72results about How to "Reduce noise floor" patented technology

The invention relates to an integrated measurement system to detect a quantity of magnetic particles in a sample. The measurement system includes a substrate. An electromagnetic (EM) structure disposed on the surface of the substrate is configured to receive a sample including the magnetic particles in proximity thereof. The integrated measurement system also includes an electrical current generator disposed on the surface of the substrate which is electro-magnetically coupled to the EM structure. The electrical current generator is configured to cause an electrical current to flow in the EM structure. The integrated measurement system also includes an effective inductance sensor disposed on the surface of the substrate which is configured to measure a selected one of an effective inductance and a change in effective inductance. The invention also relates to a method to determine the number of and / or the locations of the magnetic particles in a sample.

The invention discloses a frequency synthesizer for driving phase-locked loop after up-converting DDS. The frequency synthesizer for driving phase-locked loop after up-converting DDS comprises a DDS circuit (5) and a phase-locked loop circuit (7); the output end of a highly stable crystal oscillator (1) is connected with the input end of a first 3 dB power divider (2); the output end of the first 3 dB power divider (2) is connected respectively with the input ends of a first direct frequency multiplier circuit (3) and a second direct frequency multiplier circuit (4); the output ends of the first direct frequency multiplier circuit (3) and a FPGA control circuit (8) are respectively connected with the input end of the DDS circuit (5); the output ends of the second direct frequency multiplier circuit (4) and the DDS circuit (5) are respectively connected with the input end of a frequency mixing filter circuit (6); and the output end of the frequency mixing filter (6) is connected with the input end of the phase-locked loop circuit (7). The frequency synthesizer for driving phase-locked loop after up-converting DDS solves the problems of the prior art such as high stray, high phase noise, large physical dimension and high power consumption exceeding standard, due to directly driving the phase-locked loop by the DDS or driving the phase-locked loop after up-converting and dividing the DDS.

A spectrally efficient multi-carrier communication apparatus with advanced features of carrier management. The apparatus is flexible to changes in the form of the sub-carrier and their location in frequency. This invention can use non-standard pulses at arbitrary frequencies providing a greater control of the carrier. The additional features can be used for spectral efficiency, to correct signal distortion or for privacy. Also disclosed is a novel multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM), preferred embodiments of the transmitter and receiver. Two complementary algorithms help the invention excel among other existent methods. The disclosed algorithms can similarly be adapted to other systems. A correction method for spectrally efficiency is calibrated to all desired noise levels for maximum benefit. An iterative multi-carrier reduction method dramatically reduces the error on overlapped subcarriers.

The invention relates to the technical field of optical communication, in particular to a multichannel parallel photoelectric detection circuit structure which comprises a detector, a first-stage amplification unit, a second-stage amplification unit, a filtering unit and a multichannel synchronous ADC which are connected in sequence. The detector converts the optical signal into a current signal;the first-stage amplification unit is composed of a transimpedance amplifier and amplifies the current signal into a voltage signal; the second-stage amplification unit is composed of n operational amplifiers with different amplification factors, and is connected behind the trans-impedance amplifier in parallel to form parallel n channels; the filtering unit consists of n low-pass filters with different bandwidths and is connected behind the n operational amplifiers in parallel; and the multi-channel synchronous ADC is connected behind the n low-pass filters, and synchronously acquires data under n magnification times. The circuit adopts a multi-channel parallel structure, can collect multi-gear gain signals at the same time, improves the detection efficiency, effectively reduces the noise, improves the signal-to-noise ratio, and improves the dynamic range of detection.

The invention discloses an audio modulation circuit and electronic equipment. The audio modulation circuit comprises an integral amplification module which comprises an integrator and a common-mode modulator, wherein the integrator is used for carrying out operational amplification on an input differential signal and outputting a first amplification signal and a second amplification signal, signallevel values of the first amplification signal and the second amplification signal are symmetrical about a common-mode reference voltage, and the common-mode modulator is used for outputting dynamically adjusted common-mode reference voltage to the integrator according to the first amplification signal and the second amplification signal; and a first comparator and a second comparator connected to two output ends of the integral amplification module respectively and used for comparing the first amplification signal and the second amplification signal with a modulation signal and outputting acorresponding first pulse width modulation signal and a corresponding second pulse width modulation signal. The power consumption of the audio modulation circuit is reduced.

