Abstract: A method and system for compensating for frequency dependent phase and amplitude imbalances is provided. A plurality of frequency sub-bands is extracted from a received wideband signal. Each of the plurality of frequency sub-bands is compensated to produce an associated plurality of compensated frequency sub-bands. The compensated sub-bands are summed in order to produce a compensated signal.

Abstract: This technique relates to a receiving device, a receiving method, and a program that can demodulate transmitted signals with high accuracy. A receiving device of this disclosure includes: an amplifying unit that amplifies a received signal; an adjusting unit that adjusts gain of the amplifying unit in accordance with power of the signal; a demodulating unit that demodulates the amplified signal; and a detecting unit that detects an interval from the signal, information having the same content continuously appearing in the interval. The adjusting unit restricts the process of adjusting the gain of the amplifying unit in accordance with a result of the detection of the interval. This disclosure can be applied to receiving devices that receive broadcast signals compliant with DVB-C2 via a CATV network.

Abstract: A high temperature communications circuit includes a power conductor for concurrently conducting electrical energy for powering circuit components and transmitting a modulated data signal, and a demodulator for demodulating the data signal and generating a serial bit stream based on the data signal. The demodulator includes an absolute value amplifier for conditionally inverting or conditionally passing a signal applied to the absolute value amplifier. The absolute value amplifier utilizes no diodes to control the conditional inversion or passing of the signal applied to the absolute value amplifier.

Abstract: A monitoring apparatus includes a detection circuit, a filter circuit, an amplifying circuit, a regulation circuit, a delay and charging circuit, and a driving circuit. The detection circuit receives a video signal, and performs an operation to obtain an image signal from the video signal. The filter circuit obtains an average intensity of a luminance signal corresponding to the image signal. The delay and charging circuit charges an input capacitor when receiving a low level regulated signal from the amplifying circuit. The driving circuit activates an alarm when a charging voltage of the chargeable capacitor exceeds a predetermined value.

Abstract: The present invention provides a universal demodulation circuit, a load modulation circuit and associated method, and an associated power transfer system, all suitable for use in wireless power transfer. A power receiver with signal strength detection is also provided. Modulation of the impedance of the demodulation circuit is determinable by detecting the amplitudes of a first and a second electrical parameter, thereby demodulating data communicated by modulation of the impedance of the demodulation circuit. The modulation circuit has a communication modulator to modulate the impedance of the modulation circuit, to a predetermined minimum modulation depth, thereby to communicate data.

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: In one embodiment, a method for processing radio frequency signals includes estimating an average value of a demodulated signal and a noise signal, both obtained from a radio frequency signal, estimating a noise floor based on the noise signal, generating a blend control signal based on the average values and the noise floor, and blending at least two path signals based on the blend control signal to obtain a blended signal. This blended signal may be output for further processing when multipath noise is detected.

Abstract: A method for demodulating an RF input signal using an envelope detector and synchronous switching of the input signal before entering and after leaving the envelope detector, the envelope detector having a non-linear transfer function acting essentially as a squaring function. The invention also relates to an electronic receiver circuit performing such a method, and to an RF receiver comprising such an electronic receiver, and to an electronic device comprising such an RF receiver, and to the use of such an RF receiver as a wake-up receiver.

Abstract: The present invention provides a universal demodulation circuit, a load modulation circuit and associated method, and an associated power transfer system, all suitable for use in wireless power transfer. A power receiver with signal strength detection is also provided. Modulation of the impedance of the demodulation circuit is determinable by detecting the amplitudes of a first and a second electrical parameter, thereby demodulating data communicated by modulation of the impedance of the demodulation circuit. The modulation circuit has a communication modulator to modulate the impedance of the modulation circuit, to a predetermined minimum modulation depth, thereby to communicate data.

Abstract: A receiver estimates I/Q imbalance in I and Q input signals using circuitry to separate different frequency components of the I and Q input signals, and estimation circuitry arranged to estimate I/Q imbalance at the different frequency bands. The separating of the bands may be carried out in the frequency domain, and may involve combining corresponding values representing corresponding negative and positive frequency bands, and converting the separated frequency domain representations to a time domain representation before the estimation. The estimated imbalance may be used to correct the I and Q signals at the different frequency bands.

