Abstract: A compensating part compensates for deviations on transmission paths, and a pre-deviation signal combining part or a post-deviation signal combining part combines signals on the transmission paths before or after having the deviations applied thereto, wherein the compensating part performs compensation for the deviations based on output of the pre-deviation signal combining part or post-deviation signal combining part and the signals on the transmission paths to be compensated.

Abstract: An iterative method (400) and apparatus (200) for a receiver for reducing interference in a desired signal in a GSM communication system that use a finite-impulse-response filter combined with alternate quadrature component output selection for alternate linear equalization. The method includes inputting a burst of data of a received waveform including interference, training an alternate linear output filter with a midamble of known quadrature phase, providing an estimate of the desired signal by operating on the received waveform with the finite-impulse-response filter, generating log likelihood ratio estimates for a plurality of bits in the burst of data, selecting bits from the burst of data base upon a predetermined condition, and re-training the alternate linear output filter to provide a second improved estimate of the desired signal.

Abstract: The invention relates to an anti-demodulator circuit which is fundamentally built up in the same way as a demodulator circuit but, instead of a bandpass filter as generally used in a demodulator, comprises a notch filter which receives an input signal comprising a useful signal and an interference signal, and generates a filtered signal. The notch filter has a center frequency which approximately corresponds to the frequency of the input signal so as to suppress at least a part of the useful signal. The anti-demodulator circuit further comprises a mixer circuit which receives the filtered signal and a phase-shifted input signal and supplies a demodulated output signal which substantially corresponds to the interference signal.

Abstract: The invention relates to a method for implementing a transceiver, in which method radio-frequency signals are transmitted and received with a transceiver for communicating information. A radio-frequency signal received at a receiving stage is subjected to at least a first filtering step, in which a desired receiving signal is separated from the signal with a filter. A signal to be transmitted at a transmission stage is subjected to at least a second filtering step, in which a desired transmission signal is separated from the signal with a filter, to be transmitted. In the method, the same filter is used at least partly in said first and second filtering steps.

Abstract: Remotely controllable actuators are provided to alter the cavity size of bandpass cavity filters to alter the bandpass characteristics. In one embodiment, a stepper motor is used to provide lateral movement of a tuning plate to alter the size of the cavity. The neck of the cavity is also changed in length through the use of a tuning motor. A feedback loop is used to provide fine tuning of the length of the neck in response to changes due to temperature and vibration to offer maximum propagation of the signal to be transmitted. A coupling tuner is used to adjust to the resulting change in Q to the cavity. A tuning processor is used to receive signals from a remote location identifying the desired characteristics of the filter.

Abstract: A unique method for providing entertainment to a portable device, such as a wireless communication device, is disclosed. The method includes steps of receiving location information related to said wireless communication device; providing challenges associated with a game to a user of a wireless communication; providing rewards in response to answers based upon the location of said wireless communication device. The method finds particular application in vehicles having telematics communications products.

Abstract: A hearing compensation system for the hearing impaired comprises a plurality of bandpass filters having an input connected to an input transducer and each bandpass filter having an output connected to the input of one of a plurality of multiplicative AGC circuits whose outputs are summed together and connected to the input of an output transducer. The multiplicative AGC circuits attenuate acoustic signals having a constant background level without the loss of speech intelligibility. The identification of the background noise portion of the acoustic signal is made by the constancy of the envelope of the input signal in each of the several frequency bands. The background noise that will be suppressed includes multi-talker speech babble, fan noise, feedback whistle, florescent light hum, and white noise.

Abstract: An amplification circuit for a wireless base station is provided. The amplification circuit includes a first port adapted to communicate signals to and from an antenna and a second port adapted to communicate signals to and from a base station. The amplification circuit further includes a first path and a second path with each path coupled between the first and second ports. The first path includes at least one bandpass filter and an amplifier that pass and amplify upstream signals in a first frequency band. The second path includes a filter that stops upstream signals in the first frequency band and passes upstream signals in at least a second frequency band and downstream signals in at least third and fourth frequency bands.

