710 results about "Noise figure" patented technology

A mixing method and mixer structure provide a circuit topology suitable for use in radio receivers, transmitters, tuners, instrumentation systems, telemetry systems, and other systems and devices performing frequency conversion in either homodyne or heterodyne implementations. The inventive mixer may be used for wireless communication devices including radios, cellular telephones, and telemetry systems whether land, sea, airborne, or space based, and whether fixed or mobile. The mixer provides superior intermodulation and harmonic distortion suppression and features excellent conversion loss, noise figure, port match, and port isolation as a result of its circuit topology. The mixer device circuit combines the advantages of series mixing FETs, a triple balanced design using a balanced passive reflection transformer, a precise local oscillator phase splitter, and square wave gate drive having high slew rate signal characteristics to achieve high levels of performance. It is power conservative and offers the advantage of long battery life in portable devices such as portable radios and cellular telephones as it requires only a modest amount of DC and local oscillator drive power, and is useful for operation over at least a multi-decade bandwidth.

System and method for canceling crosstalk in high-speed communications systems. An embodiment comprises precomputing channel pulse responses for a set of communications channels in a communications backplane, precomputing channel signal responses for the set of communications channels in the backplane with a training sequence, estimating noise coefficients using receiver training and the training sequence, storing noise coefficients for each communications channel in the set of communications channels, and canceling noise in a received transmission of a data sequence using the stored noise coefficients. The regularity of the communications backplane enables the precomputing of various values, which reduces computational requirements. Furthermore, it is often the case that a victim receiver has access to the digital data that is being transmitted by its dominant crosstalking transmitters, thereby simplifying noise cancellation.

Devices and methods enable optimizing a signal of interest based on identifying and analyzing the signal of interest based on radio frequency energy measurements. Signal data is compared with stored data to identify the signal of interest. Signal degradation data is calculated based on noise figure parameters, hardware parameters and environment parameters. The signal of interest is optimized based on the signal degradation data. Terrain data may also be used for optimizing the signal of interest.

Apparatus and methods for identifying a wireless signal-emitting device are disclosed. The apparatus is configured to sense and measure wireless communication signals from signal-emitting devices in a spectrum. The apparatus is operable to automatically detect a signal of interest from the wireless signal-emitting device and create a signal profile of the signal of interest; compare the signal profile with stored device signal profiles for identification of the wireless signal-emitting device; and calculate signal degradation data for the signal of interest based on information associated with the signal of interest in a static database including noise figure parameters of a wireless signal-emitting device outputting the signal of interest. The signal profile of the signal of interest, profile comparison result, and signal degradation data are stored in the apparatus.

Systems, methods, and devices enable spectrum management by identifying, classifying, and cataloging signals of interest based on radio frequency measurements. Signal data is compared with stored data to identify the signal of interest. Signal degradation data is calculated based on noise figure parameters, hardware parameters and environment parameters.

A high performance radio frequency receiver includes a low noise amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to a current; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The in-phase and quadrature pulses have a duty cycle of 20-35%. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter. Decreased die size, current drain, cost, and complexity, as well as improvements in gain, 1 / f noise, noise figure, sensitivity, and linearity may result.

An arrangement for bypassing a low-noise amplifier (LNA), intended especially to be used in base stations of mobile networks. For the bypass, a receiver antenna filter (210) has a second output (OUT2) parallel with a first output (OUT1) connected to the LNA. The antenna filter is of the resonator type, and there is a conductive element for each of its outputs in the resonator cavity. Selection between the LNA out-put signal and signal coming direct from the antenna filter is made by a changeover switch (SW). The noise figure of the receiver front stage (220) will improve as the series switch on the signal path, which most degrades the noise figure, is removed between the filter and LNA, and isolation on the LNA bypass path increases.

The invention provides a framing method of the receiver front-end of multimode satellite navigation, which discloses a frontend chip of the receiving RF of multimode satellite navigation which is applicable to a plurality of satellite navigation systems. The method of the invention comprises six modules which are a multimode PF frontend low-noise amplifier / mixer group of monolithic integrated and completed type, a reconfigurable image rejection filter, a band-variable gain amplifier, an analog-to-digital converser, a configurable frequency synthesizer and a multimode control logic module. The reconfigurable module can realize the distribution of functional parameters according to the requirement through the multimode control logic management, causing the working performance to be optimized and meeting the functional requirement on the RF front end of the receiving platform of multimode satellite navigation. The framing method of the invention requires no external supporting accessories and has the advantages of being easy to carrying out cascade connection with preceding and backward stages, high gain, small noise coefficient and good integration. The invention is applied to the current communication and navigation positioning equipment for receiving multimode satellite navigation signals, has a wide application range and quite remarkable economic benefit, is largely on demand, supports the integration making use of multimode satellite navigation positioning information, improves positioning precision and has large social benefit.

