Abstract: A radio frequency transmitter includes a transmit circuit configured to generate a transmit signal; a receive band rejection filter comprising a capacitor and an inductor resonating with each other to reject a receive frequency band from the transmit signal, wherein a ratio value of a capacitance value of the capacitor to an inductance value of the inductor is within a predetermined range; and a power amplifying circuit configured to amplify the transmit signal through the receive band rejection filter.

Abstract: A device for the detection of an ultra wide band signal, including a signal reception circuit, a signal divider circuit to divide the received signal into several frequency sub-bands, a circuit to determine the amplitude and duration of the received signal in each frequency sub-band, a circuit to compare the amplitude of the signal received in each frequency sub-band with an amplitude threshold, a circuit to compare the duration of the signal received in each frequency sub-band with a time threshold, and a decision circuit that determines that the received signal is of the ultra wide band type if the amplitude of the signal received in each frequency sub-band is higher than the amplitude threshold and if the duration of the signal received in each frequency sub-band is less than the time threshold.

Abstract: A charging device for an electric vehicle includes a wireless power receiving device which receives high-frequency AC power in a non-contact state, a wired power receiving device connected to an external power source for low-frequency AC power, a rectifier which rectifies AC power, an electric power converter which is positioned at a rear part of the rectifier, and an power receiving device switching switch which switches electric power in such a way that any of electric power of both electric power receiving devices is outputted to the rectifier. A high-frequency filter, which removes a high-frequency component, is provided between the rectifier and the electric power converter.

Abstract: A ladder-type filter includes: one or more series resonators connected in series between an input terminal and an output terminal; two or more parallel resonators connected in parallel between the input terminal and the output terminal; and a path that electrically connects ground terminals of the two or more parallel resonators to each other, electrically connects to ground through only a ground terminal of a parallel resonator located closest to the input terminal or to the output terminal, and includes at least two inductors connected in series in at least two positions of positions between the ground terminals of the two or more parallel resonators and a position between the ground terminal of the parallel resonator located closest to the input terminal or to the output terminal and the ground.

Abstract: Methods and apparatus for operating an internal combustion engine are provided. The engine has an engine block defining a cylinder accommodating a reciprocating piston coupled to rotate a crankshaft, a fuel injector for injecting fuel inside the cylinder, and a crank position sensor positioned proximal to the crankshaft. A method includes commanding the fuel injector to perform a test fuel injection with a predetermined energizing time and using the crank position sensor to determine a crankshaft acceleration signal during the test fuel injection. The crankshaft acceleration signal is filtered and a value of an amplitude of a fundamental frequency component of the filtered crankshaft acceleration signal is determined. A correction factor of the predetermined energizing time is determined based on a difference between the determined value of the amplitude and a preset value thereof. The correction factor is used to correct an energizing time of subsequent fuel injections.

Abstract: An integrated circuit is disclosed. The integrated circuit includes an amplifier and a capacitor array coupled to the amplifier. The capacitor array is configured to be coupled in parallel to an inductor that is external to the integrated circuit, and the capacitor array and the external inductor comprise a tank circuit. The integrated circuit includes a resistor array coupled in parallel with the capacitor array. The resistor array is utilized to provide an overall frequency response of the capacitor array and resistor array that is opposite of a frequency response of the external inductor over a predetermined frequency range.

Abstract: An integrated receiver includes a first signal processing path, a second signal processing path, and a controller. The first signal processing path has an input and an output for providing a first processed signal, and comprises a first tracking bandpass filter having a first integrated inductor formed with windings in a first number of metal layers of the integrated receiver. The second signal processing path has an input and an output for providing a second processed signal, and comprises a second tracking bandpass filter having a second integrated inductor formed with windings in a second number of metal layers of the integrated receiver. The second number of windings is lower than the first number. The controller enables one of the first and second signal processing paths corresponding to a selected channel of a radio frequency (RF) input signal to provide an output signal.

Abstract: A wireless communication device includes a demodulation unit which demodulates a predetermined reception frequency, an S/N improvement processing unit which performs an S/N improvement process on a demodulated signal output from the demodulation unit, a first filter which performs an adaptive operation with respect to a frequency having a largest amplitude in a signal output from the S/N improvement processing unit, and outputs a filter coefficient updated by the adaptive operation, a controller which calculates the frequency of the largest amplitude defined by the filter coefficient output from the first filter, and controls the demodulation unit to update the reception frequency so as to reduce a difference between the frequency having the largest amplitude and a predetermined frequency, and a second filter which limits a range of a frequency bandwidth of the demodulated signal based on the frequency having the largest amplitude.

