-pass filter capacitor includes a second capacitor. The logarithmic amplifier includes a third field-effect transistor. and feedback amplifier; Among them, the first field-effect transistor The gate and the first capacitor The first end is connected, the first capacitor The first end is also connected to the first resistor. The first resistor The second terminal is connected to the first bias voltage. The first capacitor Used to receive input signals; The first field-effect transistor The drain of the second capacitor First terminal, second field-effect transistor The source connection, the second capacitor The first terminal is also connected to the inverting input terminal of the feedback amplifier and the third field-effect transistor. The source; the second resistor The second terminal is grounded, and the non-inverting input terminal of the feedback amplifier is connected to the reference voltage. ; The first field-effect transistor The source is grounded; The second field-effect transistor The gate and the second bias voltage Connection, the second field-effect transistor The drain of the first power supply voltage connect; The third field-effect transistor The gate of the third field-effect transistor is connected to the output terminal of the feedback amplifier for outputting a voltage signal. The drain electrode is grounded.

7. The circuit according to claim 1, characterized in that, The differential amplifier is a differential input single-ended output amplifier.

8. The circuit according to claim 7, characterized in that, The differential amplifier includes a first P-channel field-effect transistor. Second P-channel MOSFET Third P-channel field-effect transistor Fourth P-channel field-effect transistor First N-channel field-effect transistor Second N-channel MOSFET Third N-channel field-effect transistor Third resistor Fourth resistor Fifth resistor Third capacitor Fourth capacitor Second power supply voltage and third bias voltage ; The first P-channel field-effect transistor The gate of the first P-channel MOSFET is used to receive the first voltage signal; The drain is connected to the first N-channel field-effect transistor. The drain of the third capacitor The first end and the third resistor The first terminal; the third capacitor The second terminal is grounded; The second P-channel field-effect transistor The gate of the second P-channel MOSFET is used to receive the second voltage signal; The drain of the second N-channel field-effect transistor is connected. The drain of the fourth capacitor The first end, the fourth resistor The first end, the fourth P-channel field-effect transistor The gate and the third N-channel field-effect transistor The gate of the fourth capacitor; The second terminal is grounded; The first N-channel field-effect transistor The gate is connected to the third resistor The second end, the fourth resistor The second end and the second N-channel field-effect transistor The gate of the first N-channel field-effect transistor; The source is grounded; the second N-channel MOSFET The source is grounded; The third P-channel field-effect transistor The gate is connected to the third bias voltage. The third P-channel field-effect transistor The source is connected to the second power supply voltage. The third P-channel field-effect transistor The drain of the first P-channel field-effect transistor is connected. The source and the second P-channel field-effect transistor The source pole; The fourth P-channel field-effect transistor The source is connected to the fifth resistor. The first end, the fourth P-channel field-effect transistor The drain of the third N-channel field-effect transistor is connected. The drain of the fifth resistor is used to output the differential voltage; The second terminal is connected to the second power supply voltage. ; The source of the third N-channel MOSFET MN3 is grounded.

9. A frequency discrimination method, characterized in that, include: The radio frequency signal is subjected to a first amplitude detection to obtain a first voltage signal that is positively correlated with the power of the radio frequency signal; The radio frequency signal is subjected to low-pass filtering and second amplitude detection to obtain a second voltage signal that is positively correlated with the power of the radio frequency signal and monotonically decays with the frequency of the radio frequency signal. The output voltage is obtained based on the difference between the first voltage signal and the second voltage signal, and the output voltage is used to determine the input frequency of the signal.

10. The method according to claim 9, characterized in that, The processes for the first amplitude detection and the second amplitude detection are the same.

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