Abstract: The device and method of the present invention improves electronic communication which have behavioral consequences, including for example, flight communication, two-way closed circuit communication such as for fire, police, miners, scuba divers and other heath and safety workers, and even for mobile communication which happens during activities such as cellular or mobile conversations during driving. Dichotic listening techniques are altered to enhance dyadic (involving two people) interactions with a partner. The speech of at least the first member of the dyad is filtered to isolate the component below 0.5 Khz, which will be input with a gain to the left ear of the second person (provided that they are right-handed), and thus their right cerebral hemispheres, and the component with a frequency above 0.5 Khz. will be input to their right ears, and thus their left cerebral hemispheres.

Abstract: The present invention provides a low intermediate frequency receiver for receiving radio frequency signal and provides the sampling method thereof. The low intermediate frequency receiver firstly samples the radio frequency signal so as to convert it into digital signal of non-zero frequency domain. Secondly it compensates the digital signal of non-zero frequency domain to filter out the interfering signal therein. Finally, the compensated digital signal is frequency-shifted to the zero frequency domain. By using the low intermediate frequency receiver and the sampling method thereof according to the present invention, the interference at the zero frequency, like DC drift and intermodulation component, could be easily filtered out without imposing any great influence on the useful signals.

Abstract: A radio receiver (FM radio receiver) has an amplitude detecting section (13) for detecting the amplitude level of a received radio wave; a multipath occurrence state detecting section (14) for monitoring the amplitude level, and for detecting the degree of a multipath occurrence state; a multipath occurrence state deciding section (15) for deciding the operation limiting level of the amplitude correction according to the degree of the multipath occurrence state; a receiving condition deciding section (20) for deciding receiving conditions of the radio wave; and a limiting level deciding section (21) for adjusting the operation limiting level of the amplitude correction output from the multipath occurrence state deciding section (15) according to a receiving condition decision result output from the receiving condition deciding section (20), and suppresses the multipath noise by imposing operation limitations on the amplitude correction of the FM demodulator 9.

Abstract: A radio terminal unit and a radio communication system, enabling power savings, the improvement of the quality of real-time communication such as voice communication, and the reduction of transmission delays which often occur when a plurality of radio terminal units are connected to one radio base station. A radio terminal unit comprises a communication control section for controlling a radio interface section to transmit a control packet using a timer value.

Abstract: A wireless communication device comprises a number of sub-systems operably coupled to a data interface for routeing data between the number of sub-systems. A clock generation function generates a clock signal substantially at a data transfer rate to be used over the data interface whereby the clock signal is generated at a rate that minimises harmonic content of the clock signal at operational frequencies of the wireless communication device. Thus, a suitable data rate is selected and supported by the data interface that accommodates the desired bandwidth, clock rate and/or chip rate of the functional elements that are coupled by the data interface within the wireless communication device, whilst minimising the effects of harmonic interference from the clock signal(s).

Abstract: Methods, apparatus, and articles of manufacture are disclosed for removing an undesired component from a low intermediate frequency signal having an intermediate center frequency and an undesired component at a first frequency. One example method may include determining an amplitude of the undesired component; frequency shifting the low intermediate frequency signal from the intermediate center frequency to produce a zero intermediate frequency signal; filtering the zero intermediate frequency signal; generating a tone based on the amplitude of the undesired component; and subtracting the tone from the filtered zero intermediate frequency signal to remove the undesired component.

Abstract: A wireless receiver which is used for a digital signal transmission system to wirelessly transmit a digital signal by packetizing and modifying it, selectively sets the shortest arithmetical bit length satisfying a required communication quality when performs demodulation arithmetical processing to demodulate a digital signal to be packet-transmitted, inputs a demodulation arithmetical result by the arithmetical bit length to calculate an error vector magnitude value that is a measure indicating a difference between the arithmetical result and a known ideal result, predicts a bit error rate by using the EVM value as an evaluation criterion, selects an arithmetical bit length by which the bit error rate becomes optimum, and executes the demodulating arithmetical processing by the selected arithmetical bit length.

