134 results about "Low gain" patented technology

In order to solve the problem that quick response and distortionless recording of ultrahigh-frequency partial discharge signals are difficult to realize when accidental pulses are generated in the prior art, the invention relates to a dual-channel parallel processing architecture for ultrahigh-frequency partial discharge signals, which comprises a signal cloning circuit and a signal processing circuit, the ultrahigh-frequency partial discharge module is used for receiving ultrahigh-frequency partial discharge signals and synchronously outputting the ultrahigh-frequency partial discharge signals as first target signals and second target signals after lossless copying; the low-gain channel circuit is used for performing buffer transmission for maintaining an original bandwidth and a dynamic range on the first target signal to generate a first gain signal; the high-gain channel circuit is used for performing gain amplification on the second target signal to generate a second gain signal; the digital signal processing unit is used for performing synchronous clock control on the low-gain channel circuit and the high-gain channel circuit; and the FPGA chip is integrated in the digital signal processing unit and is used for performing fusion splicing processing on the first gain signal and the second gain signal based on a waveform fusion splicing algorithm and generating a fusion signal.

The invention provides a wide-axial-ratio circularly polarized antenna, and relates to the technical field of antennas, and the antenna comprises a dielectric substrate, and the edge of the dielectric substrate is uniformly provided with metalized via holes; the radiation patch covers the upper surface of the dielectric substrate, and a first circular gap is formed in the middle of the radiation patch; the feed network is located on the lower surface of the dielectric substrate; the metal cover comprises a metal back cavity, the metal cover covers the bottom of the feed network and the bottom of the dielectric substrate, and the feed network is located in the metal back cavity; the radio frequency connector passes through the dielectric substrate and the radiation patch and is welded on the upper surface of the radiation patch; one end of the coaxial cable is connected to the lower end of the radio frequency connector, and the other end of the coaxial cable penetrates through the metal back cavity and is connected with the metal cover; the invention is used for solving the technical problems of low gain, narrow axial ratio beam width, complex design and manufacture and overlarge antenna size of the existing circularly polarized antenna.

The invention relates to the technical field of scatter communication, in particular to a narrow-edge traveling wave waveguide slot array antenna. Comprising an antenna housing which adopts a flanging design to protect an antenna surface; the slot radiation port is composed of a rectangular port array with horizontal short edges; the coupled feed port is composed of a rectangular port array with horizontal short edges; and the power division network is formed by cascading H-surface T-shaped power dividers and is formed by equally-divided and unequally-divided one-to-two power dividers. The problems that an existing panel antenna is low in gain, large in size and heavy in weight are solved.

The invention relates to the field of millimeter wave radars, and discloses a 45-degree polarized array waveguide antenna for a millimeter wave radar, which comprises a metal groove layer; a slot array element layer; the slot array element layer and the metal slot layer are connected in a vertical lamination mode; the metal groove layer is provided with a plurality of radiation grooves; radiation grooves with the same number are formed in the metal groove layer at the corresponding positions of the slot array elements; the radiation slot indirectly increases the effective radiation aperture area of the antenna. The invention provides a method for solving the problems of low array pattern sidelobe, low gain and wide beam width of the N-element waveguide array antenna in a miniaturized application scene.

The invention relates to the field of aeronautical material detection, and discloses an aeronautical material detection method and system.The method comprises the steps that an ultrasonic detection signal is obtained, and frequency characteristic analysis is conducted on the ultrasonic detection signal to obtain a frequency spectrum; based on the frequency spectrum, the system can judge the source information of the ultrasonic detection signals, so that the ultrasonic detection signals with background tendency and the ultrasonic detection signals with defect tendency are distinguished; aiming at signals from different sources, the invention innovatively adopts a differential gain processing strategy: low gain is applied to the signals with background tendency to effectively inhibit the intensity of the signals; high gain is applied to signals with defect tendency so as to ensure that even weak real defect signals can be fully amplified and identified; performing defect judgment on the ultrasonic detection signal subjected to gain processing; the problems that misjudgment is introduced by the signal gain compensation module due to probe sensitivity attenuation and normal background signals and real defect signals are difficult to distinguish can be effectively solved.

