111results about How to "High rejection ratio" patented technology

The invention provides a continuous wave radar feed-through nulling system and a continuous wave radar feed-through nulling method. The system comprises an antenna device, a transmitting channel, a receiving channel and a signal processor, wherein the antenna device consists of a transmitting antenna and a receiving antenna; the transmitting channel consists of a filter and amplifier module, an up-conversion module and a power amplifier; the receiving channel consists of a low-noise amplifier, a down-conversion module, a filter and amplifier module and a quadrature dDemodulation module; and the signal processor comprises an analog signal conditioning unit circuit and a digital signal processing unit circuit. In the invention, through the sampling of an orthogonally demodulated signal and the real-time self-adaptive nulling of the signal, feed-through signals are prohibited and the measurement accuracy of the system is improved. Meanwhile, the video nulling system provided by the invention also has the characteristics that: the scheme is simple; the implementation is easy; and the like.

The invention belongs to the technical field of integrated circuits and specifically relates to a high mains rejection ratio low dropout voltage linear voltage regulator with a feedforward transconductance, which consists of an error amplifier, a buffer, a PMOS pass transistor, a feedforward transconductance, two feedback resistors and a filter capacitor, wherein the error amplifier is a current mirror amplifier consisting of a tail current source, a PMOS input differential pair and three groups of current mirrors. The mains voltage fluctuation influences the output mainly via two paths of the PMOS pass transistor and the parasitic resistor of and PMOS pass transistor. The feedforward transconductance transforms the perturbation of the mains voltage into the perturbation of the current, and then the perturbation of the current is transformed into the in-phase voltage perturbation of the grid of the pass transistor via the parasitic resistor of the error amplifier. The influence of the mains voltage perturbation on the output can be eliminated by the control of the gain of the feedforward transconductance so as to realize high mains rejection ratio. The invention can optimize the mains rejection ratio within a wider range of load current and does not reduce the efficiency of the low dropout voltage linear voltage regulator.

The invention discloses a low noise bandgap reference circuit and a reference source generation system. The reference source generation system comprises a bandgap reference generation circuit, a low dropout linear voltage stabilizing circuit and the low noise bandgap reference circuit. The low noise bandgap reference circuit comprises a starting circuit, a clamping circuit, a temperature coefficient compensation circuit and an output circuit, wherein the starting circuit is used for supplying starting voltage to other circuits and is turned off after other circuits are started; the clamping circuit comprises four metal oxide semiconductor (MOS) tubes which are connected by a current mirror structure to realize a clamping function; the temperature coefficient compensation circuit is used for performing temperature coefficient compensation on voltage which is output by the clamping circuit and generating reference voltage which is irrelevant to temperature; and the output circuit is used for outputting second reference voltage. The reference source generation system generates extremely low noise and has high power rejection ratios.

The invention discloses an ultraviolet light detector with a titanium dioxide nanotube array serving as a matrix and a preparation method thereof. The ultraviolet light detector comprises a titanium sheet substrate (1), the titanium dioxide nanotube array (2), an insulating layer (3) and a graphene film (4) sequentially from bottom to top, extraction electrodes (5) are arranged on the lower surface of the titanium sheet substrate (1) and the upper surface of the graphene film (4) respectively and are connected with a current measurer (6). The titanium dioxide nanotube array is prepared on the titanium sheet substrate by an anodizing method, oxygen vacancy of the array prepared by the method is less, and mismatch of stoichiometric ratio is avoided. Therefore, titanium dioxide is good in crystalline structure after annealing to lead to high response, low dark current and high ultraviolet-to-visible rejection ratio.

The invention discloses a CMOS subthreshold high-order temperature compensation bandgap reference circuit comprising a current mould bandgap reference circuit and a feedback control loop, wherein the current mould bandgap reference circuit comprises six PMOS pipes, four NMOS pipes and five resistors, and the feedback control loop comprises two PMOS pipes and four NMOS pipes. The invention has lower temperature coefficient and higher power supply suppression ratio. By adopting a CMOS technology library with a CSMC0.5mum standard, the obtained temperature coefficient temperature coefficient is after simulation only 0.42ppm / DEG C, and the PSRR under low frequency reaches more than 78dB.