Abstract: In one aspect, the present invention includes an automatic volume control (AVC) circuit to receive a demodulated signal and provide an output signal at a substantially constant volume. The circuit may be implemented in hardware, software, and/or firmware to perform digital demodulation, programmable amplification, and high pass filtering to provide a substantially constant volume output.

Abstract: Aspects of the method and system for rejecting single sided leakage into an amplitude modulated channel may comprise an AM demodulator for demodulating a received composite broadcast signal's control channel to generate an amplitude modulated (AM) component. A PM demodulator may demodulate a received composite broadcast signal's control channel to generate a phase modulated (PM) component. At least one subtractor may subtract an AM leakage component and a PM leakage component contributed by the single sided leakage in the received composite broadcast signal's control channel. The system may comprise at least one of each of AM and PM bandpass filters and envelope detectors that filter and detect envelopes of the AM and PM components at 982.5 Hz and 922.5 Hz.

Abstract: Embodiments of the present invention include circuits and methods for reducing DC Offset. In one embodiment the present invention includes storing DC offset on internal capacitances. In one embodiment, parallel stages are used to remove DC offset corresponding to different local oscillator frequencies. Embodiments of the invention further include changing the low cutoff frequency of the DC cancellation circuits for fast calibration. In a first state, a high pass filter may have a first low cutoff frequency, and in a second state the high pass filter may have a second cutoff frequency lower than the first low cutoff frequency. The present invention also includes a variable gain amplifier with reduced DC offset.

Abstract: Disclosed is a mobile communication terminal which is provided with an equalizer function of audio equipment to adjust a timbre of transmitting/received speech sounds so as to satisfy a great number of users having various individualities and tastes simultaneously. The mobile communication terminal according to the present invention includes an equalizer connected to a CODEC, a speaker and a microphone for adjusting a timbre of an analog speech signal inputted thereto from the CODEC and/or a speech signal inputted thereto through the microphone, and an equalizer control circuit for controlling a timbre control operation of the equalizer according to a control signal of a CPU.

Abstract: Frequency offset estimation apparatus for estimating the offset from a predetermined centre frequency of an input signal carrying a plurality of frequency shifted symbols, the apparatus comprising: a demodulator for demodulating the input signal to estimate the symbols; a first filter for forming a first estimate of the offset by determining the average of a first predetermined number of the last maxima and minima of the instantaneous frequency difference between the input signal and a signal at the centre frequency; a second filter for forming a second estimate of the offset by determining the average of the values of the instantaneous frequency difference between the input signal at the centre frequency associated with the estimation by the demodulator of those of the symbols having the greatest positive and negative frequency shifts; and selector for selecting the first estimate or the second estimate as an output estimate of the frequency error.

Abstract: A communication apparatus includes a mechanism for preventing demodulation of text telephone information during reception of a poor quality signal. In one embodiment, the communication apparatus includes a receiver including a demodulator unit configured to receive a signal including a plurality of text telephone symbols. The demodulator unit may be configured to generate a soft decision based upon a frequency and an energy value of each received text telephone symbol. The demodulator unit may be configured to receive a notification that indicates the signal is unusable. In response to receiving the notification, the demodulator unit may be further configured to generate predetermined information that is independent of the plurality of text telephone symbols.

Abstract: An inexpensive, high-performance, fully-integrable, multi-standard transceiver with a topology including: an active mixer, followed by a high pass filter, and a passive mixer. The input signal is modulated up, or demodulated down, using a pair of complementary, aperiodic mixing signals. The use of aperiodic mixing signals allows a fully-integrated transceiver to be built. Embodiments of the active mixer include those having electrically-adjustable performance and allowing multiple RF signal inputs. This allows the topology to be employed in multi-band, multi-frequency applications, while still providing high performance.

