CN114362695B

CN114362695B - Information transmission system directly driven by AC small signal

Info

Publication number: CN114362695B
Application number: CN202210262307.3A
Authority: CN
Inventors: 补世荣; 罗宇; 陈柳; 谢沛臻
Original assignee: Yijiazi Chengdu Communication Co ltd
Current assignee: Yijiazi Chengdu Communication Co ltd
Priority date: 2022-03-17
Filing date: 2022-03-17
Publication date: 2022-05-24
Anticipated expiration: 2042-03-17
Also published as: CN114362695A

Abstract

The information transmission system directly driven by the AC small signal utilizes an AC power supply line to provide the AC small signal such as a power frequency signal to drive an oscillator, an amplifier and a mixer; the method comprises the steps of generating an output signal containing external physical quantity change information by using an oscillator, transmitting the output signal through a first transmitting antenna, receiving a signal transmitted by the first transmitting antenna by using a first receiving antenna, transmitting the signal to an amplifier for amplification, receiving the signal amplified by the amplifier by using a mixer, mixing the signal to generate a signal meeting the output frequency requirement, transmitting the signal by using a second transmitting antenna, and finally receiving the signal transmitted by the second transmitting antenna by using the second receiving antenna and transmitting the signal to a demodulation network to complete information demodulation. The microwave device realizes parametric amplification by using a resonant frequency-selecting network formed by connecting a parasitic capacitor of a transistor below a threshold voltage in series or in parallel with an inductor, so that the microwave device can be driven by an alternating current small signal, and various problems caused by the fact that the traditional microwave device needs direct current power supply are solved.

Description

Information transmission system directly driven by AC small signal

Technical Field

The invention belongs to the technical field of electronic power, the technical field of sensors and the field of information transmission, and relates to a system for carrying out information transmission by directly driving an alternating current small signal.

Background

The world has begun to enter the information age, and information plays an important role in various industries. The channels for people to obtain information in modern society are more and more extensive, besides traditional channels such as newspapers, radio and television, and the ways for people to obtain various information are continuously increased by the internet, mobile phones and the like, especially, the understanding of people on the importance degree of information is more and more popular and deep, the information monopoly is broken, and a large amount of information is shared by people. The way in which information is communicated is also varied. The main way and means by which people obtain information in the nature and production fields is through sensors. Sensors have long penetrated an extremely wide range of fields such as industrial production, space development, marine exploration, environmental protection, resource investigation, medical diagnosis, bioengineering, and even cultural relic protection. It is not an exaggeration to say that almost every modernization project is not separated from the various sensors.

The information acquired by the sensor can be transmitted in a wired or wireless mode, and wired transmission comprises telephone, fax, telegraph, television and the like; the wireless transmission can be realized by loading information on microwaves and transmitting the information through the microwaves. Such as the analog transmission and digital microwave transmission now used for transmitting video. The digital microwave transmission is to compress video codes, modulate the video codes through a digital microwave channel, and transmit the video codes through an antenna, wherein the receiving end receives signals, decompresses the signals through microwaves and restores analog video signals. The analog microwave transmission is that a video signal is directly modulated on a microwave channel and is transmitted out through an antenna, and a monitoring center receives the microwave signal through the antenna and then demodulates the original video signal through a microwave receiver. Effective information acquisition and information transmission have very important significance for daily life of residents, enterprise development and even national security.

The traditional microwave device realizes amplification based on a transistor, and the transistor needs a direct current power supply to supply power when working, but for the existing alternating current commercial power with the working frequency of 50Hz, the direct current power supply needed by electronic equipment needs to be obtained through various alternating current-direct current conversion, which brings energy conversion loss, and the conversion device also brings cost overhead.

Disclosure of Invention

Based on the defects of large energy waste and high cost caused by the fact that a microwave device in a traditional information transmission device needs direct current power supply, the invention designs an information transmission system based on the microwave device without direct current power supply, adopts alternating current to replace a direct current power supply for direct driving, and can realize driving when the amplitude of the alternating current is as low as 0.1V, so that the transmission system provided by the invention has the characteristics of direct alternating current driving, low energy consumption and wide application range.

In the information transmission system provided by the invention, the alternating current driving work of the microwave device is based on that the equivalent reactance of the transistor is driven in a time-varying manner by using an alternating current small signal (such as a power frequency signal) below the threshold voltage of the transistor, the time-varying driving can realize parametric amplification, the amplification work can be realized in a half power frequency period by using a single transistor, and the amplification work in a full power frequency period can be realized by using two transistors.

