377 results about "Channel filter" patented technology

A television (TV) receiver includes a multi-standard channel filter with a programmable intermediate frequency adapted to receive television signals in a variety of television standards and formats. In one embodiment, a receiver includes a tuner and a channel filter. The tuner receives input RF signals encoding information in one of a number of formats and converts the input RF signals to intermediate signals having an intermediate frequency (IF). The intermediate signals are coupled to the channel filter. The channel filter includes an anti-aliasing filter for filtering the intermediate signals, an analog-to-digital converter for sampling the filtered intermediate signals and generating a digital representation thereof, and a signal processor for processing the digital representation of the intermediate signals in accordance with the format of the input RF signal. The signal processor generates digital output signals indicative of information encoded in the input RF signal.

The invention discloses a satellite signal vector tracking method based on SINS/GPS deep integration data fusion. In the method, compensation is carried out on inertia element errors through channel filter information fusion, SINS/GPS deep integration navigation data fusion and an SINS system based on an SINS/GPS deep integration navigation system; and position and speed parameters of a current computation period are corrected to obtain accurate navigation parameters and generate local inference signals as well as keep the tracking for all visual GPS satellite signals; and a loop formed by channel filters and a main filter is utilized to complete the vector tracking and integration navigation information processing to the GPS satellite signals. The invention has excellent noise inhibitioncapacity and dynamic tracking performance, can ensure the navigation accuracy and the reliability of an integration system during the temporary interruption of the GPS satellite signals, and can maintain better pseudo code phase and carrier frequency tracking property in an environment with low carrier-to-noise ratio.

A transmitter/receiver in a base station comprises an antenna failure detection system including a receiving antenna for receiving a first signal from own station through a transmitting antenna and a second signal from another station, a channel filter for separating the first signal and the second signal, a detector for detecting the second signal, and a comparator for comparing the level of the detected signal, which is proportional to the coupling factor between the transmitting antenna and the receiving antenna, against a threshold to output an antenna failure signal based on the result of the comparison. The antenna failure detection system operates in a normal operation mode of the transmitter/receiver without reducing the number of service channels.

A radio frequency receiver front-end includes a low noise amplifier, a mixing stage, and a selectable channel filter. The low noise amplifier is operably coupled to amplify inbound RF signals to produce amplified inbound RF signals. The mixing stage is operably coupled to mix amplified inbound RF signals with a 1^st local oscillation to produce a 1^st intermediate frequency (IF) signal. The selectable channel filter is operably coupled to pass a 1^st channel of the 1^st IF signal when a channel select signal is in a 1^st state and to pass a 2^nd channel of the 1^st IF signal when the channel select signal is in a 2^nd state to produce a selected channel.

The invention proposes an incoherent frequency compensation and demodulation method and a demodulation device which have low power consumption, high performance and use the pseudo-randomness of the received signal phase and the PN code to realize the wireless digital communication data demodulation which has short distance, low power consumption and low packet loss rate through the carrier frequency error compensation and data recovery; the demodulation device is composed of a digital low-converter, a channel filter, a phase arithmetic unit, a phase differentiator, a frequency compensator and a PN code de-spreading correlator; the intermediate signal is converted into the plural baseband signals which are processed with channel outer band noise filtration so that the amplitude-time signal is converted into the phase-time signal; the phase differentiator is adopted to differentiate the phase-time signal; the frequency compensation circuit compensate the carrier frequency according to the phase difference signal and the phase average signal; the carrier frequency and the phase recovery circuit are avoided; the PN code correlator group processes the matching demodulation towards the semi-cosine shaping OQPSK and MSK signals of the DSSS directly to recover the baseband data; the incoherent frequency compensation and demodulation method and the demodulation device has the advantages of simple circuit, less quantity of hardware, easy low power consumption integration, good demodulation performance and being applicable to the wireless satellite navigation and the short-range wireless communication device with batteries as the power supply.

A Gaussian Frequency Shift Key (GFSK) receiver includes a receiver front end to receive a GFSK-modulated signal and convert the received GFSK-modulated signal to a baseband frequency modulated signal, a channel filter to reduce channel interference which is adjacent to a desired channel of the baseband frequency modulated signal, a demodulator to demodulate the channel filtered baseband modulated signal and to recover a sequence of symbols, a digital filter to reduce inter-symbol interference (ISI) from the sequence of symbols, a slicer to produce symbol decisions based on the filtered sequence of symbols, and a symbol-to-bit mapper to map the symbol decisions to data bits.

A low power, high performance circuit for magnitude and group delay shaping in continuous-time read channel filters is disclosed. The circuit generally comprises a first and a second biquadratic circuit, each having an input, a band pass, and a output low pass node, where the second biquadratic input node is coupled to the first biquadratic output node, and a first and second transconductor coupled to the first biquadratic band pass node and also to the second biquadratic band pass and low pass output nodes, respectively. The first and second transconductors are preferably programmable transconductors.