Abstract: Embodiments of apparatuses, systems and methods relating to temperature compensation of acoustic resonators in the electrical domain are disclosed. Other embodiments may be described and claimed.

Abstract: A method and apparatus for efficient network scanning that selects candidate frequencies based upon the frequency bands that were noted as being active during a previous network scan. A mobile device performs a full network scan on power up or on radio cycle and determines the available active bands. This information is stored as active band information on the device. When the device loses coverage on a selected one of the bands, then it identifies a candidate frequency based upon the stored active band information and attempts to locate a suitable network on the candidate band.

Abstract: In one embodiment, the present invention includes a mixer circuit to receive and generate a mixed signal from a radio frequency (RF) signal and a master clock signal, a switch stage coupled to an output of the mixer circuit to rotatingly switch the mixed signal to multiple gain stages coupled to the switch stage, and a combiner to combine an output of the gain stages.

Abstract: A method includes receiving an input signal carrying transmitted values by a receiver, which includes a decision device that produces estimates of the transmitted values. The input signal is filtered using a forward filter to produce a forward-filtered signal, and the estimates of the transmitted values are filtered using a backward filter to produce a backward-filtered signal. The decision device is applied to a composite signal produced from the forward-filtered and backward-filtered signals, so as to produce the estimates of the transmitted values. An accuracy of the estimates of the transmitted values is assessed, and coefficients of the forward filter are adapted depending on the assessed accuracy.

Abstract: An amplifier circuitry having adjustable parameters is presented. The present amplifier circuitry includes a feed-back loop, wherein the feedback loop converts (26) a signal to another frequency, filters (20) the signal in the other frequency, and restores (24) the filtered signal back to the original frequency for inputting the signal to an input of the amplifier (22). The feed-back loop implements a band-stop filter (20) having an adjustable stopband causing the amplifier circuitry to have an adjustable band-pass response. A passband of the amplifier circuitry is changed from one operating frequency to another operating frequency by changing frequency conversion parameters of the feedback loop.

Abstract: A wireless receiver comprises a band-pass filter module that includes an input for receiving a first pilot signal, an output that generates a first signal based on the first pilot signal, and a control input for adjusting a center frequency of the band-pass filter module. A control module determines the energy of the first signal, generates a control signal based on the energy, and communicates the control signal to the control input of the band-pass filter module.

Abstract: A network device includes a physical layer transceiver configured to receive incoming data on a data link at an input clock rate and to store the incoming data in a buffer. The physical layer transceiver includes a Media Independent Interface (MII) controller configured to receive the incoming data stored in the buffer and to transmit the incoming data over a MII bus based on a MII clock where the MII clock is a spread spectrum clock. The network device further includes a Media Access Control (MAC) device configured to receiving incoming data from the physical layer transceiver over the MII bus where the incoming data is clocked by the spread spectrum MII clock.

Abstract: A portable computing device includes an FEM, a SAW-less receiver, a SAW-less transmitter, and a baseband processing unit. The FEM isolates one or more outbound RF signals from one or more inbound RF signals. The SAW-less receiver converts the one or more inbound RF signals into one or more inbound intermediate frequency (IF) signals by frequency translating a baseband filter response to an IF filter response and/or an RF filter response. The SAW-less receiver filters the inbound RF signal(s) in accordance with the RF filter response and/or filters the inbound IF signal(s) in accordance with the IF filter response. The SAW-less receiver then converts the inbound IF signal(s) into inbound symbol stream(s). The SAW-less transmitter converts outbound symbol stream(s) into the outbound RF signal(s). The baseband processing unit converts outbound data into the outbound symbol stream(s) and convert the inbound symbol stream(s) into inbound data.

Abstract: A receiver includes an antenna interface, a frequency translation bandpass filter (FTBPF), a sample and hold module, and a down conversion module. The antenna interface is operable to receive a received wireless signal from an antenna structure and to isolate the received wireless signal from another wireless signal. The FTBPF is operable to filter the received wireless signal to produce an inbound wireless signal. The sample and hold module is operable to sample and hold the inbound wireless signal in accordance with an S&H clock signal to produce a frequency domain sample pulse train. The down conversion module is operable to convert the frequency domain sample pulse train into an inbound baseband signal.