The invention adopts a technical scheme that a single transistor is adopted to realize a half-cycle power frequency direct drive information transmission system, and the technical scheme comprises the following steps:

the information transmission system directly driven by the alternating current small signal comprises an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in a half period of a working period of the alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna; the AC supply line provides the AC small signal for driving the oscillator, amplifier and mixer; the oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement, and then the signal is transmitted through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation;

the oscillator comprises a first transistor, a first inductor, a first feedback network, a first feed network and a first output frequency selection network, wherein a parasitic capacitor of the first transistor below a threshold voltage is connected with the first inductor in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the first transistor is set₁And inductance L of the first inductor₁Satisfy the requirement of

，

Setting the operating frequency of the first output frequency-selective network equal to the initial resonant angular frequency of the first feedback network

(ii) a The first feed network comprises a first high-pass branch and a first low-pass branch, one end of a drain electrode and a source electrode of the first transistor is connected with the ground level, and the other end of the first feed network outputs signals which are connected with the input end of the first feedback network and the input end of the first high-pass branch on one hand and signals output by the output end of the first low-pass branch on the other hand; the signal output by the output end of the first feedback network is connected with the grid electrode of the transistor; the input end of the first low-pass branch is connected with the alternating current small signal; the input end of the first output frequency-selecting network is connected with the output end of the first high-pass branch, and the output end of the first output frequency-selecting network generates an output signal of the oscillator; the resonance angular frequency of the first feedback network is related to the change of the external physical quantity, and the output signal of the oscillator contains the change information of the external physical quantity;

the amplifier comprises a second transistor, a second inductor, a first input frequency selection network, a second feed network and a second output frequency selection network, wherein the parasitic capacitance of the second transistor below a threshold voltage is connected with the second inductor in series or in parallel to form a resonant frequency selection network, and the capacitance C of the parasitic capacitance of the second transistor is set₂And inductance L of the second inductor₂Satisfy the requirement of

Setting the operating frequency of the first input frequency-selective network and the second output frequency-selective network equal to

，

Is the input signal angular frequency of the amplifier; the signal received by the first receiving antenna is used as an input signal of the amplifier and is connected to the input end of the first input frequency-selecting network, and the signal output by the output end of the first input frequency-selecting network is connected with the grid electrode of the second transistor; the second feed network comprises a second high-pass branch and a second low-pass branch, one end of the drain electrode and one end of the source electrode of the second transistor are connected with a ground signal, and the other end of the drain electrode and the source electrode of the second transistor output signals which are connected with the input end of the second high-pass branch on one hand and the output end of the second low-pass branch on the other hand; the input end of the second low-pass branch is connected with the alternating current small signal, the output end of the second high-pass branch is connected with the input end of the second output frequency-selecting network, and the output end of the second output frequency-selecting network generates an output signal of the amplifier;

the frequency mixer comprises a third transistor, a third inductor, a second input frequency selection network, a second feedback network, a third feed network and a third output frequency selection network, wherein the parasitic capacitance of the third transistor below a threshold voltage is connected with the third inductor in series or in parallel to form a resonant frequency selection network, and the capacitance C of the parasitic capacitance of the third transistor is set₃And inductance L of the third inductor₃Satisfy the requirement of

Setting the operating frequency of the third output frequency-selective network and the second feedback network to be equal to

，

The local oscillation signal angular frequency of the frequency mixer is obtained; the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the signal output by the output end of the second input frequency-selecting network is connected with the grid electrode of the third transistor, and the working frequency of the second input frequency-selecting network is set to be equal to the frequency of the output signal of the amplifier; the third feed network packetThe third feedback network comprises a third high-pass branch and a third low-pass branch, one end of a drain electrode and a source electrode of the third transistor is connected with the ground level, and the other end of the third transistor outputs signals which are connected with the input end of the second feedback network and the input end of the third high-pass branch on one hand and signals output by the output end of the third low-pass branch on the other hand; the signal output by the output end of the second feedback network is connected with the grid electrode of the third transistor; the input end of the third low-pass branch is connected with the alternating current small signal; the input end of the third output frequency-selecting network is connected with the output end of the third high-pass branch, and the output end of the third output frequency-selecting network generates an output signal of the frequency mixer.

Specifically, if the sources of the first transistor, the second transistor, and the third transistor are connected to a ground signal, the information transmission system operates in a positive half cycle of the duty cycle of the ac small signal; if the drains of the first transistor, the second transistor and the third transistor are connected to a ground signal, the information transmission system operates in a negative half period of the duty cycle of the alternating small signal.

Specifically, the first feedback network comprises a variable capacitor, a fourth inductor and a fifth inductor, the fourth inductor and the fifth inductor are connected in series and then connected in parallel with the variable capacitor between the input end and the output end of the first feedback network, and the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes along with the change of the external physical quantity;

the second feedback network comprises a first capacitor, a ninth inductor and a tenth inductor, the ninth inductor and the tenth inductor are connected in series and then are connected in parallel with the first capacitor between the input end and the output end of the second feedback network, and the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

Specifically, the first feedback network comprises a variable inductor, a second capacitor and a third capacitor, the second capacitor and the third capacitor are connected in series and then are connected in parallel with the variable inductor between the input end and the output end of the first feedback network, and the series point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes along with the change of the external physical quantity;

the second feedback network comprises a sixth inductor, a sixth capacitor and a seventh capacitor, the sixth capacitor and the seventh capacitor are connected in series and then are connected in parallel with the sixth inductor between the input end and the output end of the second feedback network, and the series point of the sixth capacitor and the seventh capacitor is grounded; the inductance value of the sixth inductor is a fixed value.

Specifically, the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch includes a seventh inductor and a fourth capacitor, one end of the seventh inductor is used as the input end of the first low-pass branch and is grounded through the fourth capacitor, and the other end of the seventh inductor is used as the output end of the first low-pass branch;

the first high-pass branch circuit, the second high-pass branch circuit and the third high-pass branch circuit are identical in structure, the first high-pass branch circuit comprises an eighth inductor and a fifth capacitor, one end of the fifth capacitor is used as the input end of the first high-pass branch circuit, and the other end of the fifth capacitor is used as the output end of the first high-pass branch circuit and is grounded after passing through the eighth inductor.