A multi-channel filter (20) includes S inputs for receiving S input signals (x₁ . . . x_S) and at least S filters (14, 28) coupled to the S inputs for filtering the input signals (x₁ . . . x_S) or auxiliary signals (y₁ . . . y_S) derived therefrom. The multi-channel filter (20) further includes a signal combiner (16) for combining the filtered signals into an output signal (ê) and a further signal combiner (22) coupled in between at least part of the inputs and at least part of the filters (14, 28). The further signal combiner (22) is arranged for combining at least part of the input signals (x₁ . . . x_S) into at least one auxiliary signal (y₁ . . . y_S) The multi-channel filter (20) is asymmetric in that at least one of the filters (28) has a filter length which is substantially larger than the filter lengths of the other filters (14). The asymmetric multi-channel filter combines a good convergence behavior with a low memory usage and can, for example, be used advantageously in multi-channel echo and noise cancellers.

A filter wheel having spirally shaped left and right channel 3D filters. The 3D filters are, for example, spectral separation filters. The filter is mounted, for example, close to an integrating rod output of a projector. The left and right channel filtered light scrolls across a modulation device which is energized with correspondingly scrolling left and right image data. In one embodiment, the integrating rod comprises mirrored surfaces to facilitate recycling of light reflected off the filter wheel. The filter wheel may be placed in a single or dual projector configuration. In one embodiment, the filters are fixed at the end of an integrating rod using “re-cycled” light to illuminate different channels of a projection system.

The invention discloses a partial flow equivalently-dynamic diluting and sampling system for diesel engine exhaust particles and a control method, belonging to the technical field of engine emission tests. The partial flow equivalently-dynamic diluting and sampling system is used for splitting the flow of engine exhaust with a constant ratio and introducing the engine exhaust in a diluting air duct by virtue of a flow-splitting and diluting pipeline with closed-loop feedback control, mixing the engine exhaust with clean air to form uniform diluted exhaust gas, introducing the diluted exhaust gas with a constant ratio in a sampling channel filter paper retainer by virtue of a particle sampling pipeline with closed-loop feedback control, collecting the exhaust particles by sampling filter paper placed in the retainer, and then detecting the emission level and the constituents of the diesel engine particles; the partial flow equivalently-dynamic diluting and sampling system can realize two-way transmission for data by an upper computer and a lower computer via an RS232 serial port communication protocol and a customized data format; and compared with the existing test system for diesel engine exhaust particles, the system has no need of a mass flow meter and an exhaust concentration analyser, and has the advantages of being high in control accuracy and low in test and maintenance costs.

A filter system includes a filter assembly and a filter element condition monitoring assembly. The filter assembly has a housing, a filter element disposed within the housing, an inlet passage extending through the housing, and an outlet passage extending through the housing, the outlet passage being connected to the inlet The passages are communicated via the filter element; the filter element condition monitoring assembly has an inlet pressure sensor connected to the inlet passage, an outlet pressure sensor connected to the outlet passage, and an outlet pressure sensor connected to the inlet pressure sensor and the outlet pressure sensor A microprocessor, the inlet pressure sensor measures inlet pressure in the inlet passage, and the outlet pressure sensor measures outlet pressure in the outlet passage. The microprocessor calculates the differential pressure between the inlet pressure and the outlet pressure, and calculates the condition of the cartridge state using at least one filter cartridge state parameter, which parameter may include the differential pressure.

The invention discloses a multi-band WIFI (wireless fidelity) parallel transmission scheme based on a waveguide tube transmission medium. According to the scheme, the waveguide tube transmission medium and WIFI access point equipment are utilized. The multi-band WIFI parallel transmission scheme is characterized in that a broadband combiner for injecting multi-channel WIFI access point equipment signals into the waveguide tube transmission medium, WIFI user equipment, channel filters and narrow-band antennas are also utilized, wherein the WIFI access point equipment is filtered via the channel filters and then is connected to the broadband combiner; and the WIFI user equipment receives the radiated signals in the waveguide tube transmission medium through the corresponding channel filters by the narrow-band antennas of the corresponding channels, the signals are radiated into the waveguide tube transmission medium, and the waveguide tube transmission medium transmits multi-channel WIFI signals in parallel. With the adoption of the multi-band WIFI parallel transmission scheme disclosed by the invention, interferences among different channels can be effectively reduced, and the simultaneous transmission of multi-channel frequency-orthogonal WIFI signals in a waveguide cavity can be realized, thus remarkably improving the utilization rate of the transmission medium, improving the transmission performance of a system, and reducing the construction and maintenance costs of the system.

The invention discloses a digital beam forming method of a broad band, which includes the steps of time division multiplexing quadrature sampling with intermediate frequency, quadrature demodulation, low pass filtering, interpolation delay, phase rotation and beam summation, etc. The beam forming method of the invention puts emphasis on that a single sample circuit is used for carrying out the time division multiplexing quadrature sampling with intermediate frequency on multipath bandpass signals; an FIR wave filter is used for completing the low pass filtering, the interpolation delay and the phase rotation which are matched with the signals at one time to realize the actual formation of delayed beams. As to the executive mode of wave filtering, a multi-channel wave filter with a cascade structure is disclosed. The wave filtering in the same path signal is completed in different filtering submodules by cascading while the different path signals share the same filtering module. The filtering output is completed with the sample selection, and the method of the invention is suitable for being realized in an ASIC or an FPGA and saves a great quantity of logic resources compared with the conventional wave filters.

