233 results about "Common-mode rejection ratio" patented technology

The film acoustically-coupled transformer (FACT) has a first and second decoupled stacked bulk acoustic resonators (DSBARs). Each DSBAR has a lower film bulk acoustic resonator (FBAR), an upper FBAR atop the lower FBAR, and an acoustic decoupler between them FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. A first electrical circuit interconnects the lowers FBAR of the first DSBAR and the second DSBAR. A second electrical circuit interconnects the upper FBARs of the first DSBAR and the second DSBAR. In at least one of the DSBARs, the acoustic decoupler and one electrode of the each of the lower FBAR and the upper FBAR adjacent the acoustic decoupler constitute a parasitic capacitor. The FACT additionally has an inductor electrically connected in parallel with the parasitic capacitor. The inductor increases the common-mode rejection ratio of the FACT.

The invention relates to a multi-channel data collection unit, belonging to the technical field of data collection in testing and measurement. The collection unit consists of a plurality of collection channels, a testing channel and a collection unit control module, wherein each collection channel comprises a conditioning circuit which consists of a conventional filter circuit and a voltage protective circuit, an electric switch and a delta sigma analog to digital converter; the testing channel is formed by a delta sigma digital to analog converter; the collection unit control module is realized on the basis of a programmable logic controller; the plurality of collection channels are connected with the collection unit control module; the input end of the delta sigma digital to analog converter is connected with the output end of the collection unit control module; and the output end of the delta sigma digital to analog converter is connected with each electric switch and each delta sigma analog to digital converter of the collection channel respectively. By the multi-channel data collection unit, high dynamic range, low input nose, low harmonic distortion, low crosstalk and high common mode rejection ratio can be realized, and the requirement of low power consumption and low cost can be fulfilled.

The invention relates to a high-performance EEG signal detection circuit provided with a brain-machine interface. The detection circuit comprises a pre-amplifier circuit and a post-amplifier circuit, wherein the pre-amplifier circuit consists of a first-level amplifier circuit and a second-level amplifier circuit which are connected by a high-pass filter circuit; and the pre-amplifier circuit is connected with the post-amplifier circuit by a 50Hz trap circuit and a low-pass filter circuit. The detection circuit has the characteristics of high input impedance, high common mode rejection ratio, high gain, low noise and low drift, and has the advantages of simple structure, strong capacity of resisting disturbance and good reliability. The invention can be used as a high-performance EEG signal detection circuit, and lay a foundation for realizing the brain-machine interface.

Programmable differential capacitance is implemented in equalization circuits. The programmable differential capacitance improves the common mode rejection ratio of circuits processing differential signals of various frequencies and voltage swings. Multiple capacitance devices provide the programmable capacitance, which provides an equalization circuit with different, selectable (i.e., programmable) values of capacitance for boosting the transition speed and strength of differential signals processed by the equalization circuit.

There are provided a method and a system for characterizing the CMRR of an ICR under test, which employ highly coherent light from two continuous-wave (CW) single-frequency lasers whose respective optical frequencies mutually differ by an offset defining an “Intermediate Frequency” (f_IF) in the rf electrical baseband. The method involves the coherent mixing of light from these two lasers in the ICR under test. A “tone” in the rf electrical baseband at frequency f_IF is generated by the beating of light from the two single-frequency lasers as they interfere on the photodetectors of the ICR. The resulting tone at frequency f_IF in the output electrical signals of the ICR is then detected and analyzed to characterize the CMRR of the ICR.

The invention discloses a surface myoelectricity acquisition device and a myoelectricity signal processing method thereof. The surface myoelectricity acquisition device comprises a first electrode, a second electrode, a third electrode, a front end amplification module, a leg driving module, a band-pass filtering module, a working frequency filtering module, an electrical level lifting module, an AD (Analogue-Digital) acquisition module, a microprocessor and a digital separation module, wherein the first electrode and the second electrode are connected with the band-pass filtering module by the front end amplification module; the third electrode is connected with the front end amplification module by the leg driving module; the band-pass filtering module, the working frequency filtering module, the electrical level lifting module, the AD acquisition module, the digital separation module and the microprocessor are connected in sequence; the leg driving module is used for extracting a human body reference electric signal so that the effects of rapidly discharging, and effectively damping a human body common-mode voltage signal are realized; the common-mode inhibition rate and the input impedance are improved through the front end amplification module so that the precision of acquired myoelectricity signal data is high.