Abstract: Systems and methods for passively calibrating and correcting for I/Q mismatch in a quadrature receiver without the necessity of modifying the analog portion of the receiver by adding calibration signals or correction circuitry are presented. The passive I/Q mismatch calibration system proceeds using normally received incoming transmitted data signals to obtain statistical information on which to base I/Q mismatch compensation factors. The I/Q mismatch compensation factors can be used to adjust the magnitude and phase response in the time domain or the frequency domain, the analog or the digital portion of the receiver. Depending on the embodiment, the passive I/Q mismatch calibration system can calibrate frequency dependent gain or magnitude imbalance, frequency independent magnitude imbalance, frequency dependent phase imbalance, and frequency independent phase imbalance or combinations or these.

Abstract: The present invention is to provide a microwave filter distributed on a circuit board of a wireless communication product, which comprises an input terminal, a resonant chamber of double frequencies, and an output terminal of the microwave filter directly distributed on the circuit board of the wireless communication product as a plurality of microstrips by utilizing a manufacturing technique of printed circuit board for eliminating the harmonic spurious of double frequencies and higher frequency caused by nonlinear distortion of a power amplifier of the wireless communication product.

Abstract: The present invention provides a multimode receiver design for mitigation of frequency offset by selective demodulation of an input modulated signal. The receiver (103) comprises a plurality of demodulators (207). Each of the plurality of demodulators (207) has the same functionality but different receiver sensitivity versus frequency-offset mitigation characteristics. Each of these demodulators incorporates a different demodulation technique. A suitable demodulator is selected to demodulate the received signal. The choice of a suitable demodulator is based on the value of the frequency offset (305, 307).

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: A wireless user terminal (42) and system (40) implementing a mixed signal CODEC (100) including an improved sigma-delta ADC (18) which limits input signals into a switched capacitor configuration and avoids adding circuit overhead in the signal path is disclosed herein. This sigma-delta analog-to-digital converter (18), having an input signal and an output signal, includes a switch (sw1), a clipping circuit (20), and a known sigma-delta ADC (34). It solves the clipping signal problem by limiting the signal right at the input of the sigma-delta ADC (34). The clipping circuit (20) couples to the switch (sw1) and the sigma-delta ADC (34) for switching the voltage applied to the sigma-delta ADC between the input signal (vin) and at least one threshold voltage (Vn and Vp).

Abstract: A multipath noise reducer extracts a high-frequency signal from a demodulated signal obtained from a frequency-modulated signal, and generates a noise reduction coefficient from the extracted high-frequency signal. The demodulated signal is also separated into high-frequency and low-frequency components, the high-frequency component is multiplied by the noise reduction coefficient, and the resulting product is added to the low-frequency component. An output signal is thereby obtained in which the spike noise that characterizes multipath reception of a frequency-modulated signal is reduced with relatively little distortion of other parts of the signal, including the parts between noise spikes. The distortion can be further reduced by replacing the demodulated signal with an interpolated signal during noise spikes before the low-frequency component is separated.

Abstract: A baseband analog circuit includes a demodulator to demodulate a received signal and to output a baseband analog signal, a low-pass filter to filter the demodulated baseband analog signal, and an impedance converter, provided between the demodulator and the low-pass filter, having lower output impedance than the output impedance of the demodulator.

Abstract: The invention relates to a method of demodulating a signal (I, Q) that has a main component and harmonics. According to the invetion, this method includes the following of a selection of one of the harmonics, and a demodulation of the selected harmonic. The invention enables the elimination of a parasitic component introduced by the demodulation into the demodulated signal SD without altering the data carried by the signal SD.

Abstract: In a method of avoiding a band interference wave which is produced in a receiver when a reception frequency used for radio communication is converted into a fixed intermediate frequency by using the oscillation frequency of a local signal oscillator, when the frequency of a reception signal is on the low-frequency side in a reception frequency band, channel setting and route switching control are so performed as to make the reception signal pass through a low-pass filter. A circuit for avoiding a band interference wave is also disclosed.

