CN112152578A - Modulation signal demodulation circuit, demodulation method and electronic equipment - Google Patents

Abstract

The invention discloses a modulation signal demodulation circuit, a demodulation method and electronic equipment, and relates to the technical field of electronic circuits to solve the problem of difficult detection of shallow modulation signals. The modulated signal demodulation circuit includes: an envelope detector and a dynamic bias control loop; the output end of the envelope detector is electrically connected to the input end of the dynamic bias control loop, and the dynamic bias control loop The output end of the device is electrically connected to the envelope detector; the envelope detector is used to detect and amplify the modulated signal to generate an envelope signal; the dynamic bias control loop is used to detect and amplify the modulation signal according to the envelope The signal generates a bias voltage for the envelope detector, wherein the bias voltage is used to control the envelope detector to stabilize at a static operating point when the modulation signal varies. The modulated signal demodulation circuit provided by the present invention is used for detecting shallow modulated signals.

Description

A modulated signal demodulation circuit, demodulation method and electronic device

technical field

The present invention relates to the technical field of electronic circuits, in particular to a modulated signal demodulation circuit, a demodulation method and electronic equipment.

Background technique

There is a problem of limited energy in the process of data transmission by wireless IoT nodes. In order to prolong the service life of the battery, wireless energy harvesting technology can be used to capture the RF signal energy in the surrounding environment and convert it into electrical energy to provide work for the load. required power supply voltage. This technology realizes both energy collection and demodulation from the same modulated signal received by the receiver, which reduces the use of off-chip components and saves the cost of the receiver. Traditional modulation signals such as binary on-off keying modulation, due to the large modulation depth, the signal power changes greatly, which is not conducive to energy transmission. Therefore, the amplitude modulation signal with shallow modulation can transmit energy and data at the same time.

The existing detectors have the following problems for shallow modulated signals: 1. Since the envelope change of the shallow modulated signal is small, it is difficult to detect the shallow modulated signal. 2. Since the amplitude of the input modulation signal is greatly affected by the environment, the traditional detector will change the static operating point of the transistor when the amplitude of the input modulation signal changes greatly, causing the signal to be distorted.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a modulated signal demodulation circuit, demodulation method and electronic equipment for detecting shallow modulated signals.

In a first aspect, the present invention provides a modulated signal demodulation circuit, the modulated signal demodulation circuit includes: an envelope detector and a dynamic bias control loop; an output end of the envelope detector is electrically connected to the dynamic an input end of a bias control loop, and an output end of the dynamic bias control loop is electrically connected to the envelope detector;

The envelope detector is used to detect and amplify the modulated signal to generate an envelope signal;

the dynamic bias control loop for generating a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used to control the envelope when the modulation signal changes The detector is stabilized at a static operating point.

Compared with the prior art, in the modulated signal demodulation circuit provided by the present invention, the output end of the envelope detector is electrically connected to the input end of the dynamic bias control loop, so that the envelope detector can be used for modulation of different depths. The signal is amplified and detected, and the dynamic bias control loop can generate the bias voltage of the envelope detector according to the envelope signal. However, because the amplitude of the input modulation signal will change, the envelope detector cannot work stably at the static operating point, and the output envelope signal will be distorted. Based on this, when the output terminal of the dynamic bias control loop is electrically connected to the envelope detector, the bias voltage output by the dynamic bias control loop is provided to the envelope detector, so that when the modulation signal changes, the envelope The envelope detector can be stabilized at the static operating point under the action of the bias voltage, so as to ensure that the output envelope signal is not distorted.

In a second aspect, the present invention also provides a modulated signal demodulation method, the modulated signal demodulation method comprising:

The envelope detector detects and amplifies the modulated signal to generate an envelope signal;

A dynamic bias control loop generates a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used to control the envelope detector to stabilize at a static operating point when the modulation signal changes .

Compared with the prior art, the beneficial effects of the modulated signal demodulation method provided by the embodiment of the present invention are the same as those provided by the above-mentioned modulated signal demodulation circuit, which will not be repeated here.