The invention discloses a noise floor suppression method for a remote coverage system. The noise floor suppression method comprises the following steps of detecting the output power of an active remote unit in the remote coverage system; according to a detection result, adjusting the output power of the active remote unit within a preset range. The invention also discloses a noise floor suppression device for the remote coverage system. The noise floor suppression device comprises an output power detection module and an output power adjustment module. The noise floor suppression method and the noise floor suppression device for the remote coverage system can be used for automatically suppressing noise floor of the remote coverage system. By presetting a control range for the output power of the active remote unit, the output power of the active remote unit is adjusted in real time; therefore the output noise floor of the remote coverage system is controlled in a reasonable range, and the influence on the receiving sensitivity of a base station and a mobile terminal is reduced. The noise floor suppression method and the noise floor suppression device for the remote coverage system are easy to implement, convenient to use, low in cost and convenient to promote and apply.

The invention provides an active noise reduction system for eliminating noise floor interference, which comprises at least one noise reduction channel. The noise reduction channel comprises a microphone, an AD converter, a noise reduction filter and a DA converter, wherein a programmable gain amplifier is connected between the microphone and the AD converter for adjusting an input signal of the microphone; a first dynamic range expansion module is connected between the AD converter and the noise reduction filter for expanding the dynamic range of the AD converter; a second dynamic range expansion module is connected between the noise reduction filter and the DA converter for expanding the dynamic range of the DA converter. The active noise reduction system for eliminating noise floor interference in the invention expands the dynamic range of the AD converter and the DA converter and reduces the noise floor of the noise reduction headset.

The invention provides a phase noise measurement device and measurement method based on laser frequency discrimination and cross correlation processing. A laser phase lock cross correlation processingphase noise measurement device comprises two identical independent measurement links, each of which comprises a laser source module, a delay line module, a photoelectric mixing module and a photoelectric conversion module, and in addition, a to-be-tested signal module and a data collection and cross correlation algorithm processing module are shared by the both links. By adopting the phase noisemeasurement device and measurement method provided by the invention, the bottom noise of the measurement links can be reduced, the noise sensitivity can be improved, and the link measurement accuracycan be improved.

A drift-adjusted interferometer and optical trap are disclosed that employ two reference beams with an optical property that allows them to be separated from the two trapping beams. The reference and trapping beams are combined collinearly and optically inverted so that each reference beam overlays with the opposite trapping beam. Each pair of beams is then focused on a microsphere and the resulting four back-focal plane interferometry signals are monitored such that the relative motion between a given trapping beam with its overlaid reference beam provides a direct measurement of the physical drift occurring due to mechanical drift of the differential path components.

The invention discloses an audio modulation circuit and electronic equipment. The audio modulation circuit comprises a common-mode modulator, wherein the common-mode modulator is used for comparing apair of differential signals of which the level values are symmetrical about a common-mode reference voltage with a first reference voltage and a second reference voltage, and dynamically adjusting the common-mode reference voltage on the basis of a preset common-mode reference voltage VC according to a comparison result. The power consumption of the audio modulation circuit is reduced.