A discrete low-noise amplifier designed to operate in a mobile wireless environment uses two cascaded GaAs FETs to achieve 25 dB gain and 0.9 dB noise figure at 2.5 GHz. Active bias control circuitry responsive to monitored amplifier output power automatically and continuously adjusts the drain-source currents, and the load lines, of the cascaded FETs to (i) maintain power consumption at 33 milliwatts in nominal small-signal conditions, and to (ii) provide an elevated input third-order intermodulation intercept point (IP3) and a reduced noise figure during the presence of jamming. A 15 dB improvement in the input IP3 is achieved in large-signal operation. Amplifier operation is supported by an a.c. power detector of enhanced sensitivity and responsiveness because of un-grounded operation.

A modified derivative superposition (MDS) low noise amplifier (LNA) includes a main current path and a cancel current path. Third-order distortion in the cancel path is used to cancel third-order distortion in the main path. In one novel aspect, there is a separate source degeneration inductor for each of the two current paths, thereby facilitating tuning of one current path without affecting the other current path. In a second novel aspect, a deboost current path is provided that does not pass through the LNA load. The deboost current allows negative feedback to be increased without generating headroom problems. In a third novel aspect, the cancel current path and / or deboost current path is programmably disabled to reduce power consumption and improve noise figure in operational modes that do not require high linearity.

A digital ultrasound beam former for ultrasound imaging, that can be configured by a control processor to process the signals from ultrasound transducer arrays with variable number of elements at variable sampling frequencies, where the lowest sampling frequency allows for the highest number of array elements. The maximal number of array elements is reduced in the inverse proportion to the sampling frequency. Parallel coupling of transmit / receive circuits for each element allow adaption of the receive Noise Figure and transmit drive capabilities to variations in the electrical impedance of the array elements.

The invention discloses an electroencephalogram signal feature extraction and classification method of combining a denoising auto encoder (DAE) and a convolutional neural network (CNN). The method includes the steps of: collecting electroencephalogram data through an electroencephalogram signal collection instrument; carrying out preprocessing of abnormal-sample removing, mean removing, signal filtering and the like on the collected data; using the auto encoder, into which a noise coefficient is added, and electroencephalogram signals for training; using hidden layers of the denoising auto encoder as feature data output; then converting obtained feature data into an image-like format; utilizing the convolutional neural network for classification; and finally, utilizing a test data set to carry out a performance test on the trained network. Compared with other traditional methods, the method of the invention can obtain a higher classification accuracy rate and higher robustness.

Apparatus and methods for identifying a wireless signal-emitting device are disclosed. The apparatus is configured to sense and measure wireless communication signals from signal-emitting devices in a spectrum. The apparatus is operable to automatically detect a signal of interest from the wireless signal-emitting device and create a signal profile of the signal of interest; compare the signal profile with stored device signal profiles for identification of the wireless signal-emitting device; and calculate signal degradation data for the signal of interest based on information associated with the signal of interest in a static database including noise figure parameters of a wireless signal-emitting device outputting the signal of interest. The signal profile of the signal of interest, profile comparison result, and signal degradation data are stored in the apparatus.

An AGC circuit includes both wide-band and narrow-band VGAs. Two power monitors monitor the power level of the two VGAs. Based upon the signals provided by the power monitors, the AGC circuit derives two error terms. The AGC circuit filters and combines the error terms to determine a desired adjustment to the total gain and a desired adjustment to the distribution of the gain between the wide-band VGA and the narrow-band VGA. The AGC circuit also minimizes the noise figure of the narrow-band VGA subject to linearity constraints.

Disclosed herein is a PhotoMultiplier Tube (PMT) designed for use with a surface inspection system such as the Surfscan system, which operates at 266 nm wavelength. The inventive PMT is high efficiency, low noise, and low gain, a combination of features that is specific to the application and contrary to the features of PMT's in the art. The inventive PMT is designed to be tuned to a specific narrow band wavelength of incident light, thereby optimizing the QE at that wavelength. It is further designed to combine a small number of dynodes each having substantially higher secondary electron gain than typical dynodes. By designing the PMT in this way, the excess noise factor is dramatically reduced, yielding a much improved S / N, while still maintaining the overall PMT gain in the lower range suitable for use in a surface inspection system.