The invention adopts two transistors to realize the technical proposal that the full-period power frequency directly drives the information transmission system, and the technical proposal is as follows:

the information transmission system directly driven by the alternating current small signal comprises an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in the whole cycle of the working cycle of the alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna;

the AC supply line provides the AC small signal for driving the oscillator, amplifier and mixer; the oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement, and then the signal is transmitted through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation;

the oscillator comprises two oscillation units and a first power synthesizer, wherein the first power synthesizer is used for combining output signals of the two oscillation units into one signal and then taking the signal as an output signal of the oscillator;

each oscillating unit comprises a first transistor, a first inductor, a first feedback network, a first feed network and a first output frequency-selecting network, wherein the first feed network comprises a first high-pass branch and a first low-pass branch, and the grid of the first transistor is connected with a signal output by the output end of the first feedback network; the input end of the first low-pass branch is connected with the alternating current small signal; the input end of the first output frequency-selecting network is connected with the output end of the first high-pass branch, and the output end of the first output frequency-selecting network generates an output signal of the oscillating unit;

the first oscillating unit works in the positive half period of the working period of the alternating small signal, wherein the source electrode of the first transistor is connected with a ground signal; the drain electrode of the first transistor outputs a signal which is connected with the input end of the first high-pass branch and the input end of the first feedback network on one hand, and is connected with a signal output by the output end of the first low-pass branch on the other hand;

the second oscillation unit works in the negative half period of the working period of the alternating small signal, wherein the drain electrode of the first transistor is connected with a ground signal; the source electrode of the first transistor outputs a signal which is connected with the input end of the first high-pass branch and the input end of the first feedback network on one hand, and is connected with a signal output by the output end of the first low-pass branch on the other hand;

in each oscillation unit, a parasitic capacitor of a first transistor below a threshold voltage and a first inductor are connected in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the first transistor is set₁And inductance L of the first inductor₁Satisfy the requirement of

Setting the operating frequency of the first output frequency-selective network equal to

，

The initial resonance angular frequency of the first feedback network in the two oscillation units is the same, so that the resonance angular frequency of the first feedback network in the two oscillation units is related to the change of the same external physical quantity, and the output signal of the oscillator contains the change information of the external physical quantity;

the amplifier comprises a first power divider, a second power combiner and two amplifying units, wherein the first power divider is used for dividing signals received by the first receiving antenna into two signals and then respectively connecting the two signals to the input ends of the two amplifying units, and the second power combiner is used for combining the output signals of the two amplifying units into one signal and then using the signal as the output signal of the amplifier;

each amplifying unit comprises a second transistor, a second inductor, a first input frequency-selecting network, a second feed network and a second output frequency-selecting network, wherein the input end of the first input frequency-selecting network is used as the input end of the amplifying unit, and a signal output by the output end of the first input frequency-selecting network is connected with the grid electrode of the second transistor; the second feed network comprises a second high-pass branch and a second low-pass branch, the input end of the second low-pass branch is connected with the alternating current small signal, the output end of the second high-pass branch is connected with the input end of the second output frequency-selecting network, and the output end of the second output frequency-selecting network outputs the output signal of the amplifying unit;

the first amplifying unit works in the positive half period of the working period of the alternating small signal, wherein the source electrode of the second transistor is connected with a ground signal, and the drain electrode of the second transistor is connected with the signal output by the output end of the second high-pass branch on one hand and the signal output by the output end of the second low-pass branch on the other hand;

the second amplifying unit works in the negative half period of the working period of the alternating small signal, wherein the drain electrode of the second transistor is connected with a ground signal, and the source electrode of the second transistor is connected with the signal output by the output end of the second high-pass branch on one hand and the signal output by the output end of the second low-pass branch on the other hand;

in each amplifying unit, a parasitic capacitor of a second transistor below a threshold voltage is connected with a second inductor in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the second transistor is set₂And inductance L of the second inductor₂Satisfy the requirement of

，

Receiving an angular frequency of a signal for the first receive antenna;

the mixer comprises a second input frequency-selecting network, a second power divider, a third power synthesizer and two mixing units, wherein the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the output end of the second input frequency-selecting network is connected with the input end of the second power divider, and the working frequency of the second input frequency-selecting network is set to be equal to the frequency of the output signal of the amplifier; the second power divider is configured to divide a signal output by the second input frequency-selective network into two signals and then connect the two signals to input ends of the two frequency mixing units, and the third power combiner is configured to combine output signals of the two frequency mixing units into one signal and then use the signal as an output signal of the frequency mixer;

each frequency mixing unit comprises a third transistor, a third inductor, a second feedback network, a third feed network and a third output frequency selection network, wherein the third feed network comprises a third high-pass branch and a third low-pass branch, and a signal output by an output end of the second feedback network and a signal input by an input end of the frequency mixing unit are connected to a grid electrode of the third transistor; the input end of the third low-pass branch is connected with the alternating current small signal; the input end of the third output frequency-selecting network is connected with the output end of the third high-pass branch, and the output end of the third output frequency-selecting network generates an output signal of the frequency mixing unit;