The invention discloses a solar blind ultraviolet photoelectric detector based on an amorphous gallium oxide film and a preparation method thereof, and belongs to the technical field of photoelectricdetectors. The method comprises the steps that the crystal face (0001) Al2O3 is adopted as a substrate, and the substrate is cleaned; then, the cleaned substrate is fed into a settling chamber, a radio frequency magnetic control sputtering technology is applied to the substrate to grow a gallium oxide film; finally, a hollow interdigital mask plate is used for shielding on the amorphous gallium oxide film, a direct current magnetic control sputtering method is adopted for sputtering an interdigital metal electrode on the interdigital mask plate to obtain the solar blind ultraviolet photoelectric detector, the structure is an MSM type sandwiched structure, and the Al2O3 substrate, the amorphous gallium oxide film material and the Ti / Au interdigital metal electrode are arranged from bottom to top. The manufacturing technology is simple, the repeatability is good, dark current is small, the stability is high, the response speed is high, the ultraviolet visible restrain ratio is high, andthe detector conforms to the energy-saving and emission-reducing theory, is suitable for large-scale production, and has the wide development prospect.

The invention discloses a method and a device for strengthening atom steam optical filtering signals by combined Raman. The method combines two characteristics of atom excited Raman gain and Faraday anomalous dispersion effect of atom steam in a single atom steam bubble. The device for realizing the method comprises a narrow band polarization beam splitter, two holophotes, an atom steam bubble with an external magnetic field with a part of size, an aperture slot with adjustable pore size and a pair of Gran Thomson prisms. In the invention, the atom steam optical filtering signals are strengthened by above 10 times in the atom steam bubble with the external magnetic field with a part of size through vertical direction of weak signal light and pump laser polarization and matching frequency, and scattered light and passband external background light of pumping lasers are inhibited by an optical polarization device, therefore, the device has the advantages of high suppression ratio (-105), adjustable optical filtering wavelength and the like. The invention remarkably enhances the atom steam optical filtering characteristic and the detection sensitivity and has important significance to application in the fields of remote laser communication, free space quantum communication and the like.

The invention discloses a sub-threshold full CMOS reference voltage source. A start-up circuit helps a reference voltage source from getting rid of a degeneration bias point to enter the normal working state. A sub-threshold operation amplifier is ensured to run at low power consumption while being larger in gain at the same time. In this way, the voltage rejection ratio of the power supply is increased. An Nano-ampere reference current generating circuit generates a Nano-ampere-level reference current and suppresses the generation of the noise of the power supply so as to provide a current bias for a reference voltage generating circuit. The reference voltage generating circuit is composed of two MOS tube gate voltage differences of different standard voltages, wherein a reference voltage independent of the temperature is obtained through the coadjustment process. According to the invention, no passive resistor, diode or triode is adopted, and the sub-threshold full CMOS reference voltage source is compatible with the standard CMOS process. Therefore, the layout area is greatly reduced, and the production cost is lowered. The sub-threshold full CMOS reference voltage source is small in power consumption, high in power supply rejection ratio, low in temperature drift coefficient and low in power supply voltage regulation rate.

Electrical tomography apparatus comprises: a first electrode; a second electrode; and current driving means for driving an electrical current between the first electrode and the second electrode through a medium, wherein the current driving means comprises: a first transformer having a first winding and a second winding, the second winding having a first terminal and a second terminal; and means for generating an alternating current through the first winding so as to generate an alternating voltage between said first terminal and said second terminal. The apparatus further comprises connecting means arranged to connect the first terminal to the first electrode and the second terminal to the second electrode. Generation of the alternating current in the first winding results in generation of an alternating voltage between the first and second electrodes. In certain embodiments, a current sensing transformer provides an indication of current driven through the medium.

Oscillators are widely used for integration circuits needing internal clocks, such as various switching circuits and digital circuits. In the design of a low-power-consumption integration circuit, power consumption of an oscillator is an important index for balancing quality of the oscillator, the temperature coefficient of an output clock of the oscillator determines deviation of frequency of the oscillator along with changes of temperature, and a lower temperature coefficient benefits improvement of stability of a system; in the design of a common oscillator with a low temperature coefficient, a temperature detection circuit is adopted, the circuit is adjusted according to the detected temperature, and accordingly the aim of reducing the temperature coefficient of the oscillator is achieved, but the temperature detection circuit needs to be additionally arranged in the structure, and accordingly power consumption and the area of the oscillator are increased. To solve the preceding problems, the invention discloses a ring oscillator with a low temperature coefficient under a lower power consumption condition. Circuits of the ring oscillator include a ring oscillation circuit and a bias circuit.