In a third aspect, the present invention also provides an electronic device, the electronic device comprising any of the above modulation signal demodulation circuits.

Compared with the prior art, the beneficial effects of the electronic device provided by the embodiments of the present invention are the same as those provided by the above-mentioned modulated signal demodulation circuit, which will not be repeated here.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

FIG. 1 illustrates a schematic structural diagram of an electronic device provided by an embodiment of the present invention;

FIG. 2 illustrates a simple structural schematic diagram of a modulation signal demodulation circuit provided by an embodiment of the present invention;

FIG. 3 illustrates a schematic diagram of a shallow modulation signal waveform provided by an embodiment of the present invention;

FIG. 4 illustrates a schematic structural diagram of a modulated signal demodulation circuit provided by an embodiment of the present invention;

FIG. 5 illustrates a schematic flowchart of a modulated signal demodulation method provided by an embodiment of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined. "Several" means one or more than one, unless expressly specifically defined otherwise.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. are based on those shown in the accompanying drawings The orientation or positional relationship is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; may be mechanical connection or electrical connection; may be direct connection or indirect connection through an intermediate medium, may be internal communication between two elements or an interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

FIG. 1 illustrates a schematic structural diagram of an electronic device provided by an embodiment of the present invention. As shown in FIG. 1 , an electronic device 110 provided by an embodiment of the present invention includes a modulated signal demodulation circuit 111 , a processor 112 , and a memory that communicates with the processor 112 . 113.

Wherein, the memory is used to store the program codes and data of the base station. The above-mentioned program codes and data are used to implement computer-executed instructions of the solutions of the present invention, and are controlled and executed by a processor. The processor is configured to execute the computer-executed instructions stored in the memory, thereby implementing the method provided by the embodiments of the present invention.

The memory can be read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM), or other types of static storage devices that can store information and instructions A dynamic storage device can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disk storage, optical disk storage (including compact disc, laser disc, compact disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage medium or other magnetic storage device, or capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer any other medium, but not limited to. The memory may exist independently and be connected to the processor through a communication line. The memory can also be integrated with the processor.

The processor may be a central processing unit (Central Processing Unit, CPU), a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application-Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logical blocks, modules and circuits described in connection with this disclosure. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

The above electronic device receives the modulated signal from the modulation device, obtains the envelope signal through the modulation and demodulation circuit, outputs the envelope signal to the processor for processing, and stores the final data obtained by processing in the memory. The above exemplifies an electronic device including a modulation signal demodulation circuit, but is not limited to this.

The process of demodulating a low-frequency signal from a modulated signal is called envelope detection. Envelope detection is amplitude detection. The commonly used method of envelope detection is to use diodes for unidirectional filtering and then low-pass filtering. Existing envelope detectors have difficulty in demodulating shallow modulated signals, and may not be able to detect successfully due to the shallow modulation depth. And when the amplitude of the modulated signal varies greatly, the detected envelope signal will be distorted.

In view of the above problems, embodiments of the present invention provide a modulated signal demodulation circuit. FIG. 2 illustrates a simple structural schematic diagram of a modulated signal demodulation circuit provided by an embodiment of the present invention. As shown in FIG. 2 , the above-mentioned modulated signal demodulation circuit 20 includes: an envelope detector 21 and a dynamic bias control loop 22; an envelope detector 21 and a dynamic bias control loop 22; The output end of the envelope detector 21 is electrically connected to the input end of the dynamic bias control loop 22 , and the output end of the dynamic bias control loop 22 is electrically connected to the envelope detector 21 .

