A high-isolation frequency distribution circuit and distribution method based on common-base amplification

Abstract

The application relates to a high-isolation frequency distribution circuit based on common-base amplification, which comprises a gain control amplifier, a distributor, a common-base amplification network and a filter; the gain control amplifier realizes gain control amplification of an input frequency signal and attenuated input to the distributor; the distributor realizes power distribution and isolation of the frequency signal without additional noise, and realizes multi-way output, each way of output being connected with a common-base amplification network; the common-base amplification network improves the reverse isolation characteristic of the frequency signal through the common-base triode current buffer characteristic, realizes high-isolation between multi-way output frequency signals and inputs the frequency signals to the filter; the filter suppresses the out-of-band noise of the frequency signal to reduce the harmonic and the out-of-band noise of the frequency signal. The application can realize amplification, distribution, isolation and filtering of low-noise frequency signals, improves the integration of the output frequency signal of the time-homogeneous equipment, and has the advantages of high isolation, low additional noise and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of low-noise frequency distribution technology, and in particular to a high-isolation frequency distribution circuit and a distribution method based on common-base amplification. BACKGROUND

[0002] Low-noise frequency distribution technology is widely used in high-precision timing equipment in the field of time-frequency synchronization. It can amplify, distribute and filter a low-noise frequency signal, realize one-to-many frequency signal distribution, and has the advantages of low additional noise. Isolation is a key technical index of frequency distribution devices, which represents the degree of power leakage between multiple frequency signals. Low isolation will directly lead to mutual interference between frequency signals, affecting the sensitivity of the downstream frequency system (such as radar system or receiver system). How to improve the isolation index is a problem that needs to be solved for current frequency distribution devices.

[0003] The basic methods for realizing the isolation index of current frequency distribution devices include two implementation schemes: using a passive power divider and using an operational amplifier isolator. The isolation scheme using a passive power divider has good low additional phase noise, but the isolation is low, about 30-40 dB, and the isolation will decrease with the increase of frequency. The isolation scheme using an operational amplifier isolator has the advantage of high isolation, which can reach 80 dB, but the thermal noise of the operational amplifier is high, resulting in a low noise of about -153 dBm, which is much higher than the low phase noise index (about -170 dBc / Hz@10 kHz) of the input frequency distribution device. Therefore, how to solve the coexistence of low noise and high isolation index of current frequency distribution devices, and realize the output frequency with low noise and high isolation characteristics is a problem that needs to be considered at this stage. SUMMARY

[0004] The present application aims to overcome the shortcomings of the current frequency distribution technology that low noise and high isolation cannot be met at the same time, and provides a high-isolation frequency distribution circuit based on common-base amplification, which solves the problems existing in current frequency distribution devices.

[0005] The purpose of the present application is achieved by the following technical scheme: a high-isolation frequency distribution circuit based on common-base amplification, which comprises a gain control amplifier, a distributor, a common-base amplification network and a filter. The gain control amplifier realizes gain control amplification and attenuation of the input frequency signal and inputs it to the distributor. The distributor realizes power distribution and isolation of the frequency signal without additional noise, and realizes multi-output, with each output connected to a common-base amplification network. The common-base amplification network improves the reverse isolation of the frequency signal through the common-base triode current buffer characteristic, realizes high isolation between the multi-output frequency signals, and inputs it to the filter. The filter suppresses the out-of-band noise of the frequency signal to reduce the harmonic and out-of-band noise of the frequency signal.

[0006] The common-base amplification network comprises a voltage-to-current circuit, a three-stage common-base amplification circuit, and an impedance matching and current-to-voltage circuit; the voltage-to-current circuit converts a voltage frequency signal into a small signal current frequency signal and inputs the signal into the three-stage common-base amplification circuit; the three-stage common-base amplification circuit controls the gain of the input current frequency signal and realizes reverse isolation, and then inputs the current signal into the impedance matching and current-to-voltage circuit; the impedance matching and current-to-voltage circuit realizes matching of impedance characteristics, reduces additional phase noise, converts the current signal into a voltage signal, and then inputs the voltage signal into the filter.

[0007] The three-stage common-base amplification circuit comprises transistors Q1, Q2 and Q3; the voltage-to-current circuit outputs a current frequency signal to the emitter of transistor Q3; the collector of transistor Q3 is connected to the emitter of transistor Q2; the collector of transistor Q2 is connected to the emitter of transistor Q1; the collector of transistor Q1 is connected to the impedance matching and current-to-voltage circuit; the bases of the three transistors are connected to ground through a capacitor; the signals transmitted between the three transistors are coupled and output through the common emitter; the shielding between the collector and the emitter is realized to reduce the capacitive coupling and achieve the purpose of reverse isolation.