The present invention is applicable to the technical field of wireless communications, and in particular relates to a low-noise amplifier and a radio frequency chip. Compared with the prior art, the low-noise amplifier of the present invention comprises a signal input end, an input matching network, a first gain attenuation unit, a second gain attenuation unit, a power amplification unit, an output matching network, and a signal output end. In the second gain attenuation unit, a gate of a first switch transistor, a gate of a second switch transistor, a gate of a third switch transistor, and a gate of a fourth switch transistor are connected to an external logic control circuit, a source of the first switch transistor, a source of the second switch transistor, a source of the third switch transistor, and a source of the fourth switch transistor are respectively grounded, and a first end of a second inductor is connected to an input end of the power amplification unit. In this way, the low-noise amplifier of the present invention can give considerations to IIP3 and noise figure while the gain is reduced.

The invention provides a dual-conversion gain reading circuit, a reading method and an image sensor, and the circuit comprises a comparison module which carries out the pre-comparison of a high-gain photosensitive signal and a ramp signal, so as to obtain a pre-comparison result, comparing the low-gain reset signal, the high-gain reset signal, the high-gain photosensitive signal and the low-gain photosensitive signal with a ramp signal to output corresponding comparison signals; and the counting module selects a counting mode according to the pre-comparison result to count the comparison signals so as to output data signals. A comparison module is used for pre-comparing a high-gain photosensitive signal with a ramp signal, and a counting module is used for selecting a corresponding counting mode for counting quantization according to a pre-comparison result, so that the corresponding counting mode can be adaptively selected according to a voltage difference value between a high-gain reset signal and the high-gain photosensitive signal; therefore, the dynamic power consumption of the counting module is effectively reduced, the overall power consumption of the reading circuit is reduced, and the problem that an existing dual-conversion gain reading circuit is large in dynamic power consumption is solved.

The technology described herein is directed towards remotely controlling the direction and the signal strength of a beam reflected from a reconfigurable intelligent surface. A modular design of interconnected, communicatively coupled fundamental modules of unit cells facilitates a straightforward assembly process in which the aperture of the reconfigurable intelligent surface can be scaled by tiling together the modules. The reconfigurable intelligent surface aperture can be remotely fine-tuned with respect to gain and beam reflection direction upon receiving a control signal (e.g., a nine-bit digital code through infrared). Depending on a given scenario, the reflected beam be controlled to reflect an electromagnetic wave (e.g., mmWave) as a concentrated, high-gain coverage beam in a specified direction, a more expansive, low-gain coverage area beam in the specified direction, or something in between, e.g., medium signal strength and medium coverage area.

The invention provides a compensating circuit of a high-switching-frequency Buck converter and application of the compensating circuit, and belongs to the technical field of Buck converters. According to the compensating circuit, a high gain branch and a low gain branch are designed, wherein the branch including a first transconductance operational amplifier OTA1 has the characteristics of low gain and high bandwidth; the branches including the second transconductance operational amplifier OTA2 have the characteristics of high gain and low bandwidth, and the two branches are provided with corresponding active devices. A feedback voltage signal carrying switching noise is mainly introduced into a subsequent loop through two paths, the first loop passes through the first transconductance operational amplifier OTA1, the high-frequency gain of the path is extremely low, and the high-frequency gain of the switching noise can be effectively suppressed; and the second path passes through an advanced compensation module PD, a second transconductance operational amplifier OTA2 and a divider DIV to form current to charge a second capacitor C2, but the capacitor has an integral effect, so that the high-frequency gain of switching noise is effectively reduced. Compared with traditional three-type compensation, the method has higher noise suppression capability.

The application discloses a terahertz biological tissue imaging system and method based on a metasurface antenna. The terahertz biological tissue imaging system comprises a terahertz signal generator, an intelligent system control device, a terahertz signal transmitter and a data acquisition module. The terahertz signal generator is used for generating an ultra-wideband terahertz wave signal. The intelligent system control device controls the terahertz signal generator to continuously generate the ultra-wideband terahertz wave signal. The terahertz signal transmitter is used for transmitting the ultra-wideband terahertz wave signal after programmable modulation to a biological tissue organ. The terahertz signal receiver is used for receiving terahertz biological signals scattered inside and around the biological tissue organ, and modulating the received terahertz biological signals. The data acquisition module is used for acquiring the terahertz biological signals. The intelligent sensing signal processing module is used for processing the terahertz biological signals to obtain a terahertz image of the biological tissue organ. The application solves the problems of narrow bandwidth and low gain in the corresponding technology.