The above envelope detector is used to detect and amplify the modulated signal to generate an envelope signal; the modulated signal here can be a deep modulated signal or a shallow modulated signal. For a shallow modulated signal, the process of detection is to amplify the demodulated signal while detecting, and the generated envelope signal is the amplified signal. The modulation depth refers to the ratio of the difference between the maximum amplitude and the minimum amplitude of the modulated wave to the sum of the maximum amplitude and the minimum amplitude of the carrier. In modulation technology, the modulation coefficient is a parameter to measure the modulation depth, and the modulation coefficient refers to the amplitude ratio of the modulation signal to the carrier signal. Formula (1) is the calculation formula of the amplitude modulation coefficient ma.

ma=[(A-B)/(A+B)]×100% (1)

A and B represent the maximum and minimum amplitudes in the vertical direction of the waveform, respectively.

FIG. 3 illustrates a schematic diagram of a shallow modulation signal waveform provided by an embodiment of the present invention. As shown in Figure 3, since the envelope change of the shallow modulation signal is very small, it needs to be amplified to detect it, and the output detection signal has a larger swing than it.

For the above reasons, the dynamic bias control loop is used to generate the bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used to control the envelope detector to stabilize at a static operating point when the modulation signal changes.

In practical applications, since the amplitude of the input signal of the envelope detector is greatly affected by the environment, the envelope detector needs to have a larger input dynamic range. The amplifier composed of transistors in the envelope detector should amplify the signal voltage without distortion, that is, set its static operating point. The dynamic bias control loop enables the bias voltage of the input envelope detector to change dynamically with the amplitude change of the modulating signal, so that the envelope detector still works at the static operating point when the input dynamic range is large. So that the detection is not distorted.

FIG. 4 illustrates a schematic structural diagram of a modulated signal demodulation circuit. As shown in FIG. 4 , the above-mentioned envelope detector includes: a first high-pass filter 211 , a second high-pass filter 212 , a differential amplifier 213 and a low-pass filter 214 .

As shown in FIG. 4 , the first input terminal of the differential amplifier 213 is electrically connected to the first high-pass filter 211 for accessing the modulation signal _VRF ; the second input terminal of the differential amplifier 213 is electrically connected to the first high-pass filter 211 for accessing the modulation signal _VRF The second high-pass filter 212 of the differential amplifier 213 is electrically connected; the first power supply terminal of the differential amplifier 213 is used to access the power supply voltage V _dd , and the second power supply terminal of the differential amplifier 213 is used for grounding; the output terminal of the differential amplifier 213 is connected to the dynamic bias control The input end of the loop is electrically connected; the input end of the dynamic bias control loop and the second power supply end of the differential amplifier 213 are both connected to the low-pass filter 214, and the output end of the dynamic bias control loop is respectively connected to the first high-pass filter The reference terminal of the filter 211 is electrically connected to the reference terminal of the second high-pass filter 212 .

The first high-pass filter and the second high-pass filter are respectively used for isolating the DC signal in the modulation signal, and coupling the modulation signal to the differential amplifier. The differential amplifier is used to amplify the modulated signal.

The differential amplifier 213 includes: a differential pair transistor 2131 and a load transistor 2132 .

The first control electrodes of the differential pair transistors are electrically connected to the output end of the first high-pass filter, and the second control electrodes of the differential transistors are electrically connected to the output end of the second high-pass filter.

The first electrode of the differential pair transistor is used to access the power supply voltage, the second electrode of the differential pair transistor is electrically connected to the second electrode of the load transistor; the second electrode of the load transistor is electrically connected to the input end of the dynamic bias control loop; The second electrode of the load transistor is also electrically connected to the input terminal of the low-pass filter, the ground terminal of the low-pass filter is electrically connected to the first electrode of the load transistor, and the ground terminal is grounded.

Differential pair of transistors used to amplify the modulated signal. The load transistor is used to keep the current magnitude of the modulated signal of the method constant, and output an envelope signal according to the demodulated signal from which the high-frequency signal is removed. The low-pass filter is used to process the amplified modulated signal to obtain the target signal. The differential amplifier is also used to generate the envelope signal from the target signal. The first high-pass filter and the second high-pass filter are respectively used to stabilize the envelope detector at a static operating point under the control of the bias voltage output by the dynamic bias control loop.