Abstract: An RF signal reception device including: a transposition device of signals of frequency fRF to a first intermediate frequency IF1<fRF; a first bandpass filter centered on IF1; a sampler at a frequency fs<IF1; a second discrete-time filter centered on a second intermediate frequency IF2=?·fs/M+fs/(M·n); a decimation device of a factor M; an analog-digital convertor to operate at a frequency fs/M; where ?, n and M are strictly positive real numbers chosen such that: ?<fs/(2·BWch·M), and BWch/2<fs/M·n), with BWch: bandwidth of a channel of the received RF signals.

Abstract: One embodiment of the present invention provides a receiver for wireless communication. The receiver includes a demodulator and at least one filtering mechanism coupled to the demodulator, and an analog-to-digital converter (ADC) coupled to the filtering mechanism. The filtering mechanism can be configured to function as a low-pass filter (LPF) or a band-pass filter (BPF), thereby enabling the receiver to function as a direct-conversion receiver or a low-intermediate frequency (low-IF) receiver.

Abstract: A receiver includes an input section, a plurality of RF sections, an output circuit, and a controller. The input section receives and amplifies a radio frequency (RF) input signal to provide an amplified RF signal, and has a gain input. The plurality of RF sections each have an input for receiving the amplified RF signal, and an output for providing an intermediate frequency signal. The output circuit provides an intermediate frequency output signal in response to an output of at least one of the plurality of RF sections. The controller has an output coupled to the gain input of the input section.

Abstract: A receiving apparatus is provided. The receiving apparatus comprises a chip carrier including at least one stack of layers, wherein at least one layer in the stack supports radio frequency transmission lines, tunable bandpass filters, wherein each bandpass filter is integrated within an associated radio frequency transmission line, and at least one integrated micro-chip on the chip carrier. The at least one integrated micro-chip couples selected bandwidth regions of received broadband radio frequency signals to the tunable bandpass filters via the associated radio frequency transmission line. The at least one integrated micro-chip outputs each filtered selected bandwidth region to an associated one of a plurality of intermediate frequency modules.

Abstract: The present disclosure relates to a multi-band RF power amplifier (PA) module, which is used to receive, filter, and amplify a first RF input signal to provide a first RF output signal using a first tunable bandpass and notch filter. The multi-band RF PA module may include a supporting substrate having at least a first inductive element that provides a first portion of the first tunable bandpass and notch filter. Further, the multi-band RF PA module may include at least a first semiconductor die, which is attached to the supporting substrate and provides a second portion of the first tunable bandpass and notch filter. A transceiver module may provide the first RF input signal.

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 multimode communication device with a shared signal path programmable filter and a method for utilizing a shared signal path programmable filter in a multimode communication device. Various aspects of the present invention comprise a first module adapted to receive a first communication signal (e.g., corresponding to a first communication protocol) and a second module adapted to receive a second communication signal (e.g., corresponding to a second communication protocol). A shared filter, communicatively coupled to the first and second modules, may be adapted to filter the first and/or second communication signals in accordance with a plurality of selectable sets of filter response characteristics (e.g., associated with the first and second communication protocols). A filter control module may be adapted to select a set of filter response characteristics from a plurality of such sets and program the shared filter to filter a communication signal in accordance with the selected set.

Abstract: A demodulator of an FM signal modulated about a carrier frequency with a modulation frequency has an RF oscillator configured to be synchronized, under identical conditions of operation, with oscillations at first and second frequencies used in the FM signal to encode respective pieces of information. The oscillator has a magnetoresistive device; and a low-pass filter connected to an output electrode of the magnetoresistive device to filter an oscillating signal, generated by the oscillator and to a rendering terminal to provide, as a demodulated electrical signal, the filtered signal, the cut-off frequency fc at ?3 dB of this filter being strictly lower than the frequency and higher than the modulation frequency.

Abstract: A balance filter packaging chip having a balun mounted therein and a manufacturing method thereof are provided. The balance filter packaging chip includes a device substrate; a balance filter mounted on the device substrate; a bonding layer stacked on a certain area of the device substrate; a packaging substrate having a cavity formed over the balance filter, and combined with the device substrate by the bonding layer; a balun located on a certain area over the packaging substrate; and an insulator layer for passivating the balun. Accordingly, the present invention can reduce an element size and simplify a manufacturing process.