The present application provides an image sensor, a working method thereof, and an electronic device. A bit line module is provided, and in a first state, a low-gain reset signal is sampled into a first equivalent capacitor; in a second state, a high-gain reset signal and a high-gain image signal are sampled and outputted in sequence through a second gain output bit line; when the second state returns to the first state, the low-gain reset signal sampled in the first equivalent capacitor is outputted through the first gain output bit line, and then the low-gain image signal is sampled and outputted through the first gain output bit line; at the same time, a gain output selection circuit is connected to a matching readout circuit to achieve effective image quantization; while achieving a high dynamic range of the image sensor, the cost and size of the image sensor are reduced; because there is no need to sample and hold the output of the pixel circuit to reduce the KT / C noise of the circuit, the circuit noise level is lower, further improving the performance of the image sensor.

The on-off keying (OOK) receiver has a discontinuous automatic gain control (AGC) that sets the gain at the start of each frame and locks the gain setting for the remainder of that frame, preventing the OOK data from causing instability in the AGC loop. The AGC controller initializes the gain settings of the low-noise amplifier (LNA), low-pass filter (LPF), and programmable gain amplifier (PGA) to maximum values. The LNA, LPF, and PGA are in series and provide an input signal to the rectifier, which produces a voltage output to the 1 / 0 data decision circuit. The level detector compares the voltage output with two thresholds. When either threshold is exceeded, the AGC controller steps down the gain setting until the voltage output is between the two thresholds, at which point the gain setting is locked for the remainder of the current frame. When a long string of 0 data is detected between frames, the frame detector resets the AGC controller between frames. The LNA gain is reduced last.

The technology relates to enhanced time gated imaging in a manner that provides high dynamic range (HDR) functionality to a time gated pixel. An overflow path is provided for an integration node of a time-gated pixel, so that when the integration node saturates the excess charge flows to a low gain capacitor, creating readout signals from the integration node and the low gain capacitor, in order to obtain an HDR signal. A method includes modulating reset and transfer signals for an image sensor to selectively cause time-gated charge to accumulate in a photosensitive region of the image sensor, where the time-gated charge corresponds to a selected distance range. Then the charge is transferred to a charge storage region, and a saturated portion of the accumulated charge in stored a capacitor of the image sensor element. An HDR image is constructed from read-out of the charge storage region and the capacitor.

This invention relates to a pattern-reconfigurable antenna based on artificial surface plasmon polaritons (SSPPs), belonging to the field of antenna technology. The antenna includes a coplanar waveguide feed line, a transition structure, a reconfigurable SSPP waveguide, and periodic radiating elements. The reconfigurable SSPP waveguide modifies the dispersion characteristics by adding a varactor diode to a traditional SSPP element and adjusting the capacitance value using a bias circuit. The periodic radiating elements are elliptical patches with rectangular slots, coupled to the reconfigurable SSPP waveguide to radiate electromagnetic waves. This invention solves the problems of single radiation direction in traditional antennas and low gain in existing reconfigurable antennas. It achieves fixed-frequency beam scanning (maximum 23°) and frequency beam scanning (maximum 90°) in the 11.5GHz-15GHz frequency band, with gains greater than 9dBi (maximum 11.1dBi), expanding the detection range and increasing the detection distance, making it suitable for fields such as UAV detection.

The application discloses an image sensor readout circuit, an image sensor and a working method thereof, and belongs to the field of sensors. A switch selection circuit is connected with a pixel circuit of the image sensor. In a first state, a slope voltage is connected to a first node, and a reset signal and an image signal output by the pixel circuit under high conversion gain are connected to a second node in sequence. In a second state, the slope voltage and a coupling signal of the reset signal or the image signal output by the pixel circuit under low conversion gain are connected to the first node, and a reference voltage is connected to the second node. An analog-to-digital conversion circuit quantizes the high-gain reset signal and the high-gain image signal to obtain effective image signal quantization values under high gain, and quantizes the low-gain reset signal and the low-gain image signal to obtain effective image signal quantization values under low gain. While realizing high dynamic range of the image sensor, the cost is reduced and the volume is reduced.