[0008] The gain control amplifier comprises a first low-noise amplifier and a gain controller; the first low-noise amplifier amplifies the input signal and inputs the signal into the gain controller; the gain controller controls and amplifies the input frequency signal and then inputs the signal into the distributor.

[0009] The gain controller comprises a second low-noise amplifier and an attenuator; the first low-noise amplifier is connected to the second low-noise amplifier, and the second low-noise amplifier is connected to the attenuator; the combination of the second low-noise amplifier and the attenuator controls and amplifies the input frequency signal.

[0010] A high-isolation frequency distribution method based on common-base amplification, the frequency distribution method comprising:

[0011] Input a low-noise frequency signal f in into a gain control amplifier; realize attenuation configuration through a π-type resistance network to make the input signal frequency amplitude meet the linear range of the amplifier; adjust the attenuator to control and amplify the input frequency signal power according to the output frequency power requirement; output the amplified frequency signal f AMP ;

[0012] Distribute the frequency signal f AMP through a distributor to obtain multiple f DIV1 ...f DIVN frequency signals;

[0013] The multiple f DIV1 ...f DIVN Frequency signals are sequentially subjected to voltage-to-current, high-impedance buffer isolation, impedance matching and current-to-voltage processing to obtain f ISO1 ...f ISON Signals with high reverse isolation;

[0014] The f ISO1 ...f ISON Signals after high-isolation processing are respectively connected to the LC low-pass filter network at the back end to realize filtering processing of the out-of-band noise of f ISO1 ...f ISON Signals, and finally output f OUT1 ...f OUTN Frequency signals with high isolation and low additional phase noise.

[0015] The multiple f DIV1 ...f DIVN Frequency signals are sequentially subjected to voltage-to-current, high-impedance buffer isolation, impedance matching and current-to-voltage processing to obtain f ISO1 ...f ISON Signals with high reverse isolation, including:

[0016] The common-base amplification network first subjects f DIV1 ...f DIVN Signals to voltage-to-current processing through a voltage-to-current circuit to obtain the required current signals of the triode;

[0017] By using the current buffer characteristics of the common-base amplifier, the current signals are processed through a three-stage common-base amplification circuit to realize high-impedance buffer isolation of the input Signal and the output signal I out1 ...I outn ;

[0018] After the high-impedance buffer isolation of I out1 ...I outn Signals is realized, the signals are subjected to impedance matching processing through an impedance matching and current-to-voltage circuit to convert the current frequency signals into voltage frequency signals, and obtain f ISO1 ...f ISON Signals with high reverse isolation.

[0019] ​The application has the advantages that a high-isolation frequency distribution circuit based on common-base amplification can realize amplification, distribution, isolation and filtering of low-noise frequency signals, improves the integration of output frequency signals of time-honored devices, and has the advantages of high isolation (about 120 dB) and low additional noise. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a schematic diagram of the principle structure of the application;

[0021] Figure 2 It is a circuit schematic diagram of the common-base amplification network. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in combination with the drawings is not intended to limit the protection scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application. The present application will be further described below in combination with the drawings.

[0023] As Figure 1 shown, one embodiment of the present application relates to a high-isolation frequency distribution circuit based on common-base amplification, which comprises a gain control amplifier, a distributor, a common-base amplification network and a filter. The gain control amplifier realizes gain control amplification and attenuation of the input frequency signal and inputs the signal to the distributor. The distributor realizes power distribution and isolation of the frequency signal without additional noise and realizes multi-output, with each output connected to a common-base amplification network. The common-base amplification network improves the reverse isolation of the frequency signal through the common-base triode current buffer characteristic and realizes high-isolation between the multi-output frequency signals and inputs the signals to the filter. The filter suppresses the out-of-band noise of the frequency signal to reduce the harmonic and out-of-band noise of the frequency signal. The gain amplifier comprises a low-noise amplifier and a gain controller.

[0024] Further, the gain control amplifier is composed of a low-noise amplifier with excellent noise figure and a low-insertion-loss attenuator. The low-noise amplifier mainly realizes the amplification function of the signal, and the attenuator realizes the attenuation function of the amplified signal. Through the combination of the amplifier and the attenuator, the gain control amplification function of the input frequency signal can be realized.

[0025] The distributor adopts a passive power divider, can realize power distribution function without additional noise to frequency signals, realizes one-way input and multi-way output function, and the passive power divider has low noise characteristics and certain isolation characteristics.

[0026] The filter is a multi-order LC low-pass filter, can realize the suppression function of out-of-band noise of frequency signals, and can reduce the harmonic and out-of-band noise of frequency signals.