The invention provides an angular velocity detection method of a fiber-optic gyroscope, which comprises the following steps of generating at least one group of detection light, wherein each group of detection light comprises a beam of clockwise light which is transmitted clockwise in the fiber-optic gyroscope and a beam of anticlockwise light which is transmitted anticlockwise in the fiber-optic gyroscope, performing phase modulation on each group of clockwise light and counterclockwise light by adopting a modulation signal with a preset frequency, and determining the preset frequency according to the noise spectrum curve of each group of clockwise light and counterclockwise light transmitted in the fiber-optic gyroscope, and acquiring interference signals of each group of clockwise lightand anticlockwise light, and obtaining an angular velocity detection result according to the interference signals. The frequency of the modulation signal is set in the broadband noise frequency band,the noise floor can be greatly reduced, and the short-time migration performance of the fiber-optic gyroscope is improved. And meanwhile, the influence of the trailing effect is reduced due to the pull-open of the frequency points, so that the phase error caused by 1 / f noise can be reduced to a great extent, the short-time migration performance of the fiber-optic gyroscope is improved, and the index of the ultra-high-precision fiber-optic gyroscope strides into a new step.

An embodiment of the invention provides a gene sequencing method and a gene sequencer, and relates to the technical field of gene sequencing. The gene sequencer comprises an excitation light path used for conducting an excitation light beam generated by an excitation light source to a fluid chip with a flow channel, wherein a sample to be tested flows through the flow channel; an imaging light path which is used for collecting fluorescent light generated by the object to be detected through excitation of the excitation light beam and imaging the fluorescent light on an imaging camera arranged on the imaging light path; and a focusing light path used for transmitting a focusing light beam generated by the focusing light source to the fluid chip; and objective lenses are arranged on the excitation light path, the imaging light path and the focusing light path, the objective lenses are located above the fluid chip and can move to change the distance between the objective lenses and the fluid chip, and the focusing light beam and the excitation light beam are focused on the upper surface or the lower surface of the flow channel by changing the distance between the objective lenses and the fluid chip. The reliability of the gene sequencer can be improved, and the detection speed is increased.

The invention discloses a microwave source phase noise measuring device based on a bidirectional optical phase modulator, which comprises a microwave power divider, a laser, an optical circulator, a first branch, a second branch, an optical coupler, a photoelectric detector and a signal analysis device. A bidirectional optical phase modulator, a first fiber bragg grating and a single-mode fiber are sequentially arranged in the first branch, a second fiber bragg grating and an adjustable optical delay line are sequentially arranged in the second branch, the optical circulator is provided with three ports, and the three ports are respectively connected with the laser, the bidirectional optical phase modulator and the second fiber bragg grating. According to the invention, the single bidirectional optical phase modulator is utilized to realize a full-optical-domain frequency mixing function, so that the use of an electric frequency mixer is avoided, and the use of active devices such as a microwave amplifier is reduced. The device has the advantages of simple structure, low cost, large working bandwidth and flat response, the noise floor of the phase noise measuring system is reduced, and the measuring precision and sensitivity are improved.

The invention discloses an audio modulation method, which comprises the steps of performing operational amplification on an audio differential signal, and outputting a first amplified signal and a second amplified signal, the first amplified signal and the second amplified signal being a pair of differential signals of which the level values are symmetrical about a common-mode reference voltage; and dynamically adjusting the common-mode reference voltage according to the first amplification signal and the second amplification signal. The audio modulation method can reduce power consumption.

The invention provides a terminal. The terminal comprises a glass cover plate; an infrared sensor including an emitting end and a receiving; a first light-guiding structure and / or a second light-guiding structure, wherein the first light-guiding structure is fixed between the emitting end and the glass cover plate, and the second light-guiding structure is fixed between the receiving end and the glass cover plate; the first light-guiding structure extends to the glass cover plate from a light-exiting surface of the emitting end in an inclined manner, and an inclination direction is far away from of positive projection of the receiving end on the glass cover plate; and the second light guiding structure extends to the glass cover plate from the light-exiting surface of the receiving end inthe inclined manner, and the inclination direction is far away from the positive projection of the emitting end on the glass cover plate. Therefore, the ground noise of the infrared sensor can be reduced.