the first frequency mixing unit works in a positive half period of the working period of the alternating current small signal, wherein the source electrode of a third transistor is connected with a ground signal, and the drain electrode of the third transistor outputs a signal which is connected with the input end of the third high-pass branch and the input end of the second feedback network on one hand and is connected with a signal output by the output end of the third low-pass branch on the other hand;

the second mixing unit works in the negative half period of the working period of the alternating current small signal, wherein the drain electrode of a third transistor is connected with a ground signal, and the source electrode of the third transistor outputs a signal which is connected with the input end of the third high-pass branch and the input end of the second feedback network on one hand and is connected with a signal output by the output end of the third low-pass branch on the other hand;

in each frequency mixing unit, a parasitic capacitor of a third transistor below a threshold voltage and a third inductor are connected in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the third transistor is set₃And inductance value L of the third inductor₃Satisfy the requirement of

，

Is the local oscillator signal angular frequency of the mixer.

The invention has the beneficial effects that:

firstly, the invention can drive the microwave device to work by directly utilizing the alternating current small signal and complete the pick-up and transmission of information, solves the problem of limitation caused by the requirement of a direct current power supply for driving the traditional information transmission system, and can be widely applied to various occasions.

Secondly, the invention utilizes the first feedback network to follow the change of the external physical quantity, thereby acquiring the change information of the external physical quantity and leading the oscillator to realize the information pickup function.

Moreover, the invention provides six schemes of forming a resonant frequency selection network by the transistor and the inductor, three schemes of working in a positive half period, a negative half period and a full period of the alternating current small signal, and two schemes of a feedback network, so that the invention has flexible application and wide application range.

Finally, the invention has no strict requirement on the magnitude of the driving voltage, and the information transmission system provided by the invention can work normally even if the power frequency driving voltage is smaller or the amplitude of the power frequency voltage serving as the bias is higher than the threshold voltage of the transistor.

Drawings

The following description of various embodiments of the invention may be better understood with reference to the following drawings, which schematically illustrate major features of some embodiments of the invention. These figures and examples provide some embodiments of the invention in a non-limiting, non-exhaustive manner.

Fig. 1 is a block diagram of an information transmission system directly driven by ac small signals according to the present invention.

Fig. 2 is a time varying capacitance/voltage curve in an amplified operation of a transistor. The circuit comprises a power frequency bias voltage indication circuit, a transistor gate-source capacitance time-varying characteristic in positive half-cycle working, a transistor gate-source capacitance time-varying characteristic in negative half-cycle working, a transistor drain-source capacitance time-varying characteristic in positive half-cycle working, and a transistor drain-source capacitance time-varying characteristic in negative half-cycle working.

Fig. 3 is a schematic structural diagram of an oscillator in which a gate-drain capacitor of a first transistor and a first inductor are connected in parallel to form a resonant frequency selection network, and the oscillator is directly driven by positive power frequency periodic power frequency based on a first feedback network with a first structure.

Fig. 4 is a schematic structural diagram of an oscillator in which a gate-drain capacitor of a first transistor and a first inductor are connected in parallel to form a resonant frequency selection network, and a first feedback network based on a first structure is used for realizing direct driving of an oscillator at a negative power frequency cycle.

Fig. 5 is a schematic structural diagram of an oscillator in which a gate-drain capacitor of a first transistor and a first inductor are connected in parallel to form a resonant frequency selection network, and the oscillator is directly driven by full power frequency cycle power frequency based on a first feedback network with a first structure.

Fig. 6 is a schematic structural diagram of an amplifier in which a gate-source capacitor of a second transistor and a second inductor are connected in parallel to form a resonant frequency-selective network, so that the amplifier is directly driven by positive power frequency cycle power frequency.

Fig. 7 is a schematic structural diagram of an amplifier in which a gate-source capacitor of a second transistor and a second inductor are connected in parallel to form a resonant frequency-selective network, so that the amplifier is directly driven by negative power frequency cycle power frequency.

Fig. 8 is a schematic structural diagram of an amplifier in which a gate-source capacitor of a second transistor and a second inductor are connected in parallel to form a resonant frequency-selective network, so that the amplifier is directly driven by full power frequency cycle power frequency.

Fig. 9 is a schematic structural diagram of a mixer in which a drain-source capacitor of a third transistor and a third inductor are connected in parallel to form a resonant frequency selection network, and a second feedback network based on a second structure is used to implement a positive power frequency period power frequency direct drive mixer.

Fig. 10 is a schematic structural diagram of a mixer in which a drain-source capacitor of a third transistor and a third inductor are connected in parallel to form a resonant frequency selection network, and a second feedback network based on a second structure is used to implement a negative power frequency cycle power frequency direct drive mixer.

Fig. 11 is a schematic structural diagram of a mixer in which a drain-source capacitor of a third transistor and a third inductor are connected in parallel to form a resonant frequency selection network, and a second feedback network based on a second structure is used to implement full-power-frequency-period power-frequency direct-drive mixer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the disclosed embodiments are merely exemplary of the invention, and are not intended to be exhaustive or exhaustive. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the information transmission system proposed by the present invention includes an ac power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna, and a demodulation network, wherein the ac power supply line is used to provide an ac small signal to drive the oscillator, the amplifier, and the mixer, and the ac small signal adopted by the present invention is required to have a frequency less than one tenth of the transmitting frequency of the system antenna, for example, a 50hz power frequency signal or other suitable signal can be used as a driving input. The oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement and then transmits the signal through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation.