[0027] As shown in Figure 2 The common-base amplification network adopts a high-isolation circuit of a three-stage common-base high-frequency triode, which comprises a voltage-to-current circuit, a three-stage common-base amplification circuit, impedance matching and a current-to-voltage circuit, utilizes the current buffer characteristics of the common-base triode, improves the reverse isolation of frequency signals, and realizes the high-isolation function among multi-way output frequency signals. The voltage-to-current circuit realizes the function of converting voltage frequency signals into small-signal current frequency signals by a transformer coupling mode, and is used to solve the distortion problem caused by the nonlinearity of the input characteristics of the first-stage transistor.

[0028] The three-stage common-base amplification circuit is composed of three transistors and peripheral resistors and capacitors, can realize the gain control function of current signals, the transistors are grounded through resistors at the base, the transmission signals are coupled and output through common emitter stages, this method effectively forms a shield between the collector and the emitter, thereby reducing the capacitive coupling and realizing the reverse isolation function; the three-stage common-base amplification circuit receives the current signal of the voltage-to-current circuit, amplifies and processes the current signal through three-stage common-base amplification, and then outputs the processed current signal to the impedance matching and current-to-voltage circuit.

[0029] The impedance matching and current-to-voltage circuit are used to ensure the transmission quality of signals and the conversion of signal types, the impedance matching is used to match the impedance characteristics of the common-base amplification network and the current-to-voltage network, and reduce additional phase noise, and the current-to-voltage network is used to convert the current signal of the three-stage common-base amplification network into a voltage signal, and then input the processed voltage frequency signal to the filter network in the later stage.

[0030] Another embodiment of the present application relates to a high-isolation frequency distribution method based on common-base amplification, which comprises the following steps:

[0031] Step one: first, a high-precision time device low-noise frequency signal f inThe input gain-controlled amplifier employs a π-type resistor network for attenuation to meet the input range requirements, ensuring the input frequency amplitude remains within the amplifier's linear range. The input frequency signal is amplified by a low-noise amplifier to approximately 30dB. Then, the attenuation value of the attenuator is adjusted according to the user's output frequency power requirements (typically 6dBm) to achieve controlled amplification of the input frequency signal power, while maintaining extremely low noise figure characteristics. The final output is the amplified frequency signal f. AMP ;

[0032] Step 2: To achieve multi-output functionality, the frequency signal f after gain amplification in Step 1 needs to be... AMP By inputting a passive power divider network, which possesses extremely low added noise characteristics, it is possible to achieve f AMP Power allocation to obtain multiple f DIV1 ...f DIVN Frequency signals, and almost no noise is added to frequency signals;

[0033] Step 3: Allocate the power from the multiple channels in Step 2. DIV1 ...f DIVN The frequency signals are respectively input to the common-base amplifier network, and respectively affect f DIV1 ...f DIVN The signal undergoes voltage-to-current conversion to obtain the voltage required by the transistor. The current signal, utilizing the current buffer characteristic of the common-base amplifier, is processed through a three-stage common-base amplifier circuit to achieve the following: Signals and output signals I out1 ...I outn The high-impedance buffer isolation function, and then the I after achieving high-impedance buffer isolation out1 ...I outn After impedance matching, the signals are respectively obtained with high reverse isolation f ISO1 ...f ISON The signal ultimately improves f. ISO1 ...f ISON The signal isolation function has an isolation level better than 120dB, and the common-base amplifier network has the advantage of extremely low additional noise.

[0034] Step 4: After the high isolation process in Step 3, f ISO1 ...f ISON Each is connected to the back-end LC low-pass filter network to achieve f ISO1 ...f ISON The signal out-of-band noise filtering process results in a final output with high isolation and low additional phase noise. OUT1 ...fOUTN frequency signal, realizing the low noise amplification, distribution, high isolation processing and filtering processing of the frequency signal, and improving the isolation index of the frequency distribution technology. in frequency signal, realizing the low noise amplification, distribution, high isolation processing and filtering processing of the frequency signal, and improving the isolation index of the frequency distribution technology.

[0035] The above only describes the preferred embodiments of the present application, and it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concepts described herein by the above teachings or related art or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.

