41results about How to "Reduce 1/f noise" patented technology

The invention relates to a mixer based on the current multiplexing technology. The mixer comprises a trans-conductance stage circuit, a switching stage circuit and a load stage circuit that are connected successively. The trans-conductance stage circuit employs a current multiplexing structure and a source degeneration inductance structure. The trans-conductance stage circuit is used for realizingaccess of a radio-frequency voltage signal, converting the radio-frequency voltage signal into a radio-frequency current signal, and reusing the radio-frequency current signal repeatedly. The switching stage circuit is used for realizing access of a local oscillator signal and a radio-frequency current signal, controlling conduction of a plurality of arranged switching tubes alternately based onthe local oscillator signal, carrying out switching modulation on the radio-frequency current signal by alternate conduction of the plurality of arranged switching tubes, and generating an intermediate-frequency current signal and transmitting the signal to the load stage circuit. The load stage circuit is used for converting the intermediate-frequency current signal into a voltage signal and outputting the converted signal. Compared with the prior art, the mixer has advantages of simple structure, high conversion gain, high linearity, low noise, low power consumption, and good port isolationperformance.

A device includes a first mixer for production of a first analogue intermediate signal by down-mixing of a radio-frequency signal. The device also includes an A / D converter for production of a first digital intermediate signal, a second mixer for production of a second digital intermediate signal from the first digital intermediate signal, and a third mixer for production of a digital baseband signal from the second digital intermediate signal. The second mixer has a higher sampling frequency than the third mixer.

The invention discloses a combined oceanic electric field sensor and a matching test method thereof. The oceanic electric field sensor comprises a data acquisition station (1) for acquiring and storing electric field signals, a data transmission device (2) for transmitting electric field signals detected by electrodes (16 and 26) to the data acquisition station (1), electrode cabins (3 and 4) for installing a watertight connecting socket (5) and fixing the electrodes (16 and 26), the watertight connecting socket (5) for connection of the electrodes (16 and 26), and the electrodes (16 and 26) for detecting the electric field signals. The self noise of the combined oceanic electric field sensor is reduced, the measuring sensitivity of the electric field sensor is improved, repeated usage of the electrodes is achieved, and the using cost of the combined oceanic electric field sensor is reduced.

The invention discloses a unit circuit of an infrared focal plane readout circuit, which is characterized in that the unit circuit includes: an integral capacitor selection unit, an integral / reset control unit, an input amplifier, a sample hold unit and a source follower unit. The present invention utilizes the reset of the integration / reset control unit to provide a constant infrared detector bias voltage inside the unit circuit without external bias voltage; most of the transistors use P-type MOS tubes, which effectively reduces the noise of the unit circuit; The single-stage amplifier replaces the differential amplifier, which reduces the power consumption of the unit circuit and saves the unit area; two levels of capacitance are designed for selection, which can meet the needs of different background conditions; the integration time can be adjusted according to different detector currents. selection.

The invention discloses a cantilever beam and photoacoustic cell double-resonance enhanced-type photoacoustic spectrum detection system and a method, and belongs to the technical field of trace gas detection. According to the cantilever beam and photoacoustic cell double-resonance enhanced-type photoacoustic spectrum detection system and the method, sound wave generated by excitation of gas molecules with a light source is subjected to coherence stack in an acoustic resonance tube of a resonant photoacoustic cell, so that photoacoubtic signal amplitude is increased effectively; at the same time, fine adjustment on the photoacoustic cell resonant frequency is realized through precise design and temperature control of a cantilever beam structure, so that accurate matching of the cantilever beam resonant frequency with the photoacoustic cell resonant frequency is realized, and the photoacoubtic signals are enhanced further via one step resonant of the cantilever beam; the double-resonanceenhanced-type photoacoustic spectrum method is combined with a phase-locked amplifier to realize super sensitive gas detection. The double-resonance enhancing effect of the cantilever beam and the photoacoustic cell is capable of realizing obvious amplification of photoacoubtic signals, the system working frequency is controlled at kHz order of magnitude, 1 / f noise is reduced greatly, and a technological scheme with competitiveness is provided for super low concentration gas detection.