The technology relates to enhanced time gated imaging in a manner that provides high dynamic range (HDR) functionality to a time gated pixel. An overflow path is provided for an integration node of a time-gated pixel, so that when the integration node saturates the excess charge flows to a low gain capacitor, creating readout signals from the integration node and the low gain capacitor, in order to obtain an HDR signal. A method includes modulating reset and transfer signals for an image sensor to selectively cause time-gated charge to accumulate in a photosensitive region of the image sensor, where the time-gated charge corresponds to a selected distance range. Then the charge is transferred to a charge storage region, and a saturated portion of the accumulated charge in stored a capacitor of the image sensor element. An HDR image is constructed from read-out of the charge storage region and the capacitor.

The invention relates to the field of integrated circuit design, in particular to a burst mode trans-impedance amplifier circuit for a 50G PON (Passive Optical Network), which comprises a high-frequency signal main circuit and a quick response auxiliary circuit, and the high-frequency signal main circuit realizes high-sensitivity amplification of low-optical-power signals and low-gain amplification of high-optical-power signals through the variable-gain transimpedance-stage amplification circuit and the amplitude-limiting post-stage amplification circuit. The quick response auxiliary circuit realizes ordered quick gain control and quick direct current bias elimination through a quick average value detection circuit controlled by different reset signals generated by the two circuits, and realizes quick response to burst signals together with the high-frequency signal main circuit. The device has the characteristics of high bandwidth, quick response and the like, can stably convert and amplify 50Gbps burst signals, and is suitable for a 50G PON uplink burst mode optical receiver system.

This invention provides a real-time hardware high dynamic range (HDR) synthesis method and camera with dual-gain grayscale characteristics, relating to the field of optical imaging technology. The method acquires dual-gain image data using a deployed sensor with high and low gain channels; performs noise suppression processing on the acquired dual-gain image data and non-uniformity correction to obtain preprocessed image data; fuses the high-gain and low-gain images into a HDR image through image fusion, and enhances the image signal-to-noise ratio and readout speed by merging adjacent pixels; verifies the dynamic range, image quality, and processing speed of the synthesized HDR image through actual shooting tests. This invention provides a dual-gain channel foundation for HDR synthesis by simultaneously outputting high-brightness and low-brightness images through the sensor's multi-gain channels. By synthesizing images with different gains, the dynamic range of the image can be significantly improved while maintaining image detail and quality.

The present invention discloses a C-band passively Q-switched pulsed fiber laser and a preparation method of a saturable absorber based on CsPbBr3 perovskite nanocrystals, belonging to the field of laser technology. The fiber laser is composed of a pump source, a wavelength division multiplexer, an erbium-doped gain fiber, an optical isolator, a saturable absorber based on a CsPbBr3 perovskite nanocrystal thin film, and a fiber output coupler connected in series end to end in sequence; in the present invention, the prepared CsPbBr3 perovskite nanocrystal thin film saturable absorber is inserted into the fiber laser cavity. Due to the characteristics of large optical absorption coefficient, high carrier mobility, low defect density, high gain value, and low saturation intensity of CsPbBr3 perovskite nanocrystals, it is more conducive to the output of Q-switched pulsed laser; the central wavelength of the Q-switched pulsed laser is about 1560 nm in the C-band, the maximum pulse repetition frequency is 49.70 kHz, the maximum output power is 1.9 mW, and the shortest pulse width is 7.92 μs.

The invention relates to a D-band high-integration multi-channel transceiver assembly, the upper surface of a feed unit is provided with a plurality of bonding pad arrays used for flip-chip bonding connection with a radio frequency chip, and each bonding pad array corresponds to a transmitting / receiving channel and is connected to a coplanar waveguide port starting from the layer; the CPWG-SIW transition structure starts from a coplanar waveguide port, and signals are transmitted to a port of the SIW first vertical transition structure in the same layer; the SIW first vertical transition structure starts from a port of the SIW first vertical transition structure, a signal is transmitted downwards to the SIW second transmission line through the SIW first vertical transition structure, after phase adjustment of the SIW second transmission line, the signal is transmitted upwards to the SIW third transmission line, the SIW third transmission line ends in an SIW resonant cavity of the antenna unit, signal energy excites a resonant field in the SIW resonant cavity, and the signal energy is transmitted to the SIW second transmission line through the SIW first vertical transition structure. And the radiation is effectively radiated into the free space through the radiation gap. The targets of feed network broadband matching, low signal transmission loss, low antenna radiation sidelobe and high gain are achieved.