Abstract: A filter includes a first port, a second port, a first fractal curve based filter element coupled to the first port, and a second fractal curve based filter element coupled to the second port. The first fractal curve based filter element has first electromagnetic properties and the second fractal curve based filter element has second electromagnetic properties. The first fractal curve based filter element is electromagnetically coupled to the second fractal curve based filter element to filter radio frequency (RF) signals.

Abstract: A radio receiver circuit configured to receive a radio frequency signal and produce a baseband signal as an output therefrom has a channel filter having a bandwidth, the channel filter configured to receive the baseband output at a filter input and produce a filtered output at a filter output thereof. A signal-to-noise ratio (SNR) estimator prior to or after the channel filter or both is configured to estimate a signal-to-noise ratio of the baseband signal. A filter controller is configured to receive the signal-to-noise ratio estimate and control the channel filter to adjust the bandwidth thereof in accord with the signal-to-noise ratio estimate. This process thereby assists in improving SNR after the channel filtering by varying the channel filter bandwidth. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: Capacitive circuits are implemented with desirable quality factors in various implementations. According to an example embodiment, a fringe capacitor includes two capacitive circuits (e.g., plates), respectively having a plurality of capacitive fingers extending from an end structure, and respectively having a connecting pin that is adjacent the connecting pin of the other capacitive circuit, on a common side fringe capacitor. The capacitive fingers are arranged in stacked layers, with vias connecting the fingers in different layers back to the connecting pins.

Abstract: The present invention receives simultaneously RF signal of different frequency band and processes the RF signal received, at this time a BPS receiver minimizes aliasing generated by RF signal. The present invention comprises a sampling process unit which samples a signal summing a first RF signal and a second RF signal of different frequency bands with time gap, a quantization process unit which generates a first stream signal and a second stream signal from signals sampled by the sampling process unit according respective time information in the signal summing the first RF signal and the second RF signal and a signal process unit which performs FIR filtering with reference to phase shift for a respect frequency band of the first stream signal and the second stream signal, separates the first RF signal and the second RF signal based on a result of the performance.

Abstract: This invention concerns a repeater for radio frequency signals having a channel filter and an active filter connected to the channel filter output. The active filter covers the channels adjacent to the channel filter and includes an amplifier and; two bandpass filters in parallel connected as a negative feedback loop around the amplifier. The first bandpass filter covers the lower adjacent channels and the second bandpass filter covers the higher adjacent channels. The invention notably applies to the development of domestic repeaters for mobile terminals meeting the DVB-H digital television standard.

Abstract: A SAW-less receiver includes an FEM interface module, an RF to IF receiver section, and a receiver IF to baseband section. The RF to IF receiver section includes a mixing module, a mixed buffer section, and a frequency translated BPF (FTBPF) circuit module. The mixing module converts an inbound RF signal into an in-phase (I) mixed signal and a quadrature (Q) mixed signal. The mixed buffer section filters and buffers the I mixed signal and filter and buffer the Q mixed signal. The FTBPF circuit module frequency translates a baseband filter response to an IF filter response such that the FTBPF circuit module filters undesired signal components of the IF I signal and the IF Q signal to produce an inbound IF signal. The receiver IF to baseband section converts the inbound IF signal into one or more inbound symbol streams.

Abstract: A system for detecting and minimizing interference in a radio receiver includes a plurality of bandpass filters having different response characteristics, a power detector configured to compare a power output of a first bandpass filter and a second bandpass filter, and logic to cascade a third bandpass filter when the difference in power output between the power output of the first bandpass filter and the power output of the second bandpass filter exceeds a threshold amount.

Abstract: An access node receives a device beacon transmitted from a wireless communication device in accordance with a system timing of a wireless wide area network (WWAN). When transmitted within a WWAN uplink channel, the device beacon is mapped to designated beacon channels within the time-frequency space of the uplink WWAN channel assignment. In response to the reception of the device beacon, communications between the wireless communication device and the access node are established. In one example, the access node is a femtocell base station. In another example, the access node is a wireless local area network (WLAN) access point.

Abstract: A method for tuning a filter is provided. The amplitude of a first signal (I1) is compared with the amplitude of a comparison signal. The first signal is generated with a first filter, which receives a first input signal, and there is a phase difference between the first signal (I1) and the comparison signal. A tuning signal is then generated based on differences between the amplitudes of the first signal (I1) and the comparison signal. The tuning signal compensates for any phase and/or amplitude offset in the first signal (I1).

