Abstract: A gain stage includes an offset cancellation loop coupled to a first amplifier. The first amplifier has a first transfer function and a first gain, and the offset cancellation loop includes a second amplifier having a second transfer function and a second gain. The second transfer function is based on an inverse of the first transfer function and the second gain based on an inverse of the first gain. When the offset cancellation loop feeds back an output signal of the first amplifier to an input of the first amplifier, a high-pass pole (or high-pass corner frequency) of the first amplifier is maintained at a constant level in spite of variations in the gain of the first amplifier. In one case, the second amplifier in the offset cancellation loop may be a simpler and lower power version of the first amplifier.

Abstract: A method for detecting a primary synchronization is provided. The method includes: obtaining a time-domain signal sequence for synchronization; obtaining a correlation result corresponding to the time-domain signal sequence; normalizing the correlation result according to a received signal strength indicator corresponding to the time-domain signals; and sorting the normalized correlation result to ascertain a peak value position corresponding to the correlation result.

Abstract: A wireless communication receiver includes a multitude of look-up tables each storing a multitude of DC offset values associated with the gains of an amplification stage disposed in the wireless communication receiver. The entries for each look-up table are estimated during a stage of the calibration phase. During such a calibration stage, for each selected gain of an amplification stage, a search logic estimates a current DC offset number and compares it to a previous DC offset estimate that is fed back to the search logic. If the difference between the current and previous estimates is less than a predefined threshold value, the current estimate is treated as being associated with the DC offset of the selected gain of the amplification stage and is stored in the look-up table. This process is repeated for each selected gain of each amplification stage of interest until the look-up tables are populated.

Abstract: Apparatus and methods disclosed herein perform gain, clipping, and phase compensation in the presence of I/Q mismatch in quadrature RF receivers. Gain and phase mismatch are exacerbated by differences in clipping between I & Q signals in low resolution ADCs. Signals in the stronger channel arm are clipped differentially more than weaker signals in the other channel arm. Embodiments herein perform clipping operations during iterations of gain mismatch calculations in order to balance clipping between the I and Q channel arms. Gain compensation coefficients are iteratively converged, clipping levels are established, and data flowing through the network is gain and clipping compensated. A compensation phase angle and phase compensation coefficients are then determined from gain and clipping compensated sample data. The resulting phase compensation coefficients are applied to the gain and clipping corrected receiver data to yield a gain, clipping, and phase compensated data stream.

Abstract: Embodiments of the present invention may provide a signal processor with a wide gain range. The signal processor may comprise at least a discrete step gain stage and a continuous variable gain amplifier (VGA) stage. The discrete step gain stage may comprise a programmable gain amplifier (PGA) (e.g., low noise amplifiers 1 and 2 (LNA1 and LNA2)). The VGA stage may provide a continuous range to compensate the LNAs gain steps. In one embodiment, the AGC controller enables an inherent hysteresis with the AGC step change if required.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: Provided are a receiving apparatus and method for a wireless communication system using multiple antennas. A receiving method for a wireless communication system using multiple paths, the receiving method comprising: receiving signals through a predetermined number of multiple paths; sensing a carrier according to saturation state degrees of the signals, and providing saturation state information; calculating automatic gain components of the received signals by using the received signals and the saturation state information of the received signals; and performing a noise matching process to amplify noises on the predetermined multiple paths according to the automatic gain components during a predetermined period.

Abstract: A gain control circuit adjusts the signal level of a received signal responsive to the bandwidth a received signal and/or the delay spread of the channel in which the signal has propagated. The bandwidth and delay spread are evaluated to estimate the amount of signal variation that is expected due to fast fading. Adjustments to the signal level are then made to avoid clipping while at the same time ensuring that the dynamic range of a receiver component is efficiently utilized.

Abstract: A test system (200) for testing for missing or shorted parts within a tuner circuit includes a signal generator (202) for applying a harmonic-containing baseband time varying RF test signal to the tuner circuit. The tuner circuit is tuned to a harmonic of test signal. A detector 208 coupled to the baseband IF output of the tuner circuit detects the voltage generated in response to the applied RF test signal. A voltage measurement device (210) measures voltage detected by detector to provide an indication of the gain. Significant changes in the gain indicate missing part(s) or short circuits.

Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

Abstract: A method and an apparatus for reducing Digital-to-Analog Conversion (DAC) bits at a transmitter of a Frequency Division Multiple Access (FDMA) system reduces a number of the bits for conversion so as to save power and reduce the cost of operation. The method can include generating a digital signal gain control value and an analog signal gain control value using subcarrier allocation information, a required Signal to Noise Ratio (SNR), and a Peak to Average Power Ratio (PAPR); controlling a gain of a signal input to a digital-to-analog converter using the digital signal gain control value; converting a digital signal of the controlled gain to an analog signal using the digital-to-analog converter; and restoring an original signal by controlling a gain of a signal output from the digital-to-analog converter using the analog signal gain control value.

Abstract: The invention teaches a solution, for example, for Long Term Evolution (LTE) networks. The solution comprises determining a measurement pattern for at least one automatic gain control tracking loop when resource restrictions have been configured for a user equipment, the resource restrictions comprising at least one measurement restriction pattern, wherein each automatic gain control tracking loop is associated with at least one measurement restriction pattern; and performing automatic gain control measurements according to the measurement patterns of the at least one automatic gain control tracking loop.

Abstract: One embodiment of the present subject matter includes a method of receiving an input signal. The method, in various embodiments, includes detecting a peak of the input signal and detecting an envelope of the input signal. In various embodiments, the peak and envelope are used to identify out-of-band blocking signals and to adjust gain control. The method also includes comparing the peak to a first threshold Tp and comparing the envelope to a second threshold Te. In the method, if the peak is above the first threshold and the envelope is below the second threshold, then ignoring the input signal. If the envelope is above the second threshold, the method includes applying automatic gain control to decode information encoded in the input signal.

Abstract: A direct-conversion radio receiver is provided. The receiver includes a first measurement unit configured to measure a signal level of a received signal at an input of the receiver. The receiver also includes a gain controller configured to stepwise adjust at least a front-end gain and a baseband gain of the receiver when the signal level of the received signal at the input of the receiver exceeds a given sensitivity level, and adjust the front-end gain with at least one further gain step when the input signal level is below the given sensitivity level.

Abstract: An antenna module with a detector and an associated canceller is disclosed. The detector may also detect interference and spurs. In one embodiment, an antenna module can include: an antenna configured to receive an electromagnetic signal in a signal path; an amplifier configured to amplify the received electromagnetic signal, and to provide the amplified signal at a first node; a filter configured to receive the amplified signal from the first node, and to provide a filtered signal output therefrom; and a noise canceller and a detector integrated in the signal path at the first node.

Abstract: Systems and methods which provide a multimode tuner architecture implementing direct frequency conversion are shown. Embodiments provide a highly integrated configuration wherein low noise amplifier, tuner, analog and digital channel filter, and analog demodulator functionality are provided in a single integrated circuit. A LNA of embodiments implements a multi-path configuration with seamless switching to provide desired gain control while meeting noise and linearity design parameters. Embodiments of the invention implement in-phase and quadrature (IQ) equalization and a multimode channelization filter architecture to facilitate the use of direct frequency conversion. Embodiments implement spur avoidance techniques for improving tuner system operation and output using a clock signal generation architecture in which a system clock, sampling clock frequencies, local oscillator (LO) reference clock frequencies, and/or the like are dynamically movable.

Abstract: A television signal processing apparatus comprising a receiver comprises a distortion estimator and an automatic gain control signal generator. The automatic gain control signal generator generates a plurality of automatic gain control and filter response control signals in response to the magnitude or signal to noise ratio of an RF signal and a non-linear distortion figure generated from the information carried by said RF signal. The distortion estimator uses a plurality of statistical methods to generate a non-linear distortion figure from the signal constellation of the information carried by said RF signal.

Abstract: A method for use in a digital communications receiver for controlling an input signal level (200) into an analog-to-digital converter (ADC) initially receives a sample sequence (201) where a threshold crossing rate is measured as a percentage samples of an input signal that exceed the threshold (203). The error between the measured threshold crossing rate and a desired reference threshold crossing rate is calculated (205) and an error signal is then utilized in a feedback loop to control the receiver gain such that the error is reduced (207).

Abstract: Provided are apparatus and method for receiving signals in a wireless communication system.

Abstract: A method for digital compensation of nonlinearities in a communication system that includes a transmitter, a transmission channel and a receiver, including: estimating the nonlinearities induced by the transmitter and/or the receiver, from at least one learning sequence received at the receiver and distorted by the nonlinearities, and compensating for the nonlinearities distorting a signal received at the receiver based on the estimating of the nonlinearities.