Abstract: The demodulator according to the invention comprises a negative feedback loop which slowly compensates for a DC potential of a demodulated signal through an integrator formed of a resistor and a capacitor, and a negative feedback loop which senses a amplitude of a demodulated signal and rapidly charges or discharge the capacitor in response to the result of the sensing, wherein the two negative feedback loop operate independently of each other.

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: This invention provides an FM demodulating device for robustly demodulating a received FM signal even under a jammed communication condition through the use of an improved extended Kalman filtering scheme, which is applied to the FM communication system exhibiting a random occurrence of cochannel.

Abstract: In a radio pager capable of receiving a paging signal subjected to multilevel digital frequency modulation, an analog-to-digital converter (ADC) receives a demodulated voltage signal in the form of an analog signal from a demodulator. The ADC functions to define the upper limit of an analog signal conversion range with a first reference voltage and to define the lower limit of the same with a second reference voltage. Even when at least one of the demodulation sensitivity and demodulated center voltage of the demodulated voltage signal changes with a change in temperature and causes the signal to change, the relation between the signal range of the demodulated voltage signal and the analog signal conversion range of the ADC is maintained constant. Therefore, even if the demodulated voltage signal before temperature compensation changes, the ADC is capable of outputting a stable digital signal identical in content or data with an intermediate frequency signal input to the demodulator.

Abstract: An adaptive noise canceling system for improving a S/N ratio and clarity of a output signal includes a delay for delaying the input signal X(j) by a fixed time delay a, a filter for filtering the delayed signal D(j), a subtracter for subtracting the filtered signal Y(j) from the input signal X(j), a coefficients adjuster for adaptively adjusting coefficients of the filter using a least-means-square (LMS) algorithm, a level adjuster for adjusting a level of an error signal .epsilon.(j) which is obtained by subtracting the filtered signal Y(j) from the input signal X(j), and an adder for adding the level adjusted signal .epsilon.(j) to the filtered signal Y(j).

Abstract: In a digital FM receiver having a demodulator that receives a radio signal and generates therefrom a phase sample whose behavior determines an output of the demodulator, an apparatus for removing a low-frequency interference signal from the phase sample converts the phase sample into a frequency sample which is then high-pass filtered to produce a filtered frequency sample. The filtered frequency sample is then converted into a filtered phase sample, which may be further demodulated in accordance with known techniques. Converting the phase sample into a frequency sample may be performed by a first order difference circuit. Converting the filtered frequency sample into the filtered phase sample may be performed by an integrator.

Abstract: A method and apparatus for determining received signal strength of a radio frequency signal of a frequency dependent device to determine errors in automatic frequency control calculations. The method includes the steps of: 1 ) receiving the radio frequency signal; 2) providing at least two artificial thresholds based upon the signal during a first portion (45) of a signal block (32), wherein the artificial thresholds lie outside the peak and valley amplitudes of a demodulated intermediate signal (225) of the radio frequency signal; 3) providing automatic frequency control to determine a frequency error value (250) during a second portion (46) of the signal block (32); 4) determining a correction factor based upon the position of the demodulated signal in relation to the artificial thresholds during the second portion (46) of the signal block (32); and 5) varying the frequency of an adjustable crystal (220) in accordance with the correction factor applied to the frequency error value (250).

Abstract: In a receiver, a plurality of amplifiers each having a particular amplification factor amplifies a received signal. Analog-to-digital converters (ADCs) each converts the output of the respective amplifier to a digital value. The resulting digital values from the ADCs are written to respective memories. At the same time, maximum amplitude detectors respectively detect the maximum amplitudes of the associated digital values. A comparator locates, among the lines where the maximum amplitude of a burst does not reach either a positive saturation level or a negative saturation level, the line having a great amplification factor every time a burst appears. On receiving a control signal from the comparator, a selector transfers the digital value stored in the memory of the line selected to a signal processor. The signal processor demodulates and decodes the received signal based on the input digital value and delivers the output thereof to an output terminal.

Abstract: An FM demodulating circuit using a tracking filter is disclosed, in which the operation of the tracking filter following the frequency of the signal inputted therein is made more precise by using the tracking filter and an oscillator driven by a same control signal.