The whole working process of the invention is as follows: the change of the external information causes the change of the resonant frequency of the first feedback network in the oscillator, so that the change information of the external physical quantity is loaded on the frequency of the electromagnetic wave output by the oscillator, the oscillator unit finishes the loading of the information, the electromagnetic wave loaded with the information is output by the oscillator and is transmitted to the space through the first transmitting antenna, and the first receiving antenna receives the electromagnetic wave transmitted by the first transmitting antenna and amplifies the electromagnetic wave through the amplifier. For frequency conversion relay, the signal amplified by the amplifier enters a mixer for mixing to obtain the frequency required by the later stage, and the electromagnetic wave signal output after frequency conversion by the mixer is transmitted through a second transmitting antenna. And the second receiving antenna receives the electromagnetic wave sent by the second transmitting antenna and sends the electromagnetic wave to a demodulation network to finish the demodulation of the information.

The microwave devices involved in the invention are all driven by small alternating current signals, and oscillators, amplifiers and mixers are realized based on parametric amplification of transistors, wherein the transistors are transistors capable of working in a radio frequency microwave frequency band, such as field effect transistors or other kinds of transistors meeting conditions. The invention uses transistor to realize parameter amplification, which is different from the prior transistor in that the pumping frequency of the prior parameter amplifier is about twice of the input signal frequency of the parametric amplification structure of the transistor, while the pumping frequency of the invention is greatly reduced, for example, the transistor can be driven to amplify at 50Hz power frequency. In fact, for a nonlinear device, when power is input at some specific frequency, the input power will be transferred to other newly generated frequency points to be output after nonlinear conversion, that is, the total input power and the total output power at all frequency points are conserved, without considering loss. In parametric amplifiers, this relationship is determined by the Menley equation (equations 1a and 1 b), where

The angular frequency of the input signal for the transistor parametric amplification structure,

for the angular frequency of the pump signal i.e. the ac small signal,

is at an angular frequency of

) M and n are the harmonic orders of the output signal of the parametric amplification structure of the transistor and the pump signal, respectively.

（1a）

（1b）

Taking an amplifier as an example, the strong nonlinear capacitance of the second transistor below the threshold voltage, i.e. the parasitic capacitance of the transistor (including the gate-drain capacitance C)_DGGate source capacitance C_GSDrain-source capacitance C_DS) And the second inductor form a resonant frequency-selecting network and make the capacitance value C of parasitic capacitance of the second transistor₂And inductance L of the second inductor₂Satisfy the requirement of

This will cause the circuit to operate at the signal frequency

And gain is arranged nearby, so that parametric amplification is realized under the power frequency bias condition by utilizing the nonlinear capacitance of the transistor.

The mixer and the oscillator are similar, the oscillator utilizes the parasitic capacitance of the first transistor below the threshold voltage to be connected with the first inductor in series or in parallel to form a resonant frequency selection network, and the capacitance value C of the parasitic capacitance of the first transistor is set₁And inductance L of the first inductor₁Satisfy the requirement of

Thereby realizing parametric amplification. The mixer utilizes the parasitic capacitance of the third transistor below the threshold voltage and the third inductor to form a resonant frequency selection network in series or in parallel, and the capacitance value C of the parasitic capacitance of the third transistor is set₃And inductance L of the third inductor₃Satisfy the requirement of

Realizing parametric amplification.

Parasitic capacitance of the transistor includes gate-drain capacitance C_DGGate source capacitance C_GSDrain-source capacitance C_DSThe gate-drain capacitance C of the first transistor of the oscillator is given as shown in FIGS. 3-5_DGA schematic diagram of a resonant frequency-selecting network formed by connecting the first inductor in parallel, wherein the first inductor is connected with the first inductor in parallelTwo ends of the inductor are respectively connected with the grid electrode and the drain electrode of the first transistor. In addition to this, the gate-drain capacitance C of the first transistor of the oscillator_DGThe resonant frequency-selecting network is formed by connecting the first inductor in series, and at this time, the drain electrode of the transistor is grounded or connected with the input end of the first high-pass branch circuit, the output end of the first low-pass branch circuit and the input end of the first feedback network after passing through the first inductor, and the series structure is not shown.

The gate-source capacitance C of the second transistor of the amplifier is given as shown in fig. 6-8_GSAnd the two ends of the second inductor are respectively connected with the grid electrode and the drain electrode of the second transistor. Besides, the grid source capacitance C of the second transistor of the amplifier can be used_GSAnd the grid of the second transistor is connected with the output end of the first input frequency-selecting network after passing through the second inductor.

The drain-source capacitance C of the third transistor of the mixer is shown in FIGS. 9-11_DSAnd the third inductor is connected in parallel to form a schematic diagram of a resonant frequency selection network, and two ends of the third inductor are respectively connected with the grid electrode and the drain electrode of the third transistor. Besides, the drain-source capacitance C of the third transistor of the mixer can be used_DSAnd the source electrode of the transistor is grounded or connected with the input end of the third high-pass branch circuit, the output end of the third low-pass branch circuit and the input end of the second feedback network after passing through the third inductor.