Abstract: Outputs from respective elements of an array antenna 21 are demodulated, and the demodulated outputs are stored in storage means 29. The demodulated outputs are multiplied by tap coefficients of adaptive array antenna, then the multiplied outputs are combined by combining means 28, and the combined output is provided via a feed forward filter 22 to an adaptive equalizer 23, wherein it is equalized to obtain a decision symbol. During reception of a training signal the tap coefficients of adaptive array antenna and tap coefficients of the adaptive equalizer 23 are subjected to convergence processing by tap coefficient calculating means 24 so that an error signal becomes small, and then tap coefficients of the feed forward filter 22 and the adaptive equalizer 23 are subjected to convergence processing by tap coefficient calculating means 25 so that an error signal becomes small.

Abstract: A channel estimation apparatus for WCDMA mobile communication terminal is disclosed. The channel estimation apparatus includes a moving average filter for calculating the average value of pilot signals; an interpolator for computing a tentative estimation value of channel variation by using linear interpolation algorithms based on the average value of pilot signal; a channel compensator for compensating a channel variable of the data signal delayed in a predetermined time based on the tentative estimation value of channel variation; a decision block unit for tentatively determining data signal based on the compensated data signals; a raw channel estimator for computing a raw channel estimation value based on the output signal of the decision block unit and the data signal delayed; and a non-linear filter for computing a final channel estimation value of channel variation based on the tentative estimation value of channel variation and the raw channel estimation value.

Abstract: A method and device which dynamically detects, tracks and filters interfering signals with sufficient speed (i.e. within one IS-95 CDMA data. frame period, or 20 ms) and fidelity to eliminate or greatly reduce the deleterious effects of narrow band interferer signals on a CDMA link. When inserted in an RF signal path an Adaptive Notch Filter (ANF) detects narrow band interferors above a threshold level within the CDMA signal. Detection is accomplished by continuous scanning of a preset excision band, e.g. a specified narrow band associated with an AMPS system. Detected interferors are then automatically acquired and suppressed. This is achieved by electronically placing a rejection notch at the frequency of the interferors. Multiple notch filters may be used to simultaneously suppress multiple interferors. In the absence of interferors a bypass mode is selected allowing the RF signal to bypass the notch.

Abstract: A distributed antenna system in a communication system includes a programmable band pass filter at each antenna within the distributed system. Control information from a processor associated with the base station may instruct the band pass filter as to on which channels a particular antenna should transmit. In this manner, channel reuse may be promoted and channels can be dynamically reassigned during periods of peak usage.

Abstract: A baseband circuit having a transconductance filter (Gm-C filter) to receive a mixer signal. The Gm-C filter includes lossy integrators with coefficients for the filter to provide a filter frequency response that substantially replicates an ideal Gm-C filter.

Abstract: An amplification system for reducing DC offset in an input signal uses a low pass filter to isolate a DC component of the input signal. The system then subtracts the DC component from the input signal. In one embodiment, the system includes first and second amplifiers in addition to the low pass filter. The first amplifier amplifies the input signal to generate a first amplified signal at a differential output port of the amplification system. The second amplifier amplifies a low pass filtered version of the input signal to generate a second amplified signal at the differential output port of the amplification system. The outputs of the first and second amplifiers are connected to the differential output port of the amplification system in such a way that the first and second signals combine 180 degrees out of phase at the output port.

Abstract: A tuner for analogically and digitally modulated signals comprises a single tuner arrangement for converting any selected analog or digital channel to baseband or zero lF quadrature signals. Simple analog low pass filtering is applied before conversion in an ADC to the digital domain. A digital signal processor performs channel filtering and signal correction and supplies a signal to a digital demodulator. The processed digital signals are also supplied to a digital remodulator and DAC.

Abstract: A frequency down-converter (18) for a receiver (10) in a wireless telecommunications system. The down-converter (18) is capable of simultaneously processing a plurality of signal channels without increased signal distortion over a relatively wide bandwidth. The frequency down-converter (18) employs a suitable mixer (28), bandpass filter (32), attenuator (34) and transformer (36) that are tuned to provide the desired frequency down-conversion and amplitude control over the desired wideband width. In one embodiment, the bandpass filter passes a frequency band at 25 MHz or above. The frequency down-converter (18) generates the IF signal in a single step down-conversion process, or generates the IF signal and then a baseband signal in a two step down-conversion process.