Claims

1. A high-isolation frequency distribution circuit based on common-base amplification, characterized by: It includes gain control amplifier, distributor, common base amplification network and filter; the gain control amplifier realizes gain control amplification of input frequency signal and attenuates and inputs to the distributor; the distributor realizes power distribution and isolation of frequency signal without additional noise, realizes output to each way, and each way output is connected with a common base amplification network; the common base amplification network improves reverse isolation of frequency signal through common base triode current buffer characteristic, realizes high isolation between multi-way output frequency signals and inputs to the filter; the filter suppresses the out-of-band noise of frequency signal to reduce the harmonic and out-of-band noise of frequency signal; The common base amplification network includes voltage-to-current circuit, three-stage common base amplification circuit and impedance matching and current-to-voltage circuit; the voltage-to-current circuit converts voltage frequency signal into small signal current frequency signal and inputs to the three-stage common base amplification circuit; the three-stage common base amplification circuit realizes gain control and reverse isolation of input current frequency signal and inputs current signal to the impedance matching and current-to-voltage circuit; the impedance matching and current-to-voltage circuit realizes matching of impedance characteristic, reduces additional phase noise, converts current signal into voltage signal and inputs to the filter; The three-stage common base amplification circuit includes transistors Q1, Q2 and Q3, the voltage-to-current circuit outputs current frequency signal to the emitter of transistor Q3, the collector of transistor Q3 is connected with the emitter of transistor Q2, the collector of transistor Q2 is connected with the emitter of transistor Q1, and the collector of transistor Q1 is connected with the impedance matching and current-to-voltage circuit; the bases of three transistors are connected with a capacitor and grounded, the transmission signals among three transistors are coupled and output through common emitter, shielding is formed between collector and emitter, and the purpose of reverse isolation is achieved by reducing capacitive coupling.

2. A high isolation frequency distribution circuit based on common-base amplification according to claim 1, characterized in that: The gain control amplifier includes first low noise amplifier and gain controller; the first low noise amplifier amplifies input signal and inputs to the gain controller; the gain controller realizes gain control amplification of input frequency signal and inputs to the distributor.

3. A high isolation frequency distribution circuit based on common-base amplification according to claim 2, characterized in that: The gain controller includes second low noise amplifier and attenuator; the first low noise amplifier is connected with the second low noise amplifier, the second low noise amplifier is connected with the attenuator, and the combination of second low noise amplifier and attenuator realizes gain control amplification of input frequency signal.

4. A high-isolation frequency division method based on common-base amplification, characterized by: The frequency distribution method includes: Input low noise frequency signal To gain control amplifier, through π type resistance network realizes attenuation configuration, makes input signal frequency amplitude satisfy amplifier linear range, according to the requirement of output frequency power, adjusts attenuator to control and amplify input frequency signal power, outputs amplified frequency signal ; distributing the frequency signals performing power distribution to obtain a plurality of ... frequency signals; Multiple channels are amplified by common base amplification network ... The frequency signal is sequentially processed by voltage to current, high resistance buffer isolation, impedance matching and current to voltage, and a high reverse isolation degree ... Signal; The high-isolation processed ... The signals are respectively connected to the LC low-pass filter network of the back end, realizing the filtering processing of the out-of-band noise of the signals ... The signals are respectively connected to the LC low-pass filter network of the back end, realizing the filtering processing of the out-of-band noise of the signals ... The signals are respectively connected to the LC low-pass filter network of the back end, realizing the filtering processing of the out-of-band noise of the signals The multiple channels of frequency signals are sequentially processed by voltage-to-current, high-impedance buffer isolation, impedance matching and current-to-voltage, and the frequency signals are obtained ... The frequency signals are sequentially processed by voltage-to-current, high-impedance buffer isolation, impedance matching and current-to-voltage, and the frequency signals are obtained ... The signals include: The common-base amplification network first converts the signals into current signals through a voltage-to-current circuit respectively ... ... which are required by the triode.​ The current signal is processed by three-stage common-base amplifier circuit using the current buffer characteristics of common-base amplifier to realize high resistance buffer isolation function of input signal and output signal respectively. ... signal and output signal ... ​ After the high-impedance buffer isolation is realized ... The current frequency signal is converted into a voltage frequency signal after the impedance matching and current-to-voltage circuit impedance matching processing, and a high-reverse isolation degree ... signal is obtained. The third-stage common-base amplifier circuit comprises transistors Q1, Q2 and Q3, the voltage-to-current circuit outputs a current frequency signal to the emitter of the transistor Q3, the collector of the transistor Q3 is connected with the emitter of the transistor Q2, the collector of the transistor Q2 is connected with the emitter of the transistor Q1, and the collector of the transistor Q1 is connected with the impedance matching and current-to-voltage circuit; the bases of the three transistors are connected with ground through a capacitor, and the transmission signals among the three transistors are coupled and output through the common emitter, so that the shielding between the collector and the emitter is formed, the capacitive coupling is reduced, and the purpose of reverse isolation is achieved.

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