During specific operation, the first high-pass filter performs high-pass filtering on the modulated signal, isolates the DC signal in the modulated signal, and sends the obtained first filtered signal to the differential amplifier, and the second high-pass filter performs high-pass filtering on the modulated signal. , isolate the DC signal in the modulated signal, and send the obtained second filtered signal to the differential amplifier. The differential amplifier performs processing according to the first filtered signal and the second filtered signal to realize amplifying the modulated signal. At the same time, the low-pass filter processes the amplified modulation signal to obtain the target signal; the differential amplification generates the envelope signal according to the target signal, and sends it to the dynamic bias control loop. The bias voltage generated by the dynamic bias control loop can control the first high-pass filter and the second high-pass filter, so that the generated first and second filtered signals can smoothly enter the differential amplifier for amplification, and the differential amplifier is in the bias state. Under the action of the set voltage, it is stabilized at the static operating point, and the first filtered signal and the second filtered signal are amplified without distortion.

Exemplarily, as shown in FIG. 4, the first high-pass filter 211 includes: a first capacitor Cb1 and a first resistor Rb1; the second high-pass filter 212 includes: a second capacitor Cb2 and a second resistor Rb2; One end of the capacitor Cb1 that is electrically connected to the first input end of the differential amplifier 213 is the output end of the first high-pass filter 211 , and one end of the first capacitor Cb1 that is used to access the modulation signal is the input end of the first high-pass filter 211 , and the first resistor One end of Rb1 is also electrically connected to the first input end of the differential amplifier 213, and the other end is connected to the output end of the dynamic bias control loop. One end of the second capacitor Cb2 that is electrically connected to the second input end of the differential amplifier 213 is the output end of the second high-pass filter 212 , and one end of the second capacitor Cb2 that is used to access the modulation signal is the input end of the second high-pass filter 212 . One end of the two resistors Rb2 is also electrically connected to the first input end of the differential amplifier 213, and the other end is connected to the output end of the dynamic bias control loop.

As shown in FIG. 4 , the low-pass filter 214 includes: a third capacitor Co1 and a third resistor Ro1; the end of the third resistor Ro1 that is electrically connected to the input end of the dynamic bias loop is the input of the low-pass filter 214 The end of the third resistor Ro1 that is electrically connected to the control pole of the load transistor 2132 is the output end of the low-pass filter 214, and the output end of the low-pass filter 214 is also electrically connected to the first end of the third capacitor Co1. The second ends of the three resistors Ro1 are respectively electrically connected to the first electrodes of the load transistors 2132 and are all grounded.

The above-mentioned differential pair transistors include a first transistor and a second transistor, the first transistor and the second transistor are connected to each other, and the first electrode of the first transistor is electrically connected to the first electrode of the second transistor, and is respectively used to access the power supply voltage; The second electrode of a transistor is electrically connected to the second electrode of the second transistor, and is respectively connected to the second electrode of the load transistor, and the second electrode of the load transistor is electrically connected to the input end of the dynamic bias control loop; the first transistor The control electrode of the load transistor is electrically connected to the output end of the first high-pass filter, and the control electrode of the second transistor is electrically connected to the output end of the second high-pass filter; the second electrode of the load transistor is also connected to the input end of the low-pass filter. Electrical connection, the ground terminal of the low-pass filter is electrically connected to the first electrode of the load transistor, and the ground terminal is grounded.

When working specifically, the positive and negative poles of the modulating signal are connected to the input terminals of the first high-pass filter and the second high-pass filter, respectively. As shown in Figure 4, the high-pass filter adopts the simplest first-order high-pass filter. The signal enters the input terminals of the first capacitor Cb1 and the second capacitor Cb2. The modulated signal includes a DC signal and an AC signal, and the AC signal includes a low-frequency AC signal and a high-frequency AC signal. Characteristics, after the modulation signal passes through the first capacitor Cb1 and the second capacitor Cb2, only the AC signal in the modulation signal remains. In the differential amplifier, transistors with the same characteristics are connected, and the first high-pass filter and the second high-pass filter also have the same characteristics. The product of the first capacitor Cb1 and the first resistor Rb1 is taken as the first time constant. According to the first time constant Calculate the cut-off frequency of the first high-pass filter and the second high-pass filter, so that the AC signal above the cut-off frequency passes, and the first resistor Rb1 and the second resistor Rb2 attenuate the modulation signal passing through the first capacitor Cb1 and the second capacitor Cb2. AC signals below the cut-off frequency are prevented from passing through.