The invention discloses a Delta-Sigma modulator with an external disturbance signal. The Delta-Sigma modulator comprises a negative feedback Delta-Sigma modulator module and a noise shaping Delta-Sigma modulator module. The negative feedback Delta-Sigma modulator module is used for transforming an input signal into a pseudo-random output signal, wherein the output signal is used as an external pseudo-random disturbance signal of a post-stage module; and the noise shaping Delta-Sigma modulator module in cascade connection with the negative feedback Delta-Sigma modulator module is used for carrying out noise shaping on the input signal of the whole modulator circuit and outputting a shaped digital signal. According to the invention, with the output of the negative feedback Delta-Sigma modulator module as the external disturbance signal of the noise shaping Delta-Sigma modulator module, the output sequence length of the noise shaping Delta-Sigma modulator is extended effectively, so thatthe smooth output frequency spectrum is obtained and the output ground noises and burrs are reduced effectively.

The invention discloses a digital repeater and a downlink signal processing method thereof. The method comprises the following steps of: S1, receiving a downlink signal transmitted by a base station and separating a downlink radio-frequency signal from the downlink signal; S2, detecting the downlink radio-frequency signal and extracting a base station signal of a base station with highest signal intensity; S3, generating a pseudo-pilot signal and a pseudo-synchronous signal, wherein the pseudo-pilot signal and the pseudo-synchronous signal are respectively the same as a corresponding pseudo-pilot signal and a corresponding pseudo-synchronous signal in the extracted base station signal; S4,combining the pseudo-pilot signal and the pseudo-synchronous signal with the downlink radio-frequency signal to form a selectively amplified downlink radio-frequency signal; and S5, processing the selectively amplified downlink radio-frequency signal and transmitting a processed downlink signal to a mobile terminal. The method reduces pilot pollution, eliminates a self-excitation loop, makes engineering installation and debugging become simpler, and also solves the problem of low call completion rate and handoff drop call.

The invention relates to a method, a device and a system for reducing base station receiving bottom noise and a readable storage medium, and the method for reducing base station receiving bottom noisecomprises the steps: obtaining target RU equipment in RU equipment networking, and setting a power threshold value for the target RU equipment; obtaining an attenuation value according to the actualreceiving power, the power threshold value and a calibration value of the target RU device, wherein the calibration value is a baseband power value of ALC start control triggered by the RU device; andperforming power attenuation on the target RU device according to the attenuation value to reduce the bottom noise of the base station. According to the method provided by the invention, the uplink attenuation is increased by selecting the RU equipment which often reaches the calibration value or is often in the ALC start control state in the RU equipment networking, so that the overall bottom noise of the RU equipment networking is ensured to meet the requirements, and the performance of the system can be ensured to the maximum extent while the bottom noise is reduced.

The invention discloses a data processing method and device for reducing radio frequency interference (RFI) signals in astronomical observation data. The method not only greatly improves the reliability and accuracy of RFI signal detection, but also reduces the time consumption for processing a large amount of data. The data processing method mainly comprises the steps of obtaining data to be processed; conducting statistics on numerical values in the data and drawing a histogram thereof; obtaining an empirical cumulative distribution function of the data; defining a fitting function and performing fitting; marking the RFI; selecting an optimal filter function; and weighting each data point and convolving the data to be processed with the filter function. According to the invention, the computational efficiency and speed are high and massive data can be quickly processed in real time. The method performs convolution processing on RFI data based on a two-dimensional Gaussian function, can perform multiple iteration operations on the data by using the two-dimensional Gaussian function to make the final image smoother and reduce background noise, and can effectively eliminate strong and weak RFI signals.

A silicon-based integrated optical frequency transfer system comprises a local end, an optical fiber link and a user end, and has the advantages of low system noise, compact structure, simple packaging and high reliability.