Abstract: A direct conversion receiver for demodulating an FM signal converted frequency down converts the signal to quadrature related baseband signals (I,Q). These signals are applied by way of respective d.c. blocking capacitors (16, 18) and differentiating circuits (26, 28) to a differential arctan demodulator (20). The action of the differentiating circuits (26, 28) is to remove any d.c. component in the I and Q signals and to perform a frequency shaping which enables the demodulator (20) to recover correctly the modulating information. Measures are disclosed to overcome the effects of 180 degree phase jumps which will occur when the direction of rotation of the phasor reverses and of frequency dependent amplitude scaling introduced into the differentiated signals (I', Q').

Abstract: A simplified carrier phase control apparatus used in a modem for demodulating a quadrature amplitude modulated data signal, to correct phase jitters of a carrier signal due to a 50 Hz or a 60 Hz frequency of the commercial power supply, and its harmonic wave frequency components. The carrier phase control apparatus has a predictive filter for predicting a carrier phase jitter, the predictive filter composed of band-pass filters with center frequencies of 50 Hz and 60 Hz, and a circuit where the output signals of the band-pass filters are multiplied by the coefficients and added linearly.

Abstract: A data limiter in a paging receiver for converting an analog signal to a digital signal, the data limiter having a variable time constant. The data limiter includes an amplifying circuit and an integrating circuit. The amplifying circuit, being responsive to the analog input signal generated from a receiving circuit of the paging receiver, generates a reference signal depending upon a variable bias current input to the amplifying circuit. The integrating circuit, being responsive to the reference signal, generates a comparison signal depending upon a variable gain input. The amplifying circuit responsive to the comparison signal compares the comparison signal to the input signal for generating a digital output signal. A processing circuit of the paging receiver generates a first control signal for modifying the variable bias current input and a second output signal for modifying the variable gain input.

Abstract: A microwave frequency discriminator, i.e. an electronic device for directly transforming frequency modulation on a microwave carrier into a demodulated lower frequency signal. The discriminator is similar to a Travis discriminator and includes an inlet microstrip line, two resonant circuits (R.sub.1, R.sub.2) constituted by dielectric resonators and coupled to said inlet microstrip line to receive the modulated microwave signal, two outlet microstrip lines coupling each resonator to a respective microwave detector circuit, said detector circuits including loads (r.sub.1, r.sub.2) in series-opposition in the manner of a Travis discriminator. The microwave frequency discriminator can be used in a demodulator and/or receiver for frequency modulated microwaves.

Abstract: A multipath noise detecting circuit, which is not affected by ignition noise nor by the level of the antenna input voltage, includes a band pass filter having a mean frequency of 114 KH supplied with signals output from a FM demodulator, an AM detector for subjecting the signal input from said band pass filter to AM-detection, and a detector section for detecting as multipath noise the pulses included in the signal output from said AM-detector.

Abstract: An apparatus for demodulating a frequency modulated input signal having a carrier signal component, including a filter for allowing only signals having frequency around the frequency of the carrier signal component and a demodulator connected to the filter for performing frequency demodulation, is provided with a noise eliminating circuit at a stage immediately before the filter. With this provision, an impulse noise having spectrum components of very wide band and which could not be rejected by the filter in prior art apparatuses, is eliminated before the demodulation.

Abstract: Multilevel baseband signals are applied to a full-wave rectifying section which produces first and second outputs. These outputs are applied to an analog-to-digital converting means which produces a plurality of recovered binary digital signals and an error signal. A controller is supplied with at least one recovered binary digital signal and the error signal, and produces two control signals which are fed to the full-wave rectifying section to compensate (a) first DC-drifts superimposed on the multilevel baseband signal and (b) second DC-drifts generated within the full-wave rectifying section itself.

Abstract: A communications receiver squelch circuit for use in frequency modulation systems which has tight squelch sensitivity. The squelch circuit includes two audio limiters and provides improved squelch sensitivity and squelch action that is independent of carrier modulation and significantly minimizes squelch clamping and squelch boost characteristics.