Abstract: An equalizing device with notch compensation for a direct conversion receiver is disclosed. The baseband signal of a direct conversion receiver comprises a notch in the frequency response after the required DC compensation is performed. A bandpass generates a notch compensation signal on from a decision signal and a interference compensation signal of a decision feedback loop. Therefore, the reliability of the decision signal is enhanced and allows an improved data rate in WLAN applications.

Abstract: A SAW device includes two surface-acoustic-wave filter elements arranged so as to have a balanced-to-unbalanced conversion function. The surface-acoustic-wave filter elements include two first reflectors and two second reflectors. In each surface-acoustic-wave filter element, three IDTs are arranged on a piezoelectric substrate in a direction in which surface acoustic waves are transmitted so as to be positioned between one first reflector and one second reflector. The first reflectors differ in structure from the second reflectors.

Abstract: Multi-channel self-interference cancellation is provided in relayed electromagnetic communication between a first device and one or more other devices on one or more shared frequency channels. Specifically, near signals are generated at the first device and transmitted to a relay station. A composite signal is received at the first device from the relay station containing relayed versions of the near signals and relayed versions of remote signals transmitted from the one or more other devices, the composite signal having frequency channels including the one or more shared frequency channels, each shared frequency channel occupied by at least one of the relayed near signals and one of the relayed remote signals. One or more cancellation signals are selectively generated, each having a frequency band corresponding to one of the shared frequency channels. The cancellation signals are combined with the composite signal to produce a desired signal representing the relayed remote signals.

Abstract: A technique is provided for reducing power consumption of an internally powered console in an audio system through frequency based signal routing. A system employing the technique includes a base unit having an interface for receiving a signal representative of acoustic information. The base unit includes a filter system for splitting the signal into low-frequency and high-frequency component signals. The low-frequency signal is routed to a first audio driver for reproduction. The high-frequency signal is routed to a device that includes a second audio driver. By removing the need to reproduce the low-frequency portion of the acoustic information, the power consumption of the device is reduced.

Abstract: A multiple carrier adaptive notch filter (ANF) module selectively filters a received wideband communication signal to eliminate narrowband interference that lies within the frequency spectrum of the wideband communication signal. To determine the presence of narrowband interference, the multiple carrier ANF module scans various known narrowband channels that lie within the frequency spectrum of the wideband communication signal and determines signal strengths for each of the narrowband channels. The signal strengths from the narrowband channels are compared to a threshold that is derived from a statistical combination of the narrowband signal strengths. Narrowband channels having signal strengths that are greater than the threshold are determined to have interference.

Abstract: An amplification system for reducing DC offset in an input signal uses a low pass filter to isolate a DC component of the input signal. The system then subtracts the DC component from the input signal. In one embodiment, the system includes first and second amplifiers in addition to the low pass filter. The first amplifier amplifies the input signal to generate a first amplified signal at a differential output port of the amplification system. The second amplifier amplifies a low pass filtered version of the input signal to generate a second amplified signal at the differential output port of the amplification system. The outputs of the first and second amplifiers are connected to the differential output port of the amplification system in such a way that the first and second signals combine 180 degrees out of phase at the output port.

Abstract: A noise suppression apparatus for use in a receiver includes an input terminal adapted to receive an inbound signal. A channel splitter is coupled to the input terminal and configured to split the inbound signal into a substantially identical first signal and second signal. A first mixer coupled to the channel splitter and configured to receive the first signal, and a second mixer coupled to the channel splitter and configured to receive the second signal. A first local oscillator is coupled to the first mixer and configured to generate a first LO frequency signal, and a second local oscillator coupled to the second mixer and configured to generate a second LO frequency signal, where the first LO frequency signal and second LO frequency signal differ from one another.

Abstract: A radio receiver (100) has an IF (intermediate frequency) filter (200) for dynamically adjusting its intermediate frequency. The filter (200) includes a filter bank (301), power/amplitude estimator circuits (308, 310, 312), and weighting circuits (314, 316, 318). The filter bank (301) generates sub-bands, each sub-band having a predetermined frequency range. The power/amplitude estimators (308, 310, 312) provide an estimated power/amplitude in each sub-band. A filter control (320) uses the power/amplitude estimates to determine a percentage of each sub-band signal that is permitted to be coupled a summation circuit (319). The summation circuit (319) sums the weighted sub-band signals to provide a filtered output signal to a demodulator (212).