The invention provides a multi-mode wireless intelligent distribution and coverage system, comprising a main machine control unit, sub-machine distribution units and sub-machine coverage units. The main machine control unit communicates with the sub-machine distribution units and the sub-machine coverage units respectively through a wireless transmission manner, realizes the transmission of radio frequency signals, and controls the sub-machine distribution units and the sub-machine coverage unit. The sub-machine distribution units communicate with the main machine control unit through a wireless accessing method and realize the transmission of the radio frequency signals. The sub-machine coverage units communicate with the sub-machine distribution unit through optical fibers, realize the transmission of the radio frequency signals, and cover the coverage area through a sub-machine coverage antenna as well as receive the uplink signals from the terminals in the coverage area. Each sub-machine distribution unit can be accessed to eight sub-machine coverage units in a parallel-connection manner; and each sub-machine coverage unit supports four-level cascade-connection. With the system of the invention, it is possible to complete the introduction of 2G, 3G and 4G signals at the same time. The system cannot only be mounted and managed conveniently, but also does not occupy the installation space.

The invention discloses an RF emission method and circuit. The method comprise that an RF emission power amplification circuit is determined to be in an OFF state; the RF emission power amplification circuit is started to amplify a signal to be emitted; and the amplified signal to be emitted is emitted. Thus, ground noise can be reduced, and the problem that GSM PvT exceeds the standard is solved to certain extent.

The invention discloses a cascaded optical frequency transfer device and method, and the device comprises a local end, a first optical fiber link, a cascading station, a second optical fiber link and a user side, wherein the cascading station obtains the phase noise introduced by the first optical fiber link and the second optical fiber link at the same time; and a cascading station phase compensation unit compensates for the phase noise introduced by the first optical fiber link and the second optical fiber link at the same time, so that the user side obtains an optical frequency signal with a stable phase, and cascaded optical frequency transfer is realized. The phase compensation bandwidth can be effectively improved through the cascaded optical fiber link, the noise of the system is effectively reduced, and in addition, the system has the advantages of being simple in structure and high in reliability.

The invention provides a GSM-R base station with high interference signal restraining capability. The GSM-R base station comprises a BTS and an antenna, and a pair of dual-bandpass filters or a pair of dual-bandpass GSM-R couplers is arranged between the BTS and the antenna. Each dual-bandpass filter or each dual-bandpass GSM-R coupler comprises a high-frequency signal insertion port RFin and a radio frequency signal port RFout, wherein the high-frequency signal insertion port RFin is an N-K radio frequency head which is connected with a 1 / 2 feeder and connected with the GSM-R base station, and the radio frequency signal port RFout is an L29 (7 / 8)-K radio frequency head which is connected with a 7 / 8 feeder and connected with the antenna. According to the GSM-R base station with the high interference signal restraining capability, due to the dual-bandpass filters or the dual-bandpass GSM-R couplers, the reception bandwidth of the GSM-R base station is compressed, the bottom noise level is lowered, out of band large signal interference is restrained, blocking of GSM-R BTS is prevented, and the interference on the GSM-R BTS caused by intermodulation is effectively reduced.

The invention relates to the field of mobile communication, and in particular relates to an earphone mode switching method, a terminal and an earphone. The method comprises the steps that the terminal acquires the working condition of an audio processing unit of a terminal and the working mode of an earphone connected with the terminal, wherein the working condition of the audio processing unit comprises a call working condition and a non-call working condition, and the working mode of the earphone comprises a digital audio mode and an analog audio mode; and when determining that the working condition of the audio processing unit is not corresponding to the working mode of the earphone, the terminal sends a switching command to the earphone, thus the earphone switches the working mode of the earphone according to the switching command, wherein the call working condition of the audio processing unit is corresponding to the analog audio mode of the earphone, and the non-call working condition of the audio processing unit is corresponding to the digital audio mode of the earphone. According to the method provided by the embodiment of the invention, the problem that in the prior art, the digital earphone cannot make a call or poor in call effect caused by that the sound quality of the traditional earphone is seriously damaged is solved.