Abstract: Gain setting can be performed at high speed while reducing DC offset due to a filter cutoff frequency changeover without the need for input signal muting. A filter circuit having first and second filters is capable of allowing settings of first and second cutoff frequencies. First and second filter switch circuits and a charging circuit including a charging resistor and a charging switch are provided. For a first time period, the first switch circuit is controllably turned on while the second switch circuit is controllably turned off, thereby providing the first filter function. For a second time period, the first switch circuit is controllably turned off while the second switch circuit is controllably turned on, thereby providing the second filter function. For the first time period, the charging switch is controllably turned on so that the second capacitor is charged via the charging resistor.

Abstract: A half-bandwidth based quadrature analog-to-digital converter (ADC) includes in-phase circuitry, quadrature-phase circuitry, and digital complex processing circuitry. The in-phase circuitry includes an in-phase pair of ADCs, which provide an in-phase pair of sub-quadrature output signals, based on an analog in-phase input signal. Similarly, the quadrature-phase circuitry includes a quadrature-phase pair of ADCs, which provide a quadrature-phase pair of sub-quadrature output signals based on an analog quadrature-phase input signal. The digital complex processing circuitry combines, filters, and restructures the in-phase pair of sub-quadrature output signals and the quadrature-phase pair of sub-quadrature output signals to provide a digital in-phase output signal and a digital quadrature-phase output signal. Each of the in-phase pair of ADCs has about an ADC bandwidth. The in-phase circuitry has an input bandwidth, which is about equal to two times the ADC bandwidth in one embodiment of the in-phase circuitry.

Abstract: Receiving an indication of a frequency ratio of first and second clocks; generating an indication of a number of clock pulses of the second clock occurring between first and second clock pulses of the first clock; and generating an indication of a time offset between (1) a clock pulse of the second clock occurring between the second clock pulse and a third clock pulse of the first clock, and (2) the second clock pulse of the first clock. Also, receiving an input data word representing a fractional number, a first part of the input data word comprising an integer portion of the fractional number and a second part comprising a decimal portion of the fractional number; providing a first output data word that is either the first part of the input data word or an increment by one of the first part; and providing a second output data word that is an integer multiple of the second part.

Abstract: The following embodiments relate to an analog filter having an adjustable transfer function for use in a system or circuit that processes a signal having a changing data rate. The transfer function may be adjusted by adjusting the resistance and/or capacitance of components of the analog filter. The analog filter is calibrated based on an optimum operational parameter at a certain data rate, such as a median data rate. The analog filter may be further adjusted as the data rate of the signal changes.

Abstract: An integrated wideband receiver includes first and second signal processing paths and a controller. The first signal processing path has an input, and an output for providing a first processed signal, and comprises a first tracking bandpass filter having a first integrated inductor. The second signal processing path has an input, and an output for providing a second processed signal, and comprises a second tracking bandpass filter having a second integrated inductor. The controller is for enabling one of the first and second signal processing paths corresponding to a selected channel of a radio frequency (RF) input signal to provide an output signal. The controller, the first integrated inductor, and said second integrated inductor are formed on a single integrated circuit chip.

Abstract: Present software-defined radios (SDR) employ front end circuits that contain multiple receivers and transmitters for each band of interest, which is inflexible, expensive and power inefficient. A programmable front end circuit is implemented on a CMOS device and is configurable to transmit and receive signals in a wide band of frequencies, thereby providing an adaptable transmitter and receiver operable with current and future wireless networking technologies.

Abstract: Disclosed herein are systems and methods for recovering a sub-carrier signal from a multiplexed signal having an embedded pilot tone signal. The recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for generating a frequency-doubled signal from the recovered pilot signal, and for phase-shifting the frequency-doubled signal by a pre-determined phase difference from the embedded pilot tone signal. Another recovery system includes circuitry for recovering a pilot signal from the received multiplexed signal, for phase-shifting the pilot signal by a pre-determined phase difference from the embedded pilot tone signal, and for generating a frequency-doubled signal from the phase-shifted signal.