A tail-tank coupling technique combines two complementary differential LC-VCOs to form a quadrature LC-VCO. The technique reduces phase noise by providing additional energy storage for noise redistribution and by cancelling noise injected by transistors when they operate in the triode region. The resulting noise factor is close to the theoretical minimum 1+γ, similar to a differential LC-VCO driven by an ideal noiseless current source. However, its figure-of-merit is higher, due to the absence of voltage head-room being consumed by a current source. The optimal ratio of tail-tank capacitor to main-tank capacitor for minimizing phase noise is approximately 0.5. The method can be extended to combine any even number of LC tanks resonating at fo and 2fo to form an integrated oscillator producing quadrature phase at frequency fosc and differential output at 2fosc.

Methods and systems for communicating in a wireless network include adjusting power consumption of an analog portion of a receiver in a mobile device based on the needs of the mobile device. In one example, either the gain or noise figure of the low noise amplifier (LNA) in the receiver may be adjusted based on the strength of a received signal. In other examples, the resolution of the receiver analog-to-digital converter (ADC) may be varied based on the signal strength. The dynamic adaptation of analog receiver components for high-end performance when needed and low-end performance when possible further enables a reduction of power consumption in a mobile wireless device.

A parallel optical fiber amplifier having a configuration in which a C-band silica-based erbium-doped fiber amplifier (EDFA) stage and an L-band EDFA stage are coupled together in parallel in such a fashion that a reverse amplified spontaneous emission (ASE) light emitted from the C-band and / or L-band EDFA stage is reused as a secondary pumping source for an amplification in the L-band EDFA stage. In the optical fiber amplifier of the present invention, the reverse ASE light emitted from the C-band EDFA stage and the reverse ASE light emitted from the L-band EDFA stages supplied to the L-band EDFA stage so that they can be reused for improving the power conversion efficiency of the entire system and for reducing the noise factor thereof.

A semiconductor device simulation method includes the step of storing, in a storage unit, a surface potential and threshold voltage obtained by computation, the step of computing thermal drain noise on the basis of the data of the surface potential and thermal drain noise stored in the storage unit, and the step of determining whether or not to reduce thermal drain noise, and reflecting the computation result in simulation of the model when it is determined that thermal drain noise is to be reduced. A drain current Ids of a MOSFET is calculated and substituted into a relational expression for a drain current noise spectrum density obtained from a Nyquist theorem equation, thereby calculating a thermal drain noise coefficient γ of the MOSFET by substituting the current Ids into a relational expression for a thermal drain noise spectrum density which is obtained from the Nyquist logical equation.

The invention discloses an optical frequency domain reflection-distributed vibration frequency sensing and locating device and a demodulation method. A technical method of optical frequency domain reflection beat frequency interference of a self-injective mode locking laser of a linear turning ultra-narrow linewidth whispering gallery mode is adopted in the optical frequency domain reflection-distributed vibration frequency sensing and locating device. The optical frequency domain reflection-distributed vibration frequency sensing and locating device comprises a main interferometer which is used to obtain a sensing signal and an auxiliary interferometer of a clock trigger signal. The demodulation method comprises that wavelength domain information is obtained by the main interferometer, fast Fourier transform is used to transform the wavelength domain information, and then distance domain information is obtained. A group of static reference signals and a group of vibration signals are collected. The distance domain information, namely local distance domain information, is selected in sequence by moving windows. Complex number cross correlation is used on the static signals and the vibration signals of the local distance domain information on each position. According to a noise coefficient of the complex number cross correlation, a position of a vibration point is obtained. A subsidiary summit position of the complex number cross correlation of the local distance domain information on the position of the vibration is picked up, and the subsidiary summit position is vibration frequency information.

Provided is a low noise amplifier with a common source and a source degeneration, which has linearity, power gain, noise factor, and lossless input matching. The low noise amplifier includes: a first inductor having one terminal connected to an input terminal receiving a signal; a second inductor having one terminal connected to a ground; a MOS transistor having a gate connected to the first inductor, a source connected to the other terminal of the second inductor, and a drain transmitting a signal; and a variable capacitor connected between the source and gate of the MOS transistor and varying an input matching frequency at the input terminal.

The invention discloses an active integrated antenna system. The system comprises an antenna pedestal, wherein the antenna pedestal is provided with an antenna array, a feed network, a feed power supply, a monitoring unit and a radio frequency amplification unit. The radio frequency amplification unit is connected with the feed network, the feed power supply and the monitoring unit, so that the radio frequency amplification unit is integrated in the antenna system and a signal can be actively amplified and controlled when the antenna system receives and transmits the radio frequency signal. Because an amplification circuit is integrated in an antenna, the output power is directly connected with the antenna array to be transmitted, no energy loss is caused in the process, and the power loss and increasing of noise coefficient, which are caused by feeder loss, are greatly reduced. In addition, due to the structural design of the system, the system has more advantages in both aspects of cost and reliability.