The invention discloses a system and method for reducing the noise of a tunnel magneto-resistance sensor, comprising: a non-coil shielding cylinder and a driving circuit; wherein, the material of the non-coil shielding cylinder is a high magnetic permeability soft magnetic material; the TMR to be processed The sensor is placed in the center of the non-coil shielding cylinder; the output end of the TMR sensor is connected to the input end of the drive circuit; the non-coil shielding cylinder is based on the supersaturation characteristics of the high magnetic permeability soft magnetic material. The ability to change at high frequency, so that the DC magnetic field to be measured by the TMR sensor will be converted into a high-frequency AC magnetic field, and the 1 / f noise of the TMR sensor will be reduced; the drive circuit will perform phase-sensitive detection and low-frequency detection on the output signal of the TMR sensor based on the reference signal. Through filtering, the sum frequency signal is filtered out, the difference frequency signal is retained, and the 1 / f noise of the TMR sensor is further filtered out. The non-coil shielding cylinder in the present invention does not need to be wound with multi-turn coils, does not introduce new noise, and has a good noise reduction effect.

The invention relates to a circuit of a deep-sea geomagnetic measuring instrument. The precision of the existing device is too low, thereby being lack of practical significance in the application of analyzing the geomagnetic micro-change of a small ocean bottom region. The circuit comprises a power supply circuit, a setting / resetting circuit, a sensing measuring circuit and a main control circuit, wherein, the sensing measuring circuit comprises a single-axis magnetoresistive sensor chip IC4, a dual-axis magnetoresistive sensor chip IC5, three same operational amplifier circuits 5, a high-precision AC chip IC6 and a voltage reference chip IC7. The main control circuit comprises a main control chip IC8, a gyroscope chip IC9, a level conversion chip IC10 and a reading / writing interface J1 of an SD card. The circuit adopts the magnetoresistive sensing technology to constitute a deep-sea geomagnetic measuring circuit and utilizes the characteristics of high sensitivity and low power consumption of the magnetoresistive sensors, thereby having simple circuit connection, reducing the noise by 1 / f and improving the effective resolution.

The present invention is directed to the isolation and cancellation of the offset voltage component typically experienced at the input of sampled-data analog systems. In an exemplary embodiment, offset isolation and cancellation may be performed during normal operation of the sampling circuitry. In an exemplary embodiment, the present invention combines a front-end switching topology with one or more differential integrator stages and a logic algorithm implemented in the differential integrator stages. In operation, the circuitry preferably performs a number of samples for each stage, applies an inversion factor to the samples in accordance with the algorithm and integrates the samples to effect the cancellation of the offset voltage without substantially affecting the sampled input.

The invention relates to an infrared focal plane readout circuit with an offset elimination function, and the readout circuit includes: a level conversion unit, a two-phase non-overlapping clock generation unit, a bandgap reference current source unit, and a transconductance amplifier Unit, transconductance output offset current elimination unit, integral amplification unit with offset voltage elimination technology, integral capacitor selection unit, buffer isolation unit, sample hold unit, buffer output stage unit. The circuit of the present invention can be used to read out the small signal produced by the diode-type uncooled infrared focal plane array; by selecting different integral capacitance values ​​and changing the size of the bias current of the transconductance unit, the amplification factor and integration time of the signal can be adjusted, etc. , to meet the needs of different backgrounds; the invention also includes amplifier input stage offset voltage elimination technology and transconductance output current offset elimination technology, thereby improving the overall accuracy of the readout circuit.

The present invention provides a 1 / f noise suppression system and method based on frequency conversion and digital filtering. The system includes: an optical domain radio frequency shaping module, which is used to form an optical signal with information to be measured and a radio frequency envelope; The frequency conversion module is used to convert the optical signal into an electrical signal, and the electrical signal is frequency-converted and processed to obtain a sampling signal; the digital filtering module is used to perform digital co-square sum and mean value filtering on the sampling signal to obtain an electrical signal. The intensity information is shaped into a radio frequency envelope by optically mixing the original signal, and the signal itself will be amplified. After the electrical frequency conversion, the optical signal with the radio frequency envelope is converted to an intermediate frequency by electrical mixing. Sampling to reduce 1 / f noise and keep away from the interference of its own 1 / f noise can better realize nano-micro information sensing in practical applications, improve performance and expand applications.