Abstract: Embodiments of a SAW-less RF receiver front-end that includes a frequency translated notch filter (FTNF) are presented. An FTNF includes a passive mixer and a baseband impedance. The baseband impedance includes capacitors that form a low-Q band-stop filter. The passive mixer is configured to translate the baseband impedance to a higher frequency. The translated baseband impedance forms a high-Q notch filter and is presented at the input of the FTNF. The FTNF can be fully integrated in CMOS IC technology (or others, e.g., Bipolar, BiCMOS, and SiGe) and applied in wireless receiver systems including EDGE/GSM, Wideband Code Division Multiple Access (WCDMA), Bluetooth, and wireless LANs (e.g., IEEE 802.11). In addition, embodiments of a generalized FTNF for wideband applications are presented.

Abstract: In a receiver, a synchronization circuit (MIX2, C1, R1, VCO) provides a set of oscillator signals (OSI, OSQ, OSX, OSY) that are synchronized with a carrier of an amplitude-modulated signal. The set of oscillator signals (OSI, OSQ, OSX, OSY) comprises a first amplitude-demodulation oscillator signal (OSX) and a second amplitude-demodulation oscillator signal (OSY) that differ in phase. A first amplitude-demodulation mixer (MIX3) mixes the first amplitude-demodulation oscillator signal (OSX) with the amplitude-modulated signal so as to obtain a first amplitude-demodulated signal (MO3). A second amplitude-demodulation mixer (MIX4) mixes the second amplitude-demodulation oscillator signal (OSY) with the amplitude-modulated signal so as to obtain a second amplitude-demodulated signal (MO4). A magnitude comparator (MDT1, MDT2, DDT) compares respective magnitudes (M+, M?) of the first amplitude-demodulated signal (MO3) and the second amplitude-demodulated signal.

Abstract: There is provided a communication device including: a high frequency coupler; a band-pass filter; a switching mechanism that switches an electrical length a transmission line between the high frequency coupler and the band-pass filter; a communication unit that receives hardware information of other end of communication before establishing a communication connection; and a control unit that controls switching of the electrical length of the transmission line according to the received hardware information of the other end of communication by using the switching mechanism with or after establishing a communication connection.

Abstract: Techniques for a receiver includes a low noise amplifier, a Q-enhanced bandpass filter on a chip, and an analog to digital converter (ADC) at a sub-sampling speed suitable for an intermediate frequency (IF) signal. In some embodiments, a temperature compensation circuit is included. The receiver has an effective noise level less than 7 dB. In some embodiments a 1-bit ADC is used. In some of these embodiments, one or more switches in the ADC are inverted to cancel charge injection.

Abstract: An improved variable matching network for use in a multi-band, multi-mode communications device provides dynamic, fine-tune impedance matching based on current operational conditions associated with a given signal. In one embodiment, gross parameters are selected based on one or more of the operational conditions. Delta parameters are provided using an optimization algorithm based on one or more of the operational conditions. And the gross and delta parameters are combined to obtain overall matching parameters that dynamically fine-tune discrete matching circuitry.

Abstract: An agile RF tuner circuit capable of converting a wide portion of RF signal into an IF signal suitable for analog-to-digital conversion. The circuit up converts a received RF signal to a high IF signal and then down converts the high IF signal to a low IF signal. Embodiments of the RF circuit incorporate harmonic reject mixers to suppress harmonics and intermodulations typically associated with the frequency conversion process.

Abstract: An apparatus and method for demodulating an FM RF signal is presented. An Adaptive Differentiate Cross Multiply (ADCM) system in which the energy estimate of the desired on-channel RF is generated using adaptive filtering. The adaptive filter includes low pass filtering of the instantaneous energy estimate. The bandwidth of the LPF is adjusted in real time based on the received signal strength energy estimate, the periodicity of any changes in the energy estimate, AGC setting for the receiver, and/or the type of sub-audible signaling applied to the RF signal if known. After the bandwidth is set, the optimum filtered energy estimate is applied to the system to demodulate the received information free from distortion artifacts associated with IQ imbalance. A normalized signal in the ADCM system is clipped by a limiter whose clipping threshold is equal to a maximum gain of differentiators in the ADCM system.

Abstract: A receiver includes an input to receive data of a pilot channel having a carrier frequency associated therewith, and a first unit to obtain a quantity, wherein the quantity depends on a frequency broadening of the received data and a frequency shift of the received data with respect to the carrier frequency. The receiver also includes a second unit to adjust the bandwidth of a channel estimation unit, wherein the adjustment depends on the quantity.