The transistors and inductors in the oscillator, amplifier, and mixer may be connected in the same or different manner, and may be interchanged with each other, for example, the first transistor and the first inductor of the oscillator are connected by the second transistor and the second inductor of the amplifier as shown in fig. 6-8, so that the gate-source capacitance C of the first transistor is connected by the gate-source capacitance C_GSThe first inductor and the second inductor form a resonant frequency-selecting network, so long as the parasitic capacitance of the transistor and the inductor are connected in series or in parallel to form the resonant frequency-selecting network. The traditional microwave device based on transistor for realizing amplification needs a direct current power supply, but the invention can drive the microwave device by utilizing an alternating current small signal, thereby solving the problem of energy of the traditional information transmission systemThe problem of loss of quantity.

The amplification can be realized in a half period (including a positive half period and a negative half period) of the alternating current small signal by using a single transistor, the amplification can be realized in a full period by using two transistors, three conditions of the positive half period, the negative half period and the full period are respectively explained below, and the alternating current small signal is explained by taking a 50Hz power frequency signal as an example in the embodiment.

In the case of an information transmission system operating in the positive half cycle, the oscillator has the structure shown in fig. 3, the amplifier has the structure shown in fig. 6, and the mixer has the structure shown in fig. 9, and the common point is that the source of the transistor is grounded and the drain is connected to the feed network. Under the drive of a sinusoidal bias voltage as shown in A in FIG. 2, when the bias voltage V is_DS≤V_tIn which V is_tWhen the capacitance/voltage characteristic between the drain and the gate of the transistor is shown as B in FIG. 2 and the capacitance/voltage characteristic between the drain and the source of the transistor is shown as D in FIG. 2 for the threshold voltage of the transistor, it can be seen that the gate-drain capacitance C of the transistor is shown as D in the positive half cycle of the bias voltage_DGGate source capacitance C_GSAnd a drain-source capacitor C_DSAll show strong non-linear changes. Therefore, in the case that the power frequency period shown by B, D in fig. 2 is close to the positive half cycle, the circuits shown in fig. 3, 6 and 9 can work in an amplification mode, so that the information transmission system shown in fig. 1 can work in the positive half cycle of the power frequency period.

In the case of an information transmission system operating in the negative half cycle, the oscillator has the structure shown in fig. 4, the amplifier has the structure shown in fig. 7, and the mixer has the structure shown in fig. 10, and the common point is that the drain of the transistor is grounded and the source is connected to the feed network. Under the drive of a sinusoidal bias voltage as shown in A in FIG. 2, when the bias voltage V is_DS≤V_tIn which V is_tWhen the capacitance/voltage characteristic between the drain and the gate of the transistor is shown as C in FIG. 2 and the capacitance/voltage characteristic between the drain and the source of the transistor is shown as E in FIG. 2 for the threshold voltage of the transistor, it can be seen that the gate-drain capacitance C of the transistor is shown as C in the negative half cycle of the bias voltage_DGGate source capacitance C_GSAnd a drain-source capacitor C_DSAll show strong non-linear changes. Thus C, E in FIG. 2The circuit shown in fig. 4, 7, 10 can work in an enlarged manner in the case where the power frequency cycle is close to the negative half cycle, so that the information transmission system shown in fig. 1 can work in the negative half cycle of the power frequency cycle.

In the case of full-cycle operation of the information transmission system, the oscillator has the structure shown in fig. 5, and includes an oscillation unit operating in the positive half cycle of the power frequency cycle and an oscillation unit operating in the negative half cycle of the power frequency cycle, and the output signals of the two oscillation units are synthesized by the first power synthesizer to obtain the output signal of the oscillator operating in the full cycle. Similarly, the amplifier has the structure shown in fig. 8, and the mixer has the structure shown in fig. 11. It should be noted that when V_DS≥V_tIn the circuits shown in fig. 5, 8 and 11, the transistors for realizing parametric amplification have the same circuit characteristics as the transistors for realizing reference amplification in the conventional circuits, which greatly improves the dynamic range of the parametric amplification circuits.

The working principles of the oscillator, amplifier and mixer are explained below.

The oscillator has the main function of loading information, and the working principle of the oscillator is as follows: at the moment of power-on, the transient current and the thermal noise current existing in the circuit contain rich harmonic components, the harmonic components are subjected to frequency selection through the first feedback network and are coupled and sent to the grid electrode of the first transistor for amplification, the amplified frequency components are subjected to frequency selection through the first feedback network and are coupled and sent to the grid electrode of the first transistor for re-amplification, and due to the nonlinearity of the transistor, the process cannot be continued all the time and finally tends to a stable state. The stabilized frequency signals can only flow out from the first high-pass branch of the first feed network through the first feed network, and the signals flowing out from the first high-pass branch are subjected to impedance matching by the first output frequency-selecting network and then are sent out. In the invention, the resonance angular frequency of the first feedback network is related to the change of the external physical quantity, so that the output signal of the oscillator contains the change information of the external physical quantity, specifically, due to the action of the first feedback network, the output end of the first feedback network can output a signal with a certain frequency, as shown in fig. 3-5, a variable capacitor is adopted to follow the change of the external physical information, when the variable capacitor changes along with the change of the external physical information, the frequency signal output by the first feedback network can change correspondingly, and thus, the information acquisition is completed. In some embodiments, the feedback network structure shown in fig. 9 to 11 may also be adopted, in which the inductance is changed into a variable inductance, so that the variable inductance is made to follow the change of the external physical information.