The invention discloses a high-signal-to-noise-ratio acoustic sensor based on a multimode optical fiber. The high-signal-to-noise-ratio acoustic sensor comprises a light source part, a modulation part, a mode multiplexing / demultiplexing part, a reference light part, a detection part, a data acquisition part and a sensing part. The light source part, the modulation part, the mode multiplexing / demultiplexing part and the sensing part are sequentially connected, the light source part splits reference light through a first optical fiber coupler of the reference light part, the detection part performs beat frequency on a signal output by the mode multiplexing / demultiplexing part and the reference light, and the output signal is connected to the data acquisition part. According to the invention, a sensing optical fiber is changed from a single-mode optical fiber to a multimode optical fiber, multiple modes in the multimode optical fiber are utilized to sense external sound wave / vibration information, then de-multiplexing is carried out at a detection end or a signal end, and signals detected by N modes are combined, superposed and averaged after diversity, so that the ground noise can be reduced, and the signal-to-noise ratio of the system can be improved; and the sensitivity and the strain resolution of the system are improved.

The invention discloses a harmonic suppression system based on digital-analogue mixed design. The harmonic suppression system comprises two parts, namely a digital circuit and an analogue circuit, wherein the digital circuit comprises a signal processor and an isolation circuit; the analogue circuit comprises a receiving latch and a receiving channel. The harmonic suppression system based on the digital-analogue mixed design is used of the problem of interference of a digital circuit in an existing digital-analogue mixed receiver with the receiving channel via a control line.

The invention relates to the field of terminals, in particular to a light-permeable cover plate and a mobile terminal. The problem that received signal waves are large in bottom noise due to signal waves reflected and emitted by a cover plate in the prior art is solved. The cover plate comprises a light-permeable cover plate body, a light-permeable film layer and an ink layer, wherein the light-permeable film layer is arranged on the first side surface of the light-permeable cover plate body, and comprises at least two layers of light-permeable films sequentially overlapped, and the ink layeris arranged on the second side surface of the light-permeable cover plate body. By means of the light-permeable cover plate, when part of emitted signal waves are reflected, according to the half-waveloss principle, the reflected signal waves can counteract part of signal waves in the bottom noise, the bottom noise is reduced to a certain extent, and the performance of the received signal waves is optimized.

The invention provides an anechoic chamber alternating-current and direct-current multi-magnetic circuit device for low-voltage electrical appliance product detection, which is used for providing current for a low-voltage electrical appliance product to be detected during detection and comprises an alternating-current and direct-current multi-magnetic circuit system and control equipment which are connected with each other, the AC-DC multi-magnetic circuit system is arranged in a load chamber outside the anechoic chamber, the input end of the AC-DC multi-magnetic circuit system is connected with an external 380V alternating current, and the output end of the AC-DC multi-magnetic circuit system is connected with a storage turntable in the anechoic chamber and is used for providing multi-range level AC-DC current required by testing for the low-voltage electrical appliance product to be detected; and the control equipment is arranged in the control cabinet, is positioned outside the anechoic chamber and the load chamber, comprises a signal control system for realizing communication control with the AC / DC multi-magnetic-circuit system and a leakage power supply connected with the storage turntable, and is used for providing leakage current required by the test for the low-voltage electric appliance product to be detected. By implementing the invention, the problems of high-frequency noise and electromagnetic interference caused by the existing current source can be avoided, so that the darkroom bottom noise is reduced, and the test requirements are met.

The invention discloses a class-D audio amplifier, a pulse width adjustment method thereof and electronic equipment. A pulse width modulation module is used for carrying out pulse width modulation on an input signal and outputting a first pulse width modulation signal and a second pulse width modulation signal. A pulse width adjusting module is used for controlling the relative delay between the second pulse width modulation signal and the first pulse width modulation signal according to a first output signal and a second output signal which are output to a load to form a corresponding first delay signal and a corresponding second delay signal. A driving module is used for generating a first output signal and a second output signal which are output to a load according to the first delay signal and the second delay signal, and the pulse width of the first output signal and the pulse width of the second output signal change along with the relative delay. The class-D audio amplifier can adaptively adjust the pulse width of the output signal, and can reduce the power consumption under specific application without introducing the static background noise problem.