The invention discloses an indium-gallium-phosphorus heterojunction bipolar type transistor and a manufacturing method therefor. The indium-gallium-phosphorus heterojunction bipolar type transistor comprises a substrate, a heavily-doped secondary collector region layer, a heavily-doped indium-gallium-phosphorus etching stop layer, a lightly-doped collector region layer, a base region layer, a lightly-doped indium-gallium-phosphorus emitter region layer and a heavily-doped emission cap layer from the bottom up in sequence. The linearity and the reliability of the indium-gallium-phosphorus heterojunction bipolar type transistor can be effectively improved.

The object of the present invention is to provide a receiver which can reduce low-frequency noise generated when it is integrally formed on a semiconductor substrate using a CMOS process or a MOS process. High-frequency amplifying circuit (11), frequency mixing circuit (12), local oscillator (13), intermediate frequency filter (14, 16), intermediate frequency amplifier (15), limiting circuit (17), The FM detection circuit (18) and the stereo demodulation circuit (19) are formed as one-chip components (10). The single-chip element (10) is formed on a semiconductor substrate using a CMOS process or a MOS process, and a p-channel FET is used to form a mixing circuit (12), an intermediate frequency filter (14, 16), an intermediate frequency amplifier (15) and a local The amplifying element contained in the oscillator (13).

The invention provides a band gap voltage reference circuit, and belongs to the field of analog circuits. The band gap reference circuit comprises a first PMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth PMOS transistor, a fifth PMOS transistor, a sixth PMOS transistor, a first PNP audion, a second PNP audion, a capacitor C, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and an operational amplifier. According to the technical scheme, the influence of local oscillator noise and voltage noise on output voltages can be lowered, the precision of a reference voltage is improved, meanwhile, the area of a chip is considered, and the design complexity of the circuit is reduced.

The invention discloses a high-precision polarized navigator, which comprises the following parts to form the polarized receiving system: first polarized lens cone, second polarized lens cone, third polarized lens cone and polarized lens cone, wherein the output direction of polarized receiving system contains light-beam deflecting device, polarized adjustment system and photoelectric detector array sequently, which connects lock-in amplifying circuit, logarithmic amplifying circuit, data gathering card and computer after the photoelectric detector array; the photoelectric detector array transmits the received two paths of polarized signal into electrical signal, which is disposed by computer to realize the navigation of moving object through logarithmic amplifying circuit and lock-in amplifying circuit. The invention simplifies the structure with good reliability and high precision, which is fit for real-time navigation of traffic tool and moving object.

The invention discloses a low-noise MEMS capacitive sensor interface circuit which mainly solves the problems of gain errors and circuit noise deterioration. The device comprises an MEMS mechanical sensing element, an input common-mode control circuit, a capacitance-voltage conversion module and a clock control signal generation module. The MEMS mechanical sensing element is used for converting an external acceleration signal into a variable quantity of an MEMS mechanical capacitor and generating sensor charge signals A and B; the input common-mode control circuit is used for absorbing common-mode components of sensor charge signals, and other differential-mode components are transmitted to the integrating capacitor for signal amplification, so that conversion of capacitor voltage is realized. And the gain precision is improved by introducing the sampling holding capacitor, so that the original high-gain operational amplifier can be replaced by the low-gain operational amplifier. Due to the introduction of the bandwidth compensation capacitor, the interface circuit can work under a clock with higher frequency, and the noise floor of the interface circuit is reduced. The purposes of not additionally increasing the power consumption of the circuit and reducing the noise of the interface circuit are achieved.

The invention discloses a high-precision temperature sensor with correlated double sampling function, which includes a reference voltage source and an analog-to-digital converter, and the reference voltage VREF, temperature voltage VPTAT1 and temperature voltage VPTAT2 output by the reference voltage source are transmitted to the analog-to-digital converter The analog-to-digital converter quantizes the temperature voltage VPTAT1 and the temperature voltage VPTAT2 based on the reference voltage to generate digital temperature information; wherein the temperature voltage VPTAT1 and the temperature voltage VPTAT2 are output on the same branch of the reference voltage source. The invention provides a high-precision temperature sensor with correlated double sampling function, which reduces the output error of the temperature sensor and improves the precision of the temperature sensor.