Abstract: A multiple carrier adaptive notch filter (ANF) module selectively filters a received wideband communication signal to eliminate narrowband interference that lies within the frequency spectrum of the wideband communication signal. To determine the presence of narrowband interference, the multiple carrier ANF module scans various known narrowband channels that lie within the frequency spectrum of the wideband communication signal and determines signal strengths for each of the narrowband channels. The signal strengths from the narrowband channels are compared to a threshold that is derived from a statistical combination of the narrowband signal strengths. Narrowband channels having signal strengths that are greater than the threshold are determined to have interference.

Abstract: In a cable television (CATV) data communication network, channel throughput and communications robustness are increased in a manner that improves speed of data transmission while maintaining compatibility with existing specifications and equipment. Enhanced throughput can be realized using the return channel of the CATV network. Alternatively, data retransmission and/or diversity techniques can be used to improve throughput.

Abstract: In a superheterodyne receiver, energy can bypass a filter by magnetically coupling to a metallic radio frequency shield. This is especially a problem with small form factor devices in which the metallic radio frequency shield is positioned close to the filter. By using a ferrite-embedded element positioned between the filter and the RF shield, some of the undesired harmonics produced by the mixer can be dissipated into heat.

Abstract: There is described a method and apparatus for separating two independently modulated co-channel interfering fm carriers. The method involves generating a numerator signal being a function of generating a numerator function and a denominator function, the numerator and denominator functions being themselves functions of the ratio of the interfering carrier to the wanted carrier and of the instantaneous difference between the frequency of the wanted carrier and the interfering carrier, and performing a division process between said denominator function and said numerator function to generate a quotient function and using said quotient function to condition an output circuit.

Abstract: A homodyne receiver is provided for receiving GSM and UMTS transmissions. The receiver may also be used for other transmission schemes. The receiver includes an electronically reconfigurable low pass filter and an off set generator for providing DC offset correction for offsets which may be generated as a result of coupling between a local radio frequency oscillator and the receiver front end.

Abstract: Comprising a magnetic member 32 formed by laminating magnetic sheets 24, 28, 30, 31 a first impedance element 21 formed in the magnetic member 32, and a second impedance element 25 formed above the first impedance element 21, the first impedance element 21 includes a first normal impedance element 22 and a first common impedance element 23, and the second impedance element 25 includes a second common impedance element 26 and a second normal impedance element 27.

Abstract: A multilayer LC filter includes a terminal layer, and a plurality of capacitor electrode layers laminated together on the terminal layer. An inductor layer is disposed above the capacitor electrode layers to thereby form a laminated body. First and second strip-shaped side-surface electrodes are formed on opposite side surfaces of the laminated body, and are connected to input and output terminals of the terminal layer, respectively. The distal ends of the first and second strip-shaped side-surface electrodes extend to the corresponding side surfaces of the capacitor electrode layers, but do not reach the side surfaces of the inductor layer. Thus, the distances between the resonator inductors of the inductor layer and the strip-shaped side-surface electrodes are increased, and as a result, very little stray capacitance is generated between the resonator inductors and the side-surface electrodes.

Abstract: A method of controlling a conference call in a system which comprises a conference bridge for combining several audio signals arriving from terminals and transmitting the combined signal further to at least one of the terminals. The method comprises detecting substantially simultaneously active predetermined audio signals, such as speech signals, in the audio signals of the conference bridge inputs and filtering the audio signals of the inputs with substantially different filters when there is more than one simultaneously active predetermined audio signal. The filtered audio signals are combined into one signal, and the combined signal is transmitted to at least one terminal.

Abstract: A technique is provided for reducing power consumption of an internally powered console in an audio system through frequency based signal routing. A system employing the technique includes a base unit having an interface for receiving a signal representative of acoustic information. The base unit includes a filter system for splitting the signal into low-frequency and high-frequency component signals. The low-frequency signal is routed to a first audio driver for reproduction. The high-frequency signal is routed to a device that includes a second audio driver. By removing the need to reproduce the low-frequency portion of the acoustic information, the power consumption of the device is reduced.