Specifically, as shown in FIG. 4 , the modulated signals output from the output terminals of the first capacitor Cb1 and the second capacitor Cb2 are modulated signals that isolate the DC signal and attenuate the AC signal below the cutoff frequency. The modulated signal is input to Control electrodes of the first and second transistors in the differential amplifier. According to the power supply voltage, the two input signals flow through the second electrodes of the first transistor and the second transistor respectively, and jointly flow into the load transistor, because the signal amplitudes of the control electrodes of the first transistor and the second transistor are the same and opposite in polarity, that is, The input signal is a differential mode signal. The output of the differential amplifier can be obtained according to the input signals V ⁺ _in , V ^- _in , the differential mode gain A _d and the common mode gain A _c of the differential amplifier. Formula (2) is the differential amplifier when the two inputs are differential mode signals. The calculation formula of the output value V _OUT :

V _OUT = A _d (V ⁺ _in –V ^- _in )+A _c (V ⁺ _in +V ^- _in )/2 (2)

Among them, V ⁺ _in and V ^- _in are the DC-isolated modulated signals output by the first high-pass filter and the second high-pass filter. Since the differential amplifier needs to increase the differential amplification factor and reduce the common-mode amplification factor, the As an approximate constant current circuit with large internal resistance, the load transistor replaces the commonly used resistance to reduce the common mode amplification. The two input signals V ⁺ _in and V ^- _in flow through the second electrodes of the first transistor and the second transistor respectively, and jointly flow into the input end of the third resistor Ro1 of the low-pass filter, the third resistor Ro1 and the third capacitor Co1 In series, the lower the input signal frequency, the larger the capacitive reactance of the third capacitor Co1, the higher the output voltage (the maximum does not exceed the input voltage); the higher the input signal frequency, the smaller the capacitive reactance of the third capacitor Co1, the output the lower the voltage. Take the product of the third capacitor Co1 and the third resistor Ro1 as the second time constant, and calculate the cutoff frequency of the low-pass filter according to the second time constant, so that the signal below the cutoff frequency passes through, and the resistance value of the third resistor Ro1 is constant , which attenuates the signal above the cutoff frequency and prevents it from passing. The signal output by the low-pass filter flows into the control electrode of the load transistor, so that the output terminal of the differential amplifier outputs an envelope signal that has amplified and filtered the high-frequency signal. The capacitor connected in parallel at the output end of the error amplifier adjusts the envelope signal to smoothly enter the first input end of the error amplifier, and the error amplifier dynamically obtains the envelope signal according to the envelope signal input at the first input end and the reference voltage of the peripheral input at the second input end. The bias voltage of the envelope detector is input to the reference terminals of the first high-pass filter and the second high-pass filter, so that when the amplitude of the modulating signal changes greatly, the first transistor and the second transistor in the envelope detector Work in the amplified state, that is, work at the static operating point, and output the envelope signal stably.

As an optional way, the dynamic bias control loop includes: an error amplifier and a grounded capacitor Ce;

As shown in FIG. 4 , the output terminal of the differential amplifier is electrically connected to the first input terminal of the error amplifier, the second input terminal of the error amplifier is used to connect to the reference voltage V _ref ; the output terminals of the error amplifier are respectively electrically connected to the first high-pass filter The reference terminal of the filter and the reference terminal of the second high-pass filter.

Error amplifier for generating the bias voltage for the envelope detector from the envelope signal and the reference voltage.

The capacitor is used to adjust the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal.

In practical applications, if the loop bandwidth of the dynamic bias control loop is greater than the baseband signal bandwidth of the envelope signal, the envelope signal cannot enter the error amplifier to generate the bias voltage.