The invention relates to an all-fiber filter based on thin-core fibers. The conventional fiber grating filter has poor temperature stability, and is not suitable for the operation under extreme working conditions. The all-fiber filter comprises a packing box, a single-mode fiber component is arranged by passing through the packing box, and two ends of the single-mode fiber component are connected with a ring flange respectively. The single-mode fiber component comprises three sections of single-mode fibers which are connected in series, wherein the single-mode fibers at two ends adopt standard single-mode fibers, the middle section of the single-mode fibers adopts thin-core single-mode fibers, the three sections of the single-mode fibers are coaxially arranged, and two ends of the thin-core single-mode fibers are fused with one end of the two sections of the standard single-mode fibers respectively. The filter is simple to manufacture, and has good temperature stability and response characteristic to the external refractive index change.

The invention relates to the technical field of simulative integrated operational amplifiers, in particular to a Push-Pull transconductance amplifier with low power consumption and high linearity. The transconductance amplifier comprises a biasing circuit, a Rail-to-Rail input stage and a Push-Pull output stage which are connected in sequence, wherein the biasing circuit is formed by an image current telescope and is used for providing bias voltage for the Rail-to-Rail input stage and the Push-Pull output stage; the Rail-to-Rail input stage adopts a folding NMOS (N-Channel Metal Oxide Semiconductor) differential pair and a PMOS (P-Channel Metal Oxide Semiconductor) differential pair to realize rail-to-rail in a common-mode input range, and adopts negative feedback of a source electrode to realize linear transconductance; the Push-Pull output stage adopts bias with low power consumption to realize push-pull output with low power consumption, and adopts image current amplification to improve the output driving capacity. The transconductance amplifier has the advantages of simple structure, high linearity, low power consumption, high power supply rejection ratio, small chip area and the like, and is particularly suitable for the transconductance amplifier.

The invention discloses a broadband frequency modulation microwave signal generation method based on photonics. The method comprises the following steps: performing optical M-order and optical second-order single sideband modulation on two paths of homologous single-frequency optical carriers by using a microwave local oscillator signal and a baseband / low-frequency electric frequency modulation signal respectively; realizing the cancellation of the optical carrier component by superposing the optical M-order and optical second-order single sideband modulation signals; and converting the superposed optical signal into an electric signal to obtain a broadband microwave signal of which the bandwidth is twice of the frequency modulation range of the baseband / low-frequency electric signal and the central frequency is M times of the frequency of the microwave local oscillator signal. The invention further discloses a broadband microwave signal generation device based on photonics. Frequencymultiplication and up-conversion of baseband / low-frequency electric signals are realized by utilizing a photon technology, and high-frequency-band, large-bandwidth and waveform-reconfigurable frequency-modulated microwave signals can be generated at a relatively low digital-to-analog conversion rate.

The invention discloses an automatic biasing band-gap reference source. A resistor R3 is connected into a current channel of an NMOS transistor M1 in series, one end of the resistor R3 is connected with the drain of an NMOS transistor M3 and connected with the grids of the NMOS transistor M1 and an NMOS transistor M2, grid bias voltages are provided for the NMOS transistor M1 and the NMOS transistor M2, the other end of the resistor R3 is connected with the drain of a PMOS transistor M5 and connected with the grids of the NMOS transistor M3 and an NMOS transistor M4, and grid bias voltages are provided for the NMOS transistor M3 and the NMOS transistor M4; a resistor R4 is connected into a current channel of the NMOS transistor M2 in series, one end of the resistor R4 is connected with the drain of the NMOS transistor M4 and connected with the grids of the PMOS transistor M5 and a PMOS transistor M6, grid bias voltages are provided for the PMOS transistor M5 and the PMOS transistor M6, the other end of the resistor R4 is connected with the drain of the PMOS transistor M6 and connected with the grids of a PMOS transistor M7 and a PMOS transistor M8, and grid bias voltages are provided for the PMOS transistor M7 and the PMOS transistor M8. The automatic biasing band-gap reference source is not sensitive to the power voltages, high in starting speed, low in power dissipation and temperature coefficient and high in power supply rejection ratio.