The main function of the amplifier is to amplify signals, and the working principle of the amplifier is as follows: an input signal of the amplifier is fed into a grid electrode of the second transistor after being subjected to impedance matching in a working frequency band through the first input frequency selection network (namely the grid electrode frequency selection network), then an input small signal is amplified in the second transistor, the amplified signal can only flow out from a second high-pass branch of the second feed network through the second feed network, a signal flowing out from the second high-pass branch is subjected to impedance matching through the second output frequency selection network (namely the drain electrode frequency selection network or the source electrode frequency selection network) and then is sent out of the amplifier, and meanwhile, the power frequency of the amplifier drives the second low-pass branch of the second feed network to be fed into the second transistor.

The main function of the frequency mixer is to complete frequency conversion relay transmission, and the working principle of the frequency mixer is as follows: at the moment of power-on, the instantaneous current and the thermal noise current existing in the circuit contain rich harmonic components, the harmonic components are subjected to frequency selection through the second feedback network and are coupled and sent to the grid electrode of the third transistor for amplification, the amplified frequency components are subjected to frequency selection through the second feedback network and are coupled and sent to the grid electrode of the third transistor for re-amplification, the process cannot be continued all the time due to nonlinearity of the transistors, and finally, the local oscillation signal of the mixer is formed when the local oscillation signal is in a stable state. On the other hand, the radio frequency signal input by the mixer is input to the grid electrode of the third transistor through the second input matching network, and after the radio frequency signal is mixed with the local oscillation signal returned by the second feedback network, a needed intermediate frequency signal is obtained at the drain electrode of the third transistor. The intermediate frequency signal can only flow out from a third high-pass branch of the third feed network through the third feed network, the signal flowing out from the third high-pass branch is subjected to impedance matching by a third output frequency-selecting network and then sent out of the frequency mixer, and meanwhile, a power frequency drive (in this embodiment, a 50Hz power frequency signal) of the frequency mixer is fed into a third transistor through a third low-pass branch of the third feed network.

In summary, the present invention provides three structures of a transistor gate-drain capacitance, a gate-source capacitance, a drain-source capacitance and an inductor in parallel connection to form a resonant frequency selection network, three structures of a transistor gate-drain capacitance, a gate-source capacitance, a drain-source capacitance and an inductor in series connection to form a resonant frequency selection network, and also provides two implementation structures for implementing a feedback network, and three structures of an information transmission system working in a power frequency positive half cycle, a power frequency negative half cycle and a full power frequency cycle, wherein six connection structures of a transistor parasitic capacitance and an inductor can be randomly arranged and combined with the two implementation structures of the feedback network, and can also be randomly arranged and combined with the three structures of the microwave device working in the power frequency positive half cycle, the power frequency negative half cycle and the full power frequency cycle, so that the information transmission system provided by the present invention can be directly driven by the power frequency, and can be widely applied to various occasions.

In addition, the invention has no strict requirement on the magnitude of the driving voltage, and by taking the structure shown in fig. 3 as an example, in the working process according to the embodiment shown in fig. 3, the invention finds that the circuit can also work in an amplifying way when the magnitude of the power frequency driving voltage is only 0.1V, and the voltage of 0.1V can be easily obtained on a power grid, thereby providing great convenience for the application of the information pickup circuit. Through the embodiment, the invention also finds that the transistor can realize amplification operation even if the power frequency voltage amplitude as the bias is higher than the threshold voltage of the transistor, and the transistor for realizing amplification in the circuit works in a normal amplification region with the bias voltage changed, so that the embodiment of fig. 3 can work in a wider bias voltage amplitude range.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The information transmission system is characterized by comprising an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in a half period of the working period of an alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna; the AC supply line provides the AC small signal for driving the oscillator, amplifier and mixer; the oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement, and then the signal is transmitted through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation;

，

，

Is the input signal angular frequency of the amplifier; the signal received by the first receiving antenna is used as an input signal of the amplifier and is connected to the input end of the first input frequency-selecting network, and the signal output by the output end of the first input frequency-selecting network is connected with the grid electrode of the second transistor; the second feed network comprises a second high-pass branch and a second high-pass branchOne end of the drain electrode and one end of the source electrode of the second transistor are connected with a ground signal, and the other end of the drain electrode and the source electrode of the second transistor are connected with an input end of the second high-pass branch on one hand and a signal output by an output end of the second low-pass branch on the other hand; the input end of the second low-pass branch is connected with the alternating current small signal, the output end of the second high-pass branch is connected with the input end of the second output frequency-selecting network, and the output end of the second output frequency-selecting network generates the output signal of the amplifier;

，

The local oscillation signal angular frequency of the frequency mixer is obtained; the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the signal output by the output end of the second input frequency-selecting network is connected with the grid electrode of the third transistor, and the working frequency of the second input frequency-selecting network is set to be equal to the frequency of the output signal of the amplifier; the third feed network comprises a third high-pass branch and a third low-pass branch, one of a drain electrode and a source electrode of the third transistor is connected with the ground level, and the other end of the third feed network outputs signals which are connected with the input end of the second feedback network and the input end of the third high-pass branch on the one hand and connected with the signals output by the output end of the third low-pass branch on the other hand; the signal output by the output end of the second feedback network is connected with the stationA gate of the third transistor; the input end of the third low-pass branch is connected with the alternating current small signal; the input end of the third output frequency-selecting network is connected with the output end of the third high-pass branch, and the output end of the third output frequency-selecting network generates an output signal of the frequency mixer.