As can be seen from the above, the modulated signal demodulation circuit provided by the present invention includes an envelope detector and a dynamic bias control loop. The envelope detector can amplify and detect modulated signals of different depths, especially the detection of shallow modulated signals. ; Since the amplitude of the input modulation signal will change, the envelope detector cannot work stably at the static operating point, and the output envelope signal will be distorted. After the envelope detector is connected to the dynamic bias control loop, Then, the bias voltage of the envelope detector can be generated according to the envelope signal output by the previous stage, and the dynamic control includes that the detector works at a static operating point, so that the output envelope signal is not distorted.

FIG. 5 illustrates a schematic flowchart of a modulated signal demodulation method provided by an embodiment of the present invention. An embodiment of the present invention also provides a modulated signal demodulation method, comprising the following steps:

Step 101: The envelope detector detects and amplifies the modulated signal to generate an envelope signal.

Step 102: The dynamic bias control loop generates a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used to control the envelope detector to stabilize at a static operating point when the modulation signal changes.

As an achievable manner, the above-mentioned envelope detector detects and amplifies the modulated signal, and the generation of the envelope signal includes:

The first high-pass filter and the second high-pass filter respectively isolate the DC signal in the modulation signal, and couple the modulation signal to the differential amplifier; the differential amplifier amplifies the modulation signal; the low-pass filter processes the amplified modulation signal to obtain the target signal; The differential amplifier also generates an envelope signal from the target signal. The first high-pass filter and the second high-pass filter are also under the control of the bias voltage output by the dynamic bias control loop, respectively, to stabilize the envelope detector at a static operating point.

Exemplarily, when the differential amplifier includes a differential pair transistor and a load transistor; the differential pair transistor amplifies the modulation signal; the load transistor keeps the current magnitude of the amplified modulation signal constant, and outputs an envelope signal according to the target signal.

In an optional manner, the dynamic bias control loop includes: an error amplifier and a grounded capacitor.

The error amplifier generates a bias voltage for the envelope detector based on the envelope signal and the reference voltage.

When the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal, the loop bandwidth of the capacitance-adjusted dynamic bias control loop is smaller than the baseband signal bandwidth of the envelope signal.

Compared with the prior art, the beneficial effects of the modulated signal demodulation method provided by the embodiment of the present invention are the same as those provided by the above-mentioned modulated signal demodulation circuit, which will not be repeated here.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are performed. The computer may be a general purpose computer, special purpose computer, computer network, terminal, user equipment, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program or instructions may be downloaded from a website site, computer, A server or data center transmits by wire or wireless to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that can be accessed by a computer, or a data storage device such as a server, data center, or the like that integrates one or more available media. The usable media may be magnetic media, such as floppy disks, hard disks, magnetic tapes; optical media, such as digital video discs (DVD); and semiconductor media, such as solid state drives (solid state drives). , SSD).

Although the invention is described herein in connection with various embodiments, in practicing the claimed invention, those skilled in the art can understand and implement the disclosure by reviewing the drawings, the disclosure, and the appended claims Other variations of the embodiment. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that these measures cannot be combined to advantage.

Although the invention has been described in conjunction with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention as defined by the appended claims, and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (9)

1. A modulated signal demodulation circuit, characterized in that the modulated signal demodulation circuit comprises: an envelope detector and a dynamic bias control loop; the output end of the envelope detector is electrically connected with the input end of the dynamic bias control loop, and the output end of the dynamic bias control loop is electrically connected with the envelope detector;

the envelope detector is used for detecting and amplifying the modulation signal to generate an envelope signal;

and the dynamic bias control loop is used for generating a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static operating point when the modulation signal changes.