The dynamic characteristic analysis method of real-time tendency of heart state includes: obtaining electorcardiac waveform with multipath electorcardiac amplifier and 12-bit A/D converter; forming time sequence related heart rate variation scatter diagram by means of space-time correlation technology and scatter diagram technology; extracting time sequence related characteristic parameters, short time-real time characteristic conversion illustration parameter and quantized space-time parameter indexes of characteristic illustration via automatic and manual interaction; classifying the illustration and quantized space-time parameters in artificial neural network; and describing dynamic characteristics and relevant invariance characteristics of heart rate variation in a nine-dimensional and a five-dimensional space with two independent curve surfaces and their boundary to represent the heart function.

The invention discloses a monitoring device and a monitoring method in a distributed-battery management system. The monitoring device comprises a loop structure and an isolation structure, wherein the loop structure comprises a low-voltage loop and a high-voltage loop; the high-voltage loop comprises an operational amplifier circuit which is integrated by use of single chips with high common mode rejection ratio and adopts a differential inputting-amplifying processing structure; and the isolation structure comprises a communication isolation chip adopting a transformer isolation structure. The monitoring method comprises the steps of receiving a signal, judging whether the signal is received or not, performing initialization settings, acquiring high-voltage loop data, performing transformer-type isolated transmission, processing low-voltage loop data, sending data and judging whether an exit condition is met. Through a technical proposal in the invention, the monitoring device and the monitoring method realize high security, reliability and extremely high accuracy in a battery monitoring process, as well as continuous rapid sampling, and have no special requirements on power supply sources.

This invention relates to a fully differential non-inverting parallel amplifier for detecting biology electrical signal, including input buffer circuits, differential filter circuits, data selector, non-inverting parallel amplifying circuits and analog-digital circuits. The biology electrical signal, first impeded and converted by the input buffer circuits, and then low-pass filtered by the differential filter circuits, shall be amplified with its common mode signal rejected by passing through the data selector and non-inverting parallel amplifier circuits. At last, the amplified biology electrical signal is output by analog to digital conversion in the analog-digital circuits after its noises beyond signal high frequency band are filtered by anti-aliasing filter net. This invention, with low noise and high common mode rejection ratio, stable baseline, large signal input dynamic range, is reliable and not easy to be saturated. Furthermore, it can support mature PACE Detecting with a low cost. It is notable in social and economical benefits for its simple electrical circuits and easy use in any biology electrical testing equipments and controlling system.

The invention provides a microwave photon doppler frequency shift measuring system and a regulating method thereof. Electro-optical modulation is realized by a radio-frequency signal and an echo signal through a polarization multiplexing mach-zehnder modulator, balance detecting is combined, through digital signal processing, frequency discrimination information is obtained to realize doppler frequency shift measuring of a broadband radio-frequency signal, meanwhile, second order intermodulation distortion is suppressed in a photocurrent detected by a balance detector, and thus measuring performance of the doppler frequency shift measuring system is greatly improved. According to the adopted broadband microwave photon doppler frequency shift measuring system, PDM-MZM is driven by the ratio-frequency signal in a push-pull mode, and second order intermodulation distortion is suppressed by PBS and balance detecting. The microwave photon doppler frequency shift measuring system and the regulating method thereof are simple in structure and high in operability; and the modulator with the high symmetry degree, accurate bias control, and BPD with good responsivity balance and the high common-mode rejection ratio can be adopted to improve the suppression effect of second order intermodulation distortion so as to realize high-accurate broadband microwave photon doppler frequency shift measurement.

The invention discloses an alternating current synchronous motor controller based on FPGA and a control method thereof. The feedback digital processing of a coder and a current sensor and the controlof the current operation of a motor are simultaneously carried out by FPGA; simultaneously, dynamic errors caused by the system error of the feedback current value and a common mode rejection ratio are reduced in the digital filtering of the current feedback sensor; in the feedback process, a polar duty ratio after digital filtering replaces the feedback current value for converting linear data, thereby avoiding the nonlinear processing in the converting process of the current value and the data errors due to multiplication computation; in the processes of the data logic computation and the processing of a current ring and a speed ring, the absolute value and the symbol bit of the data are used as a data combination, thereby simplifying the data processing of programming design; and in addition, a uniform synchronous clock is supplied in the control and renovating process of the speed ring and the current ring, thereby eliminating the errors caused by a time sequence problem in the data transmission process in the computation and the control of the current ring and the speed ring.