The invention discloses an avalanche photodetector structure with an adjustable receiving rate and an avalanche photodetector thereof, the avalanche photodetector structure comprises an APD, the APD is composed of a positive electrode layer, an absorption layer, a gain layer, a substrate layer and a negative electrode layer, the gain layer comprises a charge control region and an avalanche multiplication region, and the negative electrode layer only comprises a negative electrode; the amplifier further comprises a plurality of multiplication control regions, at least one added avalanche multiplication region and a negative electrode added corresponding to the avalanche multiplication region, the multiplication control regions and the added avalanche multiplication region are located in the gain layer, the avalanche multiplication regions are arranged independently, the negative electrodes are arranged independently, and the multiplication control regions, the avalanche multiplication regions and the negative electrodes are arranged in a one-to-one correspondence mode; the multiplication control region and the charge control region act independently or jointly to realize regulation and control of two or more avalanche multiplication regions. The APD has the advantages that the APD gain can be adjusted in a large range, two-gear adjustment of low bandwidth and high gain and high bandwidth and low gain is achieved, and the APD can be used for receiving optical signals with different rates.

The application relates to a polarization reconfigurable antenna based on a substrate integrated waveguide and an artificial surface plasmon, and belongs to the technical field of antennas. The application aims to solve the problems of fixed polarization characteristics of a traditional antenna, low gain of an existing polarization reconfigurable antenna, and limited beam scanning angle of a leaky-wave antenna. The antenna comprises two groups of 45-degree linear polarization antenna units (SSPP units constructed based on a SIW resonant cavity and a periodic 45-degree rectangular slot) arranged orthogonally and a power divider with a 90-degree phase difference. The power divider is selectively driven to work by controlling the switching state of PIN diodes. By controlling the state of the diodes, dynamic switching of +45-degree linear polarization, -45-degree linear polarization and right-handed circular polarization can be realized. Meanwhile, the antenna has high gain (up to 14.7dBi) and a beam scanning capability of about 43 degrees within a frequency range of 11.5-14.5GHz, and is suitable for wireless communication, radar systems and unmanned aerial vehicle detection.

The application discloses a resonant converter wide-range power and gain adjustment and efficiency optimization method based on hybrid modulation of out-of-phase and frequency conversion and a DC / DC converter. The method comprises the following steps: constructing a total loss model according to preset converter parameters; obtaining a first total loss curve and a plurality of second total loss curves under a preset input voltage by using the total loss model, obtaining a loss intersection point based on the first total loss curve and the second total loss curve, and setting an out-of-phase angle corresponding to the loss intersection point as an optimal modulation switching angle; collecting a real-time input voltage and a load state to calculate a target out-of-phase angle; when the target out-of-phase angle is smaller than the optimal modulation switching angle, adjusting the size of the target out-of-phase angle based on an out-of-phase modulation mode; and when the target out-of-phase angle reaches the optimal modulation switching angle after adjustment of the out-of-phase modulation mode, adjusting a switching frequency based on a frequency conversion modulation mode. The application can solve the problem of sharp reduction of efficiency of a traditional converter under low-gain light-load demand.

The technology described herein is directed towards remotely controlling the direction and the signal strength of a beam reflected from a reconfigurable intelligent surface. A modular design of interconnected, communicatively coupled fundamental modules of unit cells facilitates a straightforward assembly process in which the aperture of the reconfigurable intelligent surface can be scaled by tiling together the modules. The reconfigurable intelligent surface aperture can be remotely fine-tuned with respect to gain and beam reflection direction upon receiving a control signal (e.g., a nine-bit digital code through infrared). Depending on a given scenario, the reflected beam be controlled to reflect an electromagnetic wave (e.g., mmWave) as a concentrated, high-gain coverage beam in a specified direction, a more expansive, low-gain coverage area beam in the specified direction, or something in between, e.g., medium signal strength and medium coverage area.

The present invention discloses a quantum dot laser with a low threshold and a preparation method thereof, which includes a quartz substrate, a silica periodic grating, a quantum dot layer, and a silica protective layer stacked in sequence. The quantum dot layer is composed of closely packed mercury selenide quantum dots with a diameter of 4.8 nm to 6.6 nm, mercury sulfide quantum dots with a diameter of 4 nm to 5.2 nm, quantum dots with a core / alloy / shell structure of mercury selenide / mercury cadmium selenide / cadmium selenide with an effective exciton diameter of 4.8 nm to 6.4 nm, or quantum dots with a core / alloy / shell structure of mercury sulfide / mercury cadmium sulfide / cadmium sulfide with an effective exciton diameter of 4 nm to 5 nm. The present invention realizes environmentally stable electron doping in quantum dots by controlling the size of the quantum dots, uses the doped quantum dots as the gain medium of the laser, and further realizes a low gain threshold, a low laser threshold, sustainable continuous laser output, and a designable output wavelength.