Abstract: According to the invention a digital signal path includes a first filter and an analog signal path includes a second filter. For analog reception both filters are connected in cascade, the first filter aiding the second filter in achieving a desired selectivity. Additional selection devices are obviated. Preferably the filters are surface acoustic wave filters.

Abstract: A direct conversion satellite tuner is fully integrated on a common substrate. The integrated tuner receives an RF signal having a plurality of channels and down-converts a selected channel directly to baseband for further processing. The integrated tuner includes on-chip local oscillator generation, tunable baseband filters, and DC Offset cancellation. The integrated tuner can be implemented in a completely differential I/Q configuration for improved electrical performance. The entire direct conversion satellite tuner can be fabricated on a single semiconductor substrate using standard CMOS processing, with minimal off-chip components. The tuner configuration described herein is not limited to processing TV signals, and can be utilized to down-convert other RF signals to an IF frequency or baseband.

Abstract: The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.

Abstract: The present invention discloses a method and apparatus for correcting the DC offset caused by self-conversion of the oscillator signal in an RF-to-baseband converter. The circuit comprises: a subtractor for subtracting an amplified DC offset signal from a filtered mixer signal to generate a corrected signal; a baseband amplifier coupled to the subtractor to receive the corrected signal to generate a baseband output signal; a low-pass filter coupled to the baseband amplifier to generate a DC offset signal representative of the DC offset; and a DC offset amplifier coupled to the low-pass filter and the subtractor to generate the amplified DC offset signal.

Abstract: A microphone, transmitter, speaker, receiver, and power source, all mounted to an eyeglasses frame, for sending and receiving signals wirelessly to and from a remote cell phone or other electronic device. The microphone and the transmitter can be mounted to extension arms that can be extended, pivoted, or otherwise moved to a position for use, and then moved to a stored position when not in use. Alternatively, the microphone, transmitter, speaker, receiver, and power source, can be mounted onto a clip-on or other attachment member that mounts onto a conventional eyeglasses frame, or to a hat or other article worn on the head.

Abstract: A method of excising one or more narrow-band interfering signals in a direct sequence spread spectrum receiver that performs a magnitude spectral analysis on baseband signals in a detection channel to determine which frequency bins in the spectral analysis output contain the interfering narrow-band signals by comparing the magnitude of the signals in the frequency bins to a threshold. The corrupted frequency bins are determined by the signal magnitudes exceeding the threshold and band reject filters excise the narrow-band signals in the signal channel in accordance with the corrupted frequency bins.

Abstract: A radio receiver (100) has an IF (intermediate frequency) filter (200) for dynamically adjusting its intermediate frequency. The filter (200) includes a filter bank (301), power/amplitude estimator circuits (308, 310, 312), and weighting circuits (314, 316, 318). The filter bank (301) generates sub-bands, each sub-band having a predetermined frequency range. The power/amplitude estimators (308, 310, 312) provide an estimated power/amplitude in each sub-band. A filter control (320) uses the power/amplitude estimates to determine a percentage of each sub-band signal that is permitted to be coupled a summation circuit (319). The summation circuit (319) sums the weighted sub-band signals to provide a filtered output signal to a demodulator (212).

Abstract: A circuit configuration having a filter, for example a bandpass filter, and a method for its operation are specified, which the circuit configuration allows for compensation of a frequency error, for example between an actual mid-frequency and a nominal frequency. A first mixer, upstream of the filter and a second mixer downstream from the filter are provided. A signal and a respective oscillation frequency are each supplied to respective inputs of the first and second mixers. The oscillation frequencies are mixed as a function of the frequency error in frequency generators such that the signal at the intermediate frequency is matched to the filter characteristics of the filter which is subject to tolerances. In consequence, filters that satisfy the stringent requirements for WCDMA mobile radio applications, but by virtue of the manufacturing technique, have an excessive mid frequency error, can be used, for example, in heterodyne receivers.