The invention discloses a balanced headphone based on a USB-C plug and a mobile terminal. The headphone comprises a headphone cable; and a headphone unit and a USB-C plug which are connected with the headphone cable. The headphone cable comprises a left positive transmission line and a left negative transmission line that are used for transmitting left channel analog differential audio signals; and a right positive transmission line and a right negative transmission line that are used for transmitting right channel analog differential audio signals. The USB-C plug comprises a first interface connected with the left positive transmission line, a second interface connected with a left negative transmission line, a third interface connected with the right positive transmission line and a fourth interface connected with the right negative transmission line. The first interface and the second interface are symmetrical first channel interfaces. The third interface and the fourth interface are symmetrical second channel interfaces. The headphone can effectively achieve a balanced transmission function of audio signals by using symmetrical arrangement of USB-C interfaces, signal crosstalk at the left and right channels will not occur, the stereo separation degree is greatly increased, the common-mode rejection ratio is high, the headphone is not vulnerable to interference, and the signal to noise ratio is significantly increased.

The invention relates to a micro-current signal extraction system. A signal is sampled by adopting a high-precision resistor, a current signal is transformed into a voltage signal; the voltage signal is transmitted to an analog signal preconditioning circuit, and sequentially passes through a primary amplification circuit, an analog filter circuit and a secondary amplification circuit to complete analog signal preconditioning; the signal which is subjected to analog signal preconditioning is output to a digital signal preconditioning circuit, and sequentially passes through an A/D (analog to digital) conversion circuit and a range switching and digital filter circuit; and a required micro-current signal is output after the digital signal conditioning is completed. According to the micro-current signal extraction system, the analog signal and digital signal conditionings are combined, a chopper-stabilizer integrated operational amplifier with high gain, high input impedance and high common mode rejection ratio is selected for preposed amplification of the system, 50Hz power line interference is inhibited by a dual-integral AD analog-to-digital conversion chip, and the I/O (input/output) interfaces can be greatly saved by virtue of 4-line serial communication, and high-efficiency and reliable data transmission can be realized. The micro-current signal extraction system can realize accurate measurement on micro-current, and can be used for insulation monitoring of electrical equipment.

The invention provides a low-frequency balanced zero beat photodetector, which can be used for detecting quantum noises of a laser at the frequency of 50Hz-200kHz and measuring the compression noise spectrum of a non-classical light field in this band. The photodetector comprises a first PIN photodiode (1) and a second PIN photodiode (2) which are of high quantum efficiency, an AC coupling capacitor (3), a low-frequency transimpedance amplifying circuit (4), a DC sampling resistor (5) and a DC same direction proportion amplifying circuit (6). The AC output of the photodetector has the advantages of high gain, low noise, high common mode rejection ratio and so forth, and the photodetector also has a DC output and can monitor the change in the light intensity.

The invention relates to a constant-transconductance rail-to-rail operational amplifier. The constant-transconductance rail-to-rail operational amplifier comprises a rail-to-rail input stage, a gain stage and an output stage in sequential connection. The rail-to-rail input stage a PMOS (p-channel metal oxide semiconductor) differential pair, an NMOS (n-channel metal oxide semiconductor) differential pair, PMOS differential pair and NMOS differential pair tail current sources and an NMOS differential pair load circuit, and the PMOS differential pair and the NMOS differential pair are complementary. The gain stage comprises a self-bias cascade current mirror, and source electrodes of NMOS tubes and PMOS tubes of the PMOS differential pair and the NMOS differential pair are connected with the self-bias cascade current mirror. The output stage comprises a first PMOS tube, a first NMOS tube and a Miller compensator, the first PMOS tube and the first NMOS tube are in common-source connection, grid electrodes of the first PMOS tube and the first NMOS tube are connected with the self-bias cascade current mirror, and the Miller compensator is formed by series connection of a Miller compensation capacitor and a compensation resistor. The constant-transconductance rail-to-rail operational amplifier has advantages that input stage constant transconductance in a full voltage operating range can be guaranteed effectively, the whole circuit structure is high in stability, the operating voltage range of the operational amplifier is expanded, low-voltage application is realized, and the common-mode rejection ratio of the operational amplifier is increased.