The invention discloses a high-dynamic-range imaging CMOS camera based on a K7 gigabit network. The high-dynamic-range imaging CMOS camera comprises a camera shell 9, and a high-dynamic-range imaging CMOS camera body is installed in the camera shell 9. The CMOS camera body comprises a CMOS sensor chip 1, an FPGA (Field Programmable Gate Array) programmable logic device 2, a DDR3 (Double Data Rate 3) high-speed memory 3, a FLASH memory chip 4, a gigabit Ethernet interface 5, a GPIO (General Purpose Input / Output) isolation interface 6 and a power supply module 7. The FPGA chip receives high-gain and low-gain 2048 * 2048 resolution image data from the CMOS sensor chip at the same time, data caching is carried out through the DDR3 high-speed memory, high-dynamic-range image synthesis is completed in real time, images with 46 frames per second (the resolution is 2048 * 2048) and the dynamic range reaching 70.3 dB are output through the gigabit Ethernet interface, and working parameters of the camera can be configured through a computer.

The invention provides a radio frequency power amplifier circuit, a radio frequency front-end chip and a radio frequency front-end module, and relates to the technical field of radio frequency power amplifiers. In the first gain mode, the biasing circuit can control all transistors in all power amplifiers to be switched on; and in the second gain mode, the biasing circuit can control all transistors between the cascade output ports and the grounding end in all the multiplexing power amplifiers to be switched on, and the switching circuit can control cascade connection among all the multiplexing power amplifiers and output a target radio frequency signal through the output matching circuit. Therefore, a high-gain first gain mode is realized by controlling all the transistors in all the cascaded power amplifiers to work, and a low-gain second gain mode is realized by controlling part of the transistors in the multiplexing power amplifiers to work, so that multi-gain mode work of the radio frequency power amplifier circuit is realized; the radio frequency power amplifier circuit is prevented from working in a deep rollback state, and high efficiency of the radio frequency power amplifier circuit in different gain modes is ensured.

The application relates to the technical field of ground penetrating radar antennas, and discloses an ultra-wideband high-gain Vivaldi antenna loaded with wave-absorbing materials, which comprises a dielectric substrate with a feeding end and a radiating end arranged oppositely and comprising a first plate surface and a second plate surface arranged oppositely; an antenna radiator arranged on the first plate surface and having two radiation arms, the two radiation arms each having a first radiation arm surface facing each other, the two first radiation arm surfaces extending in a direction away from each other from the feeding end to the radiating end so that a gradually expanding groove is formed between the two first radiation arm surfaces; a circular matching groove is arranged on the antenna radiator and close to the feeding end; a wave-absorbing module is arranged on each side end of the two radiation arms away from each other; a metal director is arranged on the first plate surface and located at the radiating end; a reflector is internally provided with a reflection cavity, at least part of the feeding end is inserted into the reflection cavity, and a spacing is formed between the feeding end and the side wall of the reflection cavity. The Vivaldi antenna can alleviate the defects of low gain at low frequency, insufficient impedance bandwidth and low front-to-back ratio of the conventional Vivaldi antenna.

The application discloses a variable gain amplifier applied to a high-speed optical receiver, comprising a high gain stage, a low gain stage and a common gain load; the high gain stage comprises a high differential input pair tube and a high gain adjusting tube group connected in sequence; the common gain load is connected to the output ends of the high gain stage and the low gain stage simultaneously and is used for synthesizing the output currents of the high gain stage and the low gain stage into an output voltage; the high gain adjusting tube group has a gain adjusting voltage V ctrl1 ; the low gain adjusting tube group has a gain adjusting voltage V ctrl2 ; by independently controlling V ctrl1 and V ctrl2 , the total gain and the linearity of the amplifier can be adjusted coordinately. The application adopts the high gain stage and the low gain stage to control the circuit gain, the high gain stage provides higher gain for the circuit, and the low gain stage provides better linearity for the circuit, so that the circuit can realize high gain, and the linearity and the gain change range of the circuit are improved.