The invention discloses a band gap reference source eliminating the bulk effect. The band gap reference source eliminating the bulk effect comprises a starting circuit, a nanoampere magnitude-order reference current generating circuit, a temperature compensating circuit and a current mirror. By means of the MOS work characteristics of work in a sub-threshold area, a nanoampere magnitude-order reference current is generated, the cascade current mirror is adopted, power source noise is inhibited, a source electrode coupling differential pair is used for replacing a resistor and a Bipolar transistor adopted in a traditional band gap voltage source, and influences of the bulk effect are eliminated. The method that a MOS gate-to-source voltage with a negative temperature coefficient and a MOS gate-to-source voltage difference with a positive temperature coefficient are mutually adjusted is adopted so that a zero-temperature-drift reference voltage is obtained.

The invention discloses an LDO circuit based on FVF control. The LDO circuit is characterized by comprising a biasing circuit, an FVF control circuit and a load circuit. The created circuit structureadopts the FVF control circuit as a core. Compared with an existing LDO circuit, the LDO circuit has good parameter indexes such as low power consumption, large load current, a high power supply rejection ratio and transient response, and meets the development requirement of the LDO circuit in the future. The circuit structure can be widely applied to an SoC.

The invention discloses a CMOS reference voltage source without Bipolar transistors. The CMOS reference voltage source comprises a starting circuit which is connected between a power source (VDD) and the ground (GND) in parallel, a CTAT voltage generating circuit, a PTAT voltage generating circuit and a current superposed circuit; the output end of the starting circuit is connected with the CTAT voltage generating circuit and used for making the reference voltage source break away from a degeneracy bias point when a power source powers up; the output end of the CTAT voltage generating circuit is connected with the current superposed circuit; the output end of the PTAT voltage generating circuit is connected with the current superposed circuit; the current superposed circuit is used for superposing a current generated in the CTAT voltage generating circuit and a current generated in the PTAT voltage generating circuit, so that a current source having the zero temperature drift is obtained, and the current source generates the reference voltage (Vref) through an active subcircuit. By the adoption of the CMOS reference voltage source with the mentioned composition, BJT and diodes are not used, influence of temperature variation can be eliminated, complete compatibility with a standard CMOS process is achieved, system cost is effectively lowered, and the CMOS reference voltage source has the advantages of being extremely low in power consumption, high in power supply rejection ratio and good in performance.

The invention belongs to the technical field of electronics, and relates to an integrated circuit design technology, in particular to a novel current injection / pulling error amplifier circuit. The error amplifier circuit comprises a first transconductance amplifier, a second transconductance amplifier, a first image current source, a second image current source and a first capacitor C1, wherein the input end of the first transconductance amplifier is a first input end Vref of the error amplifier circuit, the output end of the first transconductance amplifier is connected with the first image current source, the input end of the second transconductance amplifier is a second input end Vin of the error amplifier circuit, the output end of the second transconductance amplifier is connected with the second image current source, and the output end of the first image current source and the output end of the second image current source are connected with one end of the first capacitor C1 to serve as an output end Vea of the error amplifier circuit. The error amplifier circuit has the advantages of being capable of adjusting the output voltage, improving the response speed and response accuracy of a system and improving the stability of the system, and is particularly suitable for an error amplifier.

The invention provides the intermediate-frequency cancellation technology. An intermediate-frequency cancellation system comprises a antenna device, an emitter, a receiver and a controller. The antenna device is formed by an emitting antenna and a receiving antenna. The emitter is formed by a filtering amplifying module, an upper frequency conversion module and a power amplifier. The receiver is formed by a low-noise amplifier, a lower frequency conversation module, a filtering amplifying module and an orthogonal demodulation module. The controller comprises an analog signal conditioning circuit and a digital signal processing unit circuit. By carrying out sampling for orthogonally demodulated signals and real-time self-adaption cancellation for the signals, leaked signals can be restrained and measurement precision of the system is increased. Meanwhile, the video cancellation system is characterized in that the video cancellation system is easy to make and manufacture.