2. The modulated signal demodulation circuit of claim 1 wherein the envelope detector comprises: the device comprises a first high-pass filter, a second high-pass filter, a differential amplifier and a low-pass filter;

the first input end of the differential amplifier is electrically connected with a first high-pass filter for accessing the modulation signal; the second input end of the differential amplifier is electrically connected with a second high-pass filter for accessing the modulation signal; the first power end of the differential amplifier is used for accessing a power supply voltage, and the second power end of the differential amplifier is used for grounding; the output end of the differential amplifier is electrically connected with the input end of the dynamic bias control loop;

the input end of the dynamic bias control loop and the second power supply end of the differential amplifier are both connected to the low-pass filter, and the output end of the dynamic bias control loop is respectively electrically connected with the reference end of the first high-pass filter and the reference end of the second high-pass filter;

the first high-pass filter and the second high-pass filter are respectively used for isolating direct current signals in the modulation signals and coupling the modulation signals to the differential amplifier;

the differential amplifier is used for amplifying the modulation signal;

the low-pass filter is used for processing the amplified modulation signal to obtain a target signal;

the differential amplifier is also used for generating an envelope signal according to the target signal;

the first high-pass filter and the second high-pass filter are respectively used for stabilizing the envelope detector at a static operating point under the control of the bias voltage output by the dynamic bias control loop.

3. The modulation signal demodulation circuit according to claim 2, wherein the differential amplifier comprises: a differential pair transistor and a load transistor;

the first control electrode of the differential pair transistor is electrically connected with the output end of the first high-pass filter, and the second control electrode of the differential transistor is electrically connected with the output end of the second high-pass filter;

the first electrode of the differential pair transistor is used for connecting a power supply voltage, and the second electrode of the differential pair transistor is electrically connected with the second electrode of the load transistor; a second electrode of the load transistor is electrically connected with an input end of the dynamic bias control loop; the second electrode of the load transistor is also electrically connected with the input end of the low-pass filter, the grounding end of the low-pass filter is electrically connected with the first electrode of the load transistor, and the grounding end is grounded;

the differential pair transistor is used for amplifying the modulation signal;

the load transistor is used for keeping the current of the amplified modulation signal constant and outputting the envelope signal according to the target signal.

4. The modulation signal demodulation circuit of claim 2 wherein the dynamic bias control loop comprises: an error amplifier and a grounded capacitor;

the output end of the differential amplifier is electrically connected with the first input end of the error amplifier, and the second input end of the error amplifier is used for accessing a reference voltage; the output end of the error amplifier is respectively and electrically connected with the reference end of the first high-pass filter and the reference end of the second high-pass filter;

the error amplifier is used for generating a bias voltage of the envelope detector according to the envelope signal and the reference voltage;

and the capacitor is used for adjusting the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal.

5. A modulated signal demodulation method, characterized by comprising:

the envelope detector detects and amplifies the modulation signal to generate an envelope signal;

and the dynamic bias control loop generates a bias voltage of an envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static working point when the modulation signal changes.

6. The method of claim 5, wherein the detecting and amplifying the modulated signal to generate the envelope signal comprises:

the first high-pass filter and the second high-pass filter respectively isolate direct current signals in the modulation signals and couple the modulation signals to the differential amplifier;

the differential amplifier amplifies the modulated signal;

the low-pass filter processes the amplified modulation signal to obtain a target signal;

the differential amplifier also generates an envelope signal according to the target signal;

and the first high-pass filter and the second high-pass filter respectively enable the envelope detector to be stabilized at a static working point under the control of the bias voltage output by the dynamic bias control loop.

7. The modulated signal demodulating method according to claim 6, wherein the differential amplifier includes: a differential pair transistor and a load transistor;

the differential pair of transistors amplifies the modulated signal;

the load transistor keeps the current magnitude of the amplified modulation signal constant, and outputs the envelope signal according to the target signal.

8. The method of claim 6, wherein the dynamic bias control loop comprises: an error amplifier and a grounded capacitor;

the error amplifier generates a bias voltage of the envelope detector according to the envelope signal and the reference voltage;

when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal, the capacitor adjusts the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal.

9. An electronic device, characterized in that the electronic device comprises the modulation signal demodulation circuit according to any one of claims 1 to 4.

Images