Abstract: Techniques for scaling symbols to account for large abrupt changes in received power at a user equipment (UE) are described. The UE performs AGC on received samples to obtain input samples. The UE processes (e.g., CDMA demodulates) the input samples to obtain first symbols. The UE determines the power of the input samples and derives a symbol gain based on (e.g., inversely related to) the power of the input samples. The UE scales the first symbols with the symbol gain to obtain detected data symbols having approximately constant amplitude, even with large abrupt changes in the power of the input samples. The UE estimates signal amplitude and noise variance based on the detected data symbols, computes LLRs for code bits of the detected data symbols based on the signal amplitude and noise variance, and decodes the LLRs to obtain decoded data.

Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.

Abstract: One embodiment of the present subject matter includes a method of receiving an input signal. The method, in various embodiments, includes detecting a peak of the input signal and detecting an envelope of the input signal. In various embodiments, the peak and envelope are used to identify out-of-band blocking signals and to adjust gain control. The method also includes comparing the peak to a first threshold Tp and comparing the envelope to a second threshold Te. In the method, if the peak is above the first threshold and the envelope is below the second threshold, then ignoring the input signal. If the envelope is above the second threshold, the method includes applying automatic gain control to decode information encoded in the input signal.

Abstract: A frequency synthesizer includes: a frequency source generating a reference signal that includes a plurality of pulses having periodicity based on a reference frequency; a feedback loop that includes, a phase detector circuit, a loop filter, a controlled oscillator that generates an output signal at an output, and a loop divide circuit; a non-linear circuit element at an input of the phase detector circuit, which generates intermodulation distortion that causes at least one spurious signal at the output; and a controller controlling the loop divide circuit and the non-linear circuit element. The frequency synthesizer further includes a dither circuit that adjusts the timing of some of the pulses of the reference signal based on a parameter provided by the controller to the non-linear circuit element, thereby, providing a jittered reference signal to the non-linear circuit element for attenuating the at least one spurious signal at the output.

Abstract: A Radio Frequency (RF) receiver includes a low noise amplifier (LNA) and a mixer coupled to the output of the LNA. The gain of the LNA is adjusted to maximize signal-to-noise ratio of the mixer and to force the mixer to operate well within its linear region when an intermodulation interference component is present. The RF receiver includes a first received signal strength indicator (RSSI_A) coupled to the output of the mixer that measures the strength of the wideband signal at that point. A second received signal strength indicator (RSSI_B) couples after the BPF and measures the strength of the narrowband signal. The LNA gain is set based upon these signal strengths. By altering the gain of the LNA by one step and measuring the difference between a prior RSSI_B reading and a subsequent RSSI_B? reading will indicate whether intermodulation interference is present.

Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.

Abstract: A linearizer for reducing intermodulation distortion in a non-linear device. The novel linearizer includes an input port for receiving a signal from the device and a circuit for effecting gain expansion on the signal that counteracts a gain compression of the device. In an illustrative embodiment, the circuit includes a starved limiter in shunt with the device, implemented using a pair of biased diodes D1 and D2. The first diode D1 is connected to ground and the second diode D2 is coupled to the signal. In an alternate embodiment, the linearizer also includes a second pair of biased diodes D3 and D4, D3 connected to ground and D4 coupled to the signal, and a plurality of reactive elements for increasing the operational bandwidth of the linearizer.

Abstract: The invention provides a radio frequency signal receiver with adequate gain control path to control the gain of a mixer and/or a channel selection filter, comprising a low noise amplifier for receiving and amplifying a radio frequency signal, a local oscillator (LO) for providing a LO signal, a mixer for down converting the radio frequency signal by the LO signal to an intermediate signal, a channel selection filter for receiving and filtering the intermediate signal to develop an output signal, and an automatic gain control unit for feedback adjusting the gain of the low noise amplifier and forward controlling the gain of the mixer and channel selection filter in accordance with the output signal of the low noise amplifier.

Abstract: One embodiment of the present subject matter includes a method of receiving an input signal. The method, in various embodiments, includes detecting a peak of the input signal and detecting an envelope of the input signal. In various embodiments, the peak and envelope are used to identify out-of-band blocking signals and to adjust gain control. The method also includes comparing the peak to a first threshold Tp and comparing the envelope to a second threshold Te. In the method, if the peak is above the first threshold and the envelope is below the second threshold, then ignoring the input signal. If the envelope is above the second threshold, the method includes applying automatic gain control to decode information encoded in the input signal.

Abstract: Methods and apparatus for digital jammer detection. In an aspect, a method is provided for detecting a jammer in a received waveform. The method includes filtering the received waveform to produce a filtered waveform and subtracting the filtered waveform from the received waveform to produce a difference waveform. The method also includes determining a power differential associated with the difference waveform, and detecting the jammer if the power differential exceeds a selected threshold. In an aspect, an apparatus is provided that includes a filter configured to filter the received waveform to produce a filtered waveform and combining logic configured to subtract the filtered waveform from the received waveform to produce a difference waveform. The apparatus also includes power determination logic configured to determine a power differential associated with the difference waveform, and decision logic configured to detect the jammer if the power differential exceeds a selected threshold.

Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.

Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.

Abstract: An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined.

Abstract: In order to avoid disappearance of output symbols in accompaniment with DC voltage fluctuations occurring at the timing of switching gain in receiving systems for mobile telephones or the like compatible with W-CDMA systems, the present invention provides a variable gain amplifier circuit, a gain control circuit and a mobile communication terminal apparatus, in which a PGA section is comprised of PGAs having different amplification widths continuously arranged in plural stages as in, two coarse adjustment PGAs, a fine adjustment PGA and a coarse adjustment PGA from the input side to the output side; and a gain control circuit has a memory storing a history of gain control with regard to the PGA section and a logic circuit individually controlling gain of each PGA.

Abstract: An apparatus and method to use a gain control network across source terminals of cascode transistors that drive a differential current to control gain. The drains of the cascode transistors are coupled to a load such as a mixer. The cascode arrangement provides high impedance coupling to the load and the proximity of the gain control network allows offsets to be gain tracked to signal gain.

Abstract: A level detector includes a comparing circuit and an integrating circuit. The comparing circuit generates pulses each having its width corresponding to the length of a time period during which the strength of an input signal is higher than a reference value. Alternatively, the comparing circuit may generate pulses each having its width corresponding to the length of a time period during which the strength of the input signal is lower than the reference value. The comparing circuit successively outputs the pulses. The integrating circuit outputs a signal having its strength corresponding to an integration value obtained by temporally integrating the signal from the comparing circuit.

Abstract: An automatic gain controller having an estimator to estimate the level of an input signal, a subtractor to calculate a difference between the level estimated by the estimator and a predetermined reference value, a gain controller to output a control value achieved by scaling non-linearly the difference output by the subtractor, an accumulator to accumulate the output of the gain controller, and a modulator to modulate the output of the accumulator to a pulse width modulated signal. The gain controller outputs the control value proportional to a square of the difference. If en error between the power of the input signal and the reference value is great, the power can be quickly adjusted to a desired signal level, and if the error is small, the gain can be controlled finely.

Abstract: A method and apparatus for recovering a data symbol from a communication signal in which the communication signal is processed to produce a baseband waveform that is then sampled to obtain a channel sequence. The channel sequence is decoded to obtain an estimate of the data symbol together with a measure of the reliability of the data symbol. The processing of the communication signal is adjusted dependent upon the measure of the reliability of the data symbol. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: An AGC circuit controls LNA and VGA amplifiers such that a received signal is converted at a high speed with tracking errors prevented according to each modulation scheme. The AGC circuit generates LNA and VGA control signals controlling the LNA and VGA amplifiers, respectively. A digital signal, converted from the received signal, is calculated for a power value, on which scaling is performed by a scaling section to then be provided through an adder and a register to a control signal generator for generating the LNA and VGA control signals. The scaling section compares the power value with a target value to perform scaling with a scaling coefficient according to the sign of the comparison value so that an increase of the tracking error is avoided, thus preventing phenomena where the AGC control oscillates without convergence, thereby making it possible to attain the optimum automatic gain control.

Abstract: A transmission power control method includes a step (a) of receiving by a receiver a radio wave signal, a step (b) of judging whether a first identification signal is included in the received radio wave signal, a step (c) of detecting a reception electric field intensity of the radio wave signal included in the radio wave signal in the case where the first identification signal is included in the radio wave signal, a step (d) of obtaining a radio wave propagation state between a home station and the station to communicate with by using the reception electric field intensity detected at the step (c) and determining transmission power of the transmission radio wave signal based upon the radio wave propagation state, a step (g) of invalidating the radio wave propagation state obtained upon the previous reception in the case where the interval between an end of communication and a restart of communication is longer than a time determined in advance, a step (e) of superimposing a second identification signal on th

Abstract: An RF switch is disclosed. Power of an amplifier installed in an RF switch of a TV receiver is adjusted by using a Schmitt trigger circuit. If an output voltage of an RF automatic gain controller of a tuner is greater than a pre-set upper limit threshold value, the amplifier is turned on, whereas if an output voltage of an RF automatic gain controller of a tuner is smaller than a pre-set lower limit threshold value, the amplifier is turned off. Thus, a signal distortion phenomenon that may occur when an infinitesimal signal, a strong signal and several signals with high power levels are adjacent to each other can be avoided, so a performance of a receiving unit is improved.