The invention discloses a low-pass filter. A controllable switch and a feedback network are further arranged on the basis of an RC (resistor-capacitor) filter, the input end of a first field-effect tube in the controllable switch is connected with a first end of a first resistor, and the output end of the first field-effect tube in the controllable switch is connected with a second end of the first resistor; when the voltage at a first end of a first capacitor does not reach a first voltage threshold, the first field-effect tube is connected to short circuit the first resistor and to fast charge the first capacitor; when the voltage of the first end of the first capacitor reaches the first voltage threshold, a second field-effect tube is connected to begin to fast charge a second capacitor; when the voltage at a first end of the second capacitor reaches a second voltage threshold, the first field-effect tube is disconnected to restore to an RC filter state. Based on the low-pass filter, not only is the quick start of an LDO (Low Dropout Regulator) circuit guaranteed, but also the effect that an LDO has low noises and a high power supply rejection ratio is guaranteed. The invention further provides a low dropout regulator.

Provided is a voltage regulator including a ripple rejection ratio improving circuit that requires no readjustment such as trimming for each output voltage. An output of the ripple rejection ratio improving circuit is connected to a back gate of a MOS transistor forming a current mirror section or a back gate of an input stage MOS transistor of an error amplifier circuit. With this construction, a ripple at a power supply terminal or a ground terminal and a ripple at an output terminal can be canceled with each other, thereby being capable of improving the ripple rejection ratio.

Disclosed are polyvinylidene fluoride hollow fiber separation membranes and a preparation method thereof, and more particularly, to polyvinylidene fluoride hollow fiber separation membranes, which may be usefully used not only for water treatment, but also in the sewage treatment field, such as domestic waste water, industrial wastewater, or the like because the polyvinylidene fluoride hollow fiber separation membranes possess excellent pure water permeability and chemical resistance such as alkali resistance, etc., when applied as a separation membrane due to excellent alkali resistance while significantly improving hydrophobicity due to an amphoteric substance, which is a disadvantage of the PVDF hollow fiber separation membranes, by preparing a (PVDF) hollow fiber separation membrane with a thermosetting resin in which the amphoteric substance, in which hydrophilic groups and hydrophobic groups are constituted in the form of a covalent bond, has been introduced into a polyvinylidene fluoride (PVDF)-based resin, and a preparation method thereof.

The invention discloses a LDO (Low Dropout Regulator) with a wide input voltage range and a high power supply rejection ratio and belongs to the technical field of power electronics. The LDO comprisesan error amplifier, a power module, a pre-step-down module, a high voltage resistant module and a power supply rejection ratio enhancement module, wherein the pre-step-down circuit module is utilizedfor preprocessing an input voltage of the LDO to obtain a low power supply voltage used for supplying power to a low-voltage circuit part; power is supplied to the error amplifier and the high voltage resistant module so as to obtain a high power supply rejection ratio by utilizing the low power supply voltage, and the input voltage range of the LDO is widened by virtue of the high voltage resistant module; meanwhile, by utilizing the power supply rejection ratio enhancement module inside the LDO circuit, the power supply rejection ratio of the LDO at a high frequency end is further improved;finally the input voltage of the LDO is processed by utilizing the power module, a feedback voltage is obtained to control a positive input end of the error amplifier so as to obtain enough loop gainfor improving the output accuracy of the LDO, and the output voltage of the power module is a final output voltage of the LDO. The LDO disclosed by the invention is wide in input range, small in chipoccupied area and high in power supply rejection ratio.

The invention discloses a small active vibration control system based on piezoelectric ceramic and a piezoelectric accelerometer, and relates to the technical field of precision machineries and modern control. The system comprises a micro-vibration source (00), a sensor (10), an acceleration module (20), a displacement module (30), a speed module (40), a first summator (50), an amplifying and filtering module (60), a second summator (70), a driving module (80) and the piezoelectric ceramic. The small active vibration control system has the advantages of simple structure, small size and easiness in integration, and can obtain a wider control band width, wherein the control frequency can achieve 200 Hz or even higher; the electric damping is adopted to replace mechanical damping, so that the realization is simpler; and a displacement signal is adopted as low-frequency drift compensation instead of adopting a method of direct current feedback to execute direct current stability, so that enough low-frequency gain and phase margin are guaranteed, and the control band width and the suppression ratio are effectively improved.