The invention provides a small-sized double-frequency active navigation antenna device which comprises a suppression plate, a first microstrip patch, a second microstrip patch, a first substrate and a second substrate. The first microstrip patch is arranged on the top face of the first substrate, the second microstrip patch is arranged on the top face of the second substrate, the second microstrip patch is arranged between the first substrate and the second substrate, and the second substrate is arranged on the top face of the suppression plate; the first microstrip patch, the second microstrip patch, the first substrate and the second substrate are arranged in a 45 degrees inclined angle in an axial direction with the suppression plat. The device improves the the axial ratio, the impedance bandwidth, the stability of a phase center of the antenna, the signal receiving ability of a low elevation GNSS (Global Navigation Satellite System) and an ability to resist multipath interference, and the placing form of the antenna microstrip patch is more applicable to the actual handheld device application. By means of a combination way of a low insertion loss filter and a out-of-band high suppression filter, the noise figure is low and the antijamming capability is improved. The inside antenna and the outside arranged antenna have the advantages of being quick in switching speed, simple in operation and high in insulation.

The invention discloses a detection system for radio frequency performance of a repeater product, which comprises a control computer, a testing instrument unit, a signal control unit and tested equipment. The control computer is respectively connected with the testing instrument unit, the signal control unit and the tested equipment through communication cables, and is also connected with a printer through a data wire. A method for realizing the detection system comprises the steps of starting the detection system, calibrating the system, connecting the tested equipment, automatically testingvarious radio frequency indexes, saving test data, disconnecting the tested equipment, performing system inquiry, exporting a test report form, closing the detection system and so on. The detection system can automatically, accurately and quickly test performance indexes of the repeater product such as maximum gain, output power, in-band fluctuation, noise factor, transmission time delay and so on, and form a report form with a unified form to be convenient for the maintenance and management of engineering personnel.

A digital ultrasound beam former for ultrasound imaging, that can be configured by a control processor to process the signals from ultrasound transducer arrays with variable number of elements at variable sampling frequencies, where the lowest sampling frequency allows for the highest number of array elements. The maximal number of array elements is reduced in the inverse proportion to the sampling frequency. The beam former can be operated both in a RF-sampling mode and a quadrature mode. Parallel coupling of transmit / receive circuits for each element allow adaption of the receive Noise Figure and transmit drive capabilities to variations in the electrical impedance of the array elements.

The invention provides a high-linearity low-noise amplifier of the front end of an ultrahigh-frequency RFID (radio frequency identification) receiver. The amplifier detects two common levels from two differential output ends of a full-differential amplifier through a common-feedback circuit, bias current of the amplifier is adjusted validly and feedback voltage is outputted to a grid of a tail current source, and accordingly, overdrive voltage of the tail current source is increased, input current is increased and linearity is improved. Meanwhile, the problem of non-linear distortion caused by instability of the output common levels is solved. In addition, a coupling capacitor is crossed interstagely to increase power grain, and noise figure is reduced to improve noise performance. The high-linearity low-noise amplifier has the advantages of low noise figure, low power consumption, and high linearity, and solves the problem of carrier leak in ultrahigh-frequency RFID receivers and zero intermediate frequency receivers, and linearity of the low-noise amplifier is improved, so that weak available signals can be amplified linearly and distortionlessly in the process of receiving block signals.

Provided are a heating element that includes: a transparent substance; a conductive heating line that is provided on at least one side of the transparent substance; bus bars that is electrically connected to the conductive heating line; and a power portion that is connected to the bus bars, wherein 30% or more of the entire area of the transparent substance has a conductive heating line pattern that is formed of closed figures where a distribution is continuous and a ratio (area distribution ratio) of a standard deviation in respects to an average value of areas of the closed figures is 2% or more, and a method for manufacturing the same.

The invention provides an image wavelet denoising method based on median filtering, which belongs to the field of digital remote sensing image processing. In the method, median pre-filtering is firstly performed on images containing noise, wavelet conversion, threshold value treatment and denoising treatment are then carried out, wavelet reverse conversion is finally carried out, and filtered images are output. The invention has the advantages that the median filtering method is used for the pre-filtering of images containing noise, much noise of pepper salt type is removed, and influence on the high-frequency part of images is avoided; the wavelet threshold value method is then combined with the denoising method of the relativity of wavelet coefficient size, and the mixture of signal coefficient and noise coefficient caused by using the wavelet threshold value method singly is avoided; and meanwhile, a large amount of computation required by using the denoising method of the relativity of wavelet coefficient size singly is reduced. The experiments prove that the method has stable denoising effect and moderate computation amount.