An apparatus for detecting the bipolar HF wave of ventricle on the surface of body is composed of a movable unit consisting of signal acquisition circuit, amplifier, A/D converter and emitting module, and a fixed unit consisting of data receiver, USB communication unit, PC algorithm processing unit and output module. Its detecting method including signal conversion and removal of interference and noise is also disclosed.

The invention discloses an operational amplifier with low supply voltage and high common-mode rejection ratio. The operational amplifier comprises a main transconductance level circuit, a secondary transconductance level circuit, a first-level load circuit and a second-level amplification circuit, wherein the main transconductance level circuit comprises a fifth P-type metal oxide transistor, a sixth P-type metal oxide transistor, a seventh P-type metal oxide transistor, a fourth N-type metal oxide transistor and a fifth N-type metal oxide transistor; the secondary transconductance level circuit comprises a second P-type metal oxide transistor, a third P-type metal oxide transistor, a fourth P-type metal oxide transistor, a second N-type metal oxide transistor and a third N-type metal oxide transistor; and the second-level amplification circuit comprises a first P-type metal oxide transistor, a first N-type metal oxide transistor, a first capacitor and a first resistor. The operational amplifier disclosed by the invention can ensure the characteristics of high common-mode rejection ratio and high power supply rejection ratio under low supply voltage.

The invention discloses a front-end processing circuit for physiological electric signal collection. The circuit comprises a left collection unit, a right collection unit, a simulation power source AVDD and an integrated ADC. Electric signals collected by the left collection unit and the right collection unit are connected through two capacitors C1 and C2 with the identical capacitance, a bias voltage Vz is obtained after voltage partitioning is performed on the simulation power source AVDD by two resistors R3 and R4, the Vz is connected to the rear portions of the capacitors C1 and C2 through two identical impedance devices Z1 and Z2 separately, and the electrical signals processed by the circuit are output after being amplified by the integrated ADC. According to the scheme, the circuit compatibility can be greatly improved, the collection front-end common mode rejection ratio can be increased, and the human power frequency noise can be effectively restrained. Meanwhile, the frequency response of the collection front-end can be flexibly controlled, and the circuit can be widely applied to the field of collection of various weak signals.

The invention discloses a weak current detecting circuit of a nitrogen-oxygen sensor, which comprises a current-voltage conversion circuit, a differential low-pass filter and an instrument operationalamplifier, which are connected in sequence. The current-voltage conversion circuit is formed by connecting a sampling resistor to a signal loop; the current-voltage conversion circuit is used for converting a current signal collected by a nitrogen-oxygen sensor into a voltage signal of N times; after high-frequency interference is filtered by the differential low-pass filter, the voltage signal is output after being accurately and effectively amplified by an instrument operational amplifier, wherein the value of N is equal to the value of resistance of the sampling resistor. The weak currentdetecting circuit of a nitrogen-oxygen sensor in the invention can accurately amplify the weak voltage signal. Such an instrument amplification circuit has the characteristics of low offset, low output error, high signal-to-noise ratio, high common-mode rejection ratio, high gain and the like.

A detection circuit for a non-common mode voltage strain bridge signal is applied to engineering technical fields in a wind tunnel aerodynamic test such as balance signal detection and measurement onmoment, pulling pressure, acceleration and the like, belonging to the signal detection technical field. The detection circuit is characterized by comprising a symmetric precision excitation power supply, an instrumentation amplifier, a strain bridge and the like, wherein, the symmetric precision excitation power supply is used for supplying excitation voltage with symmetric positive and negative poles for the strain bridge so as to eliminate common mode voltage applied to the poweramp instrumentation amplifier; the relative effective signal can be generally reduced by 40dB to 80dB; and the instrumentation amplifier with high input impedance performs differential amplification on the measurement signal output by the bridge to generate an electrical signal which facilitates to be measured. The detection circuit has the advantage that: the bridge outputs non-common mode voltage, which can improve signal measurement accuracy by fully utilizing high common mode rejection ratio property of the instrumentation amplifier.

A method and apparatus for providing high common-mode rejection ratio (CMRR) in a single-ended CMOS operational transconductance amplifier is disclosed. A common-mode feedback boosts the OTA CMRR, while allowing integration of conventional OTA improvements.