Abstract: A multipath noise reducer detects and removes the individual noise spikes occurring in an interval of multipath noise, thereby reducing the multipath noise with relatively little distortion of the output signal. The threshold signal used to detect multipath noise is varied depending on reception conditions. The gate pulses indicating the presence of multipath noise spikes are preferably expanded by variable amounts, depending on both reception conditions and the signal level. Multipath noise spikes are preferably replaced by a smoothed signal. These provisions further reduce perceived distortion of the audio output signal.

Abstract: Imager rejection circuitry includes a first digital path including a finite impulse response filter 202 having a variable gain stage 204 operable to apply a gain to a first digital signal in response to a coefficient selected from a coefficient table 206 and an adder 205 for summing the first digital signal to the output of the variable gain stage 205 to produce a corrected first digital signal. A second digital path processes a second digital signal and error calculation circuitry 207 determines an error between the first and second signals for selecting a coefficient from the coefficient table 206.

Abstract: The transmission system according to the invention comprises a transmitter (10) and a receiver (12). The transmitter (10) can transmit a multicarrier signal (11) to the receiver (12). The receiver (12) comprises an interference absorption circuit (20), which interference absorption circuit (20) comprises interference detection means (26) for detecting interference components, e.g. impulsive noise components, included in the multicarrier signal (11) and interference removal means (28) for substantially removing the interference components from the multicarrier signal (11). The interference detection means (26) are arranged for generating and supplying to the interference removal means (28) an interference presence signal (27) which is indicative of the presence of the interference components in the multicarrier signal (11).

Abstract: The invention relates to a cellular phone terminal system, and in particular to a method for changing timbre of a voice signal during conversation in a cellular phone terminal system having a filter for filtering a PCM input signal. The method comprises the steps of: waiting for a timbre selector key input for a desired timbre when a timbre converter key is inputted during conversation; and setting a filter coefficient of the filter correspondingly to the timbre selector key input and filtering the PCM signal to change timbre.

Abstract: A speech band signal is obtained by receiving a wireless frequency signal, a reception field intensity of the wireless frequency is detected on the basis of the resulting speech band signal, the frequency characteristics of the speech band signal so received are changed in accordance with the detection value of the detected reception field intensity, and a speech band signal having the frequency characteristics so changed is outputted.

Abstract: Method of suppression of narrow-band interferences attending at the receiver input added to the useful broadband signal and noise. There is a disclosed compensator rejecting narrow-band interferences by means of adjustment loops. Two general methods of construction of such loops are considered. The first general method is based on filtration of the in-phase and quadrature components of the error vector—difference of the interference vector and compensating vector. The second method is based on filtration of the amplitude and full phase of the interference signal. Automatic tuning of the compensator to the mean frequency and effective interference band is ensured.

Abstract: In one embodiment, an apparatus comprising a mixing network coupled to a summing stage is presented. The mixing network is operative to receive a signal and process the received signal along a first branch of the mixing network to produce a first mixed signal containing an image signal, and along a second branch of the mixing network to produce a second mixed signal containing the image signal and a desired signal. The summing stage, coupled to the first and second branch of the mixing network, is operative to subtract the first mixed signal from the second mixed signal to produce a downconverted signal comprising the desired signal while rejecting the image signal.

Abstract: A receiver is provided in which a composite signal is split into two paths. In the first path, a desired signal channel is suppressed by a notch filter. The remaining channels in the composite signal are inverted. In the second path, the signal is delayed to match the delay imposed by the first path. The signal from the first path is recombined with the second path, which reduces the signal level of the undesired channels to the level of quantization noise. The desired signal can then be amplified using the full dynamic range of the amplifier circuitry. If desired, more than one channel may be received at a time. Further, if the two or more channels that are being received have different signal strengths, the digital filtering functions of the notch filter can be used to selectively weight the signals to equalize their strengths. In addition, channels of different bandwidths can be received.

Abstract: A selective call receiver unit (100) having a post detection filtering system optimized for both simulcast delay spread and receiver sensitivity includes a receiver (20), a detector (30) for detecting a message and providing a detected signal, a first post detection filter (40) for filtering the detected signal and further being optimized for sensitivity providing a first filtered signal, and a second post detection filter (41) for filtering the detected signal and further being optimized for simulcast delay spread providing a second filtered signal. In addition, a combiner 45 is used for selectively combining the first filtered signal with the second filtered signal.