A phase-based approach to estimating the frequency of complex sinusoids in the presence of noise that simultaneously reduces the threshold level and makes it frequency-independent. The approach relies on a filter bank approach: apply the signal to a highly overlapped, four-channel filter bank, detect which channel the signal is in, and apply a phase-based frequency estimation technique to the selected channel output. The computational complexity of the method is kept low by deriving a closed form for the resulting estimator and showing that it leads to an inherent decimation. Further improvement in performance can be obtained by cascading several stages of the four-channel filter bank; the performance tends toward that of the ML method as the number of stages increases.

The invention discloses a software radio-based ultra-wideband digital satellite beacon receiving method and a receiver. The receiver comprises an ultra-wideband radio frequency front end and a digitalsignal processing module, whose signals are mutually communicated, and a power supply module for providing power for the ultra-wideband radio frequency front end and the digital signal processing module, wherein the ultra-wideband radio frequency front end includes a variable gain amplifier, a quadrature mixer, a local oscillator, an I-channel amplifier, an I-channel filter, an I-channel ADC, anda Q-channel amplifier, a Q-channel filter and a Q-channel ADC; the digital signal processing module includes a frequency calculation module, a power calculation module, and a control interface module. According to the method and the receiver, a digital signal processing method, and self-adaptive frequency adjustment and gain adjustment are used for carrying out precise frequency and power calculation on a satellite beacon signal, and outputting frequency and power information to an antenna controller to form an antenna turntable driving command to complete the alignment satellite process. Themethod and the receiver have the advanteges of ultra-wideband operation, large dynamic range, high integration, stable and reliable performance, strong universality and the like.

A wireless communications receiving apparatus and a method for removing interference in a wireless communication system. The apparatus removes interferences and comprises a power detector, a channelization filter, a channel filter unit having a plurality of filters (e.g., including an all-pass filter, a low-pass filter and a high-pass filter), a plurality of interference power detectors corresponding to the plurality of filters, a channel filter selection block and a multiplexer. The power detector receives a digital signal and detects its power, the channelization filter selects a signal having a predetermined channel frequency from the received digital signal; the channel filter unit has a plurality of filters each for receiving and filtering the signal output from the channelization filter; each of the plurality of interference power detectors respectively receives a stored training signal and a training signal received within an output signal of a corresponding filter among the plurality of filters and calculates a plurality of corresponding interference powers; the channel filter selection block outputs a selection signal based on the power of the first signal; the interference powers calculated from the plurality of interference power detectors and a plurality of reference values; and the multiplexer selects any one from the output signals of the plurality of filters based on the selection signal.

A multiple diffusion channel filter assembly is disclosed. The filter assembly provides filtration of air entering and exiting an electronic enclosure through a breather hole. In one implementation of the invention the filter assembly contains a housing with an adsorbent component and a first diffusion channel and a second diffusion channel. The first diffusion channel is configured and arranged to provide fluid communication between the interior chamber of the housing and the inside of the electronic enclosure. The second diffusion channel is configured and arranged to provide fluid communication between the interior chamber of the housing and the exterior of the electronic enclosure. In another implementation of the invention the filter assembly contains a first layer and a second layer which surround an adsorbent component and a first and a second diffusion channel that are in fluid communication with the interior space defined by the first and second layers. In yet another implementation of the invention, a filter accessory containing a diffusion channel is configured to work in conjunction with a separate filter assembly thereby adding an additional diffusion channel to the existing design.

Disclosed is a frequency converter with an excellent frequency characteristic, having a minimized number of multipliers. A digital down-converter includes a decimator/mixer, an interpolator and a channel filter. The decimator/mixer performs quadrature conversion from a real signal to complex signals, frequency conversion by a frequency Kω, and 1/(M×I)-fold decimation on a signal obtained by sampling an RF/IF signal S(i) by an A/D converter. The interpolator is comprised of I-fold up-samplers and lowpass filters, and performs I-fold interpolation on the outputs from the decimator/mixer. The channel filter is comprised of lowpass filters having a band characteristic given to a communication channel, and outputs band-rejected baseband signals i(j) and q(j) by filtering the outputs of the interpolator.

A method and apparatus are presented for on-chip testing of circuits in testing channels. In an embodiment of the present invention, the system includes a weight selector that allows for a wide variety of weighting of test data that is to be supplied to the testing channels. For example, the weight selector may be used to weight all bits in all channels or individual bits in a particular channel. Clock control and diagnostic logic may also be provided to selectively supply scan, functional, and/or stop clock signals to the testing channels. Channel filtering logic may be also provided to mask output data from a selected testing channel as desired. The method and apparatus may provide improved testing performance and power savings.