The invention relates to the technical field of color filters, in particular to a color filter based on rectangular lattice arrangement and a preparation method and application thereof. The structureof the optical filter comprises a transparent substrate, a transparent covering layer and nanorods. The nanorods are fixed on the surface of the transparent substrate, the transparent covering layer is filled among the nanorods, and the nanorods are coated in the transparent covering layer. The array formed by the nanorods is arranged in a rectangular lattice, and the distance between the adjacentnanorods is not equal to the shortest distance between the two adjacent rows of nanorods. The transverse and longitudinal periods of the metasurface can be independently changed through the rectangular crystal lattices, so that the transmission spectrum and the filtered color are more meticulously regulated and controlled, and finally, the color filter with higher color saturation is obtained. And secondly, by introducing rectangular crystal lattices, namely setting transverse and longitudinal periods of the metasurface to be different values, the structure can show excellent period insensitivity, so that the stability of the color filter is improved.

The invention discloses an improved low-dropout linear regulator, which comprises: a bandgap reference voltage source circuit, a CMOS two-stage error amplifier circuit, an adjustment tube, a frequency compensation circuit and a feedback circuit. The bandgap reference source circuit provides a voltage independent of the power supply voltage and ambient temperature; the bandgap reference voltage source circuit is connected to a CMOS two-stage error amplifier circuit; the CMOS two-stage error amplifier circuit is connected to a bandgap reference voltage source circuit and a feedback circuit and an adjustment tube; the frequency compensation circuit is connected to the adjustment tube; the adjustment tube is connected to the feedback circuit. The error amplification signal is generated by the CMOS two-stage error amplifier circuit; the adjustment tube is used to help feedback errors and reduce the voltage difference; the phase margin of the circuit is compensated by the frequency compensation circuit, including Miller compensation and ESR (Equivalent Series Resistance) compensation, so that it is relatively easy to meet the requirements of the phase margin; the feedback circuit is used to adjust the output voltage.

The invention relates to a multipoint high-frequency microwave signal generating method; in the method, a 2*2 coupling, a Brillouin scattering device and a light filter are used for extracting pump signals and Stokes signals in one or multiple stages, and then the extracted signals are subject to beat frequency to generate one or a plurality of high-frequency microwave signals. The method comprises the following steps: firstly, designing an annular cavity structure based on Brillouin scattering, and arranging a Brillouin scattering device in the annular cavity so as to simultaneously obtain pump signals and Stokes signals in multiple stages; secondly, selecting two or a plurality of laser wavelengths the frequency interval of which is equal to that of the target microwave signal by using the light filter based on a preset reflectance spectrum, wherein all frequency components except for the selected laser wavelengths are inhibited; and thirdly, carrying out the beat frequency on the selected laser wavelengths to generate one or a plurality of microwave signals of which the frequencies are approximately integral multiples of 11GHz.

The invention discloses a constant-current source circuit. The constant-current source circuit comprises a voltage reference generator and a constant-current source generator, wherein the voltage reference generator is used for generating the voltage reference of 6V ad outputs the voltage reference to the constant-current source generator; the constant-current source generator is used for generating a high-stability and high-accuracy constant-current source by use of the voltage reference. The constant-current source circuit is simple and free from temperature compensation, and has the characteristics of high power supply rejection ratio (up to 10<-8> to 10<-10>), high accuracy (+ / -1ppm), good temperature stability (not greater than + / -5ppm, high safety, adjustable load and the like.

The invention belongs to the technical field of rail transit. The invention discloses a narrowband wireless communication system and a narrowband wireless communication method, the narrowband wirelesscommunication system is used for communication between vehicle-mounted equipment and ground equipment, the narrowband wireless communication system comprises an application layer, a security layer, adata link layer and a physical layer, wherein the application layer receives or outputs communication data for interaction between the vehicle-mounted equipment and the ground equipment; the securitylayer adopts a secure transmission protocol to ensure the information security of communication data and the transmission security of the communication data; the data link layer provides processing and output of communication data; the physical layer transmits a bit stream on a bottom wireless channel, performs source channel encoding and decoding, modulation and demodulation on communication data, and sends and receives signals. On the basis of high reliability, the transmission rate of the system can be improved, and the out-of-band rejection ratio is high.