Abstract: Disclosed is an AGC (automatic gain control) device and method of an OFDM system with a DC offset compensation function, and a recording medium storing a program including the method. The AGC device calculates an energy of input signals with DC offsets as the summation of the square of the input signals, and calculates an energy of the DC offsets in the input signals as the summation of the square of the DC offsets. Pure signal energy without DC offsets is produced by subtracting the energy of the DC offsets from the energy of the calculated input signal. The energy and an AGC reference value are then compared, and feedback of a comparison result is performed.

Abstract: An automatic gain controller (AGC) and method for use in a digital TV receiver having an IF amplifier, an RF amplifier, an analog to digital converter (ADC) connected to the IF amplifier, and a demodulator connected to the ADC, the AGC comprising: an input selector for selecting as feedback signal one of a digitized IF signal output of the ADC and a demodulated signal output of the demodulator; a signal detection unit for detecting the conditions of the feedback signal and outputting status signals; and a traffic controller for receiving the status signals and outputting control signals based on the status signals to an IF gain controller and an RF gain controller for independent gain control of the RF amplifier and the IF amplifier. The AGC and method further including hysteresis-curve-based switching for alternatively halting adjustments to IF gain while adjusting RF gain or halting adjustments to RF gain while adjusting IF gain.

Abstract: An apparatus and method for compensating the gain of an Automatic Gain Controller (AGC) for stabilizing the reception power of discontinuously transmitted packet data in a mobile communication system are disclosed. A compensation controller receives an AGC value from the AGC, sampling the AGC value by a predetermined sample number for a predetermined period, and obtains an AGC compensation gain by comparing a predetermined value with the difference between a sampled AGC value with a reference gain for the predetermined period. A compensator compensates the AGC value with the AGC compensation gain, thereby correcting errors generated in view of the nature of the AGC.

Abstract: An arrangement for decoding a stereo multiplex signal, comprising a baseband sum signal (L+R), a difference signal (L?R) which is amplitude-modulated on a suppressed sub-carrier and a pilot signal having a frequency located between the frequency bands of said sum and difference signals, said arrangement having an input for the stereo multiplex signal coupled through parallel stereo sum and difference signal paths to first and second inputs of a dematrix circuit, a synchronous demodulator being included in the difference signal path, a local sinusoidal sub-carrier being supplied to a carrier input of said synchronous demodulator for a synchronous demodulation of said amplitude-modulated difference signal (L?R) into baseband.

Abstract: Disclosed is a novel and improved dynamically programmable linear receiver which provides the required level of system performance with reduced power consumption. In one embodiment, disclosed is a programmable receiver coupled to a jammer detector for detecting the presence of jamming in an RF signal, the jammer detector coupled to a state machine, and the state machine having means for controlling the receiver based on the results of the jammer detector detecting the presence of jamming in the RF signal. The disclosed receiver is capable of detecting the presence of jammers, with a means to adjust the bias current downward if no jammers are present, which improves the receiver's standby time and prolongs battery life.

Abstract: A Radio Frequency (RF) receiver includes a low noise amplifier (LNA) and a mixer coupled to the output of the LNA. The gain of the LNA is adjusted to maximize signal-to-noise ratio of the mixer and to force the mixer to operate well within its linear region when an intermodulation interference component is present. The RF receiver includes a first received signal strength indicator (RSSI_A) coupled to the output of the mixer that measures the strength of the wideband signal at that point. A second received signal strength indicator (RSSI_B) couples after the BPF and measures the strength of the narrowband signal. The LNA gain is set based upon these signal strengths. By altering the gain of the LNA by one step and measuring the difference between a prior RSSI_B reading and a subsequent RSSI_B? reading will indicate whether intermodulation interference is present.

Abstract: A method of controlling operation of a wireless device configured in a zero intermediate frequency architecture including a DC loop and a gain loop. The method includes processing energy in a wireless medium to generate a corresponding receive signal, monitoring the receive signal via a predetermined measurement window, detecting a changed condition in the channel, holding the gain feedback control loop at a constant gain level, and operating the DC loop in an attempt to search a stable DC value for the receive signal while the gain loop is held constant. A first case is DC saturation, where the gain is held constant until DC is controlled. A second case is clear channel assessment, where a prior stored gain setting is applied to the gain loop after detecting the end of the packet. A third case is preparation for receiving an expected acknowledgement packet after transmitting a packet, where again a prior stored gain setting is applied to the gain loop and DC is searched.