2. The information transmission system directly driven by the alternating current small signal according to claim 1, wherein if the sources of the first transistor, the second transistor and the third transistor are connected to a ground signal, the information transmission system operates in a positive half period of the duty cycle of the alternating current small signal; and if the drains of the first transistor, the second transistor and the third transistor are connected with a ground signal, the information transmission system works in a negative half period of the working cycle of the alternating small signal.

3. The information transmission system directly driven by the alternating current small signals as claimed in claim 1 or 2, wherein the first feedback network comprises a variable capacitor, a fourth inductor and a fifth inductor, the fourth inductor and the fifth inductor are connected in series and then connected in parallel with the variable capacitor between the input end and the output end of the first feedback network, and the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes along with the change of the external physical quantity;

4. The information transmission system directly driven by the alternating current small signals as claimed in claim 1 or 2, wherein the first feedback network comprises a variable inductor, a second capacitor and a third capacitor, the second capacitor and the third capacitor are connected in series and then connected in parallel with the variable inductor between the input end and the output end of the first feedback network, and the series connection point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes along with the change of the external physical quantity;

5. The information transmission system directly driven by small alternating current signals according to claim 1, wherein the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch comprises a seventh inductor and a fourth capacitor, one end of the seventh inductor is used as an input end of the first low-pass branch and is grounded through the fourth capacitor, and the other end of the seventh inductor is used as an output end of the first low-pass branch;

6. The information transmission system is characterized by comprising an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in the whole period of the working period of the alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna;

，

the second amplifying unit works in the negative half period of the working cycle of the alternating current small signal, wherein the drain electrode of the second transistor is connected with a ground signal, and the source electrode of the second transistor is connected with the output signal of the second high-pass branch on one hand and the signal output by the output end of the second low-pass branch on the other hand;

in each amplifying unit, a parasitic capacitor of a second transistor below a threshold voltage is connected in series or in parallel with a second inductor to form a resonant frequency-selecting network, and a capacitance value C of the parasitic capacitor of the second transistor is set₂And inductance L of the second inductor₂Satisfy the requirement of

，

Receiving an angular frequency of a signal for the first receive antenna;

the mixer comprises a second input frequency-selecting network, a second power divider, a third power synthesizer and two mixing units, wherein the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the output end of the second input frequency-selecting network is connected with the input end of the second power divider, and the working frequency of the second input frequency-selecting network is set to be as close to the frequency of the output signal of the amplifier as possible; the second power divider is configured to divide a signal output by the second input frequency-selective network into two signals and then respectively connect the two signals to input ends of the two frequency mixing units, and the third power combiner is configured to combine output signals of the two frequency mixing units into one signal and then use the signal as an output signal of the frequency mixer;

the first frequency mixing unit works in the positive half period of the working period of the alternating current small signal, wherein the source electrode of a third transistor is connected with a ground signal, and the drain electrode of the third transistor outputs a signal which is connected with the input end of the third high-pass branch and the input end of the second feedback network on one hand and is connected with a signal output by the output end of the third low-pass branch on the other hand;

in each frequency mixing unit, a parasitic capacitor of a third transistor below a threshold voltage and a third inductor are connected in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the third transistor is set₃And inductance L of the third inductor₃Satisfy the requirement of

，

Is the local oscillator signal angular frequency of the mixer.

7. The information transmission system directly driven by alternating current small signals is characterized in that the first feedback network comprises a variable capacitor, a fourth inductor and a fifth inductor, the fourth inductor and the fifth inductor are connected in series and then connected in parallel with the variable capacitor between the input end and the output end of the first feedback network, and the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes along with the change of the external physical quantity;

the second feedback network comprises a first capacitor, a ninth inductor and a tenth inductor, the ninth inductor and the tenth inductor are connected in series and then connected in parallel with the first capacitor between the input end and the output end of the second feedback network, and the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

8. The information transmission system directly driven by alternating current small signals is characterized in that the first feedback network comprises a variable inductor, a second capacitor and a third capacitor, the second capacitor and the third capacitor are connected in series and then connected in parallel with the variable inductor between the input end and the output end of the first feedback network, and the series point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes along with the change of the external physical quantity;

9. The information transmission system directly driven by small alternating current signals according to any one of claims 6 to 8, wherein the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch includes a seventh inductor and a fourth capacitor, one end of the seventh inductor is used as the input end of the first low-pass branch and is grounded after passing through the fourth capacitor, and the other end of the seventh inductor is used as the output end of the first low-pass branch;