Abstract: A sub-threshold transistor bridge circuit for use in detecting the signal level of an input radio-frequency signal is disclosed. In an exemplary embodiment each branch of the sub-threshold transistor bridge circuit comprises a transistor configured to operate in the sub-threshold region over a predetermined range of input signal levels. An input radio-frequency signal applied to a first pair of opposing corners of the bridge circuit yields a bridge output signal at the remaining pair of opposing corners that has a low-frequency component substantially proportional to the squared-amplitude of the envelope of the input radio-frequency signal. Also disclosed are various detector circuits including a sub-threshold transistor bridge circuit, as well as methods for detecting a signal level for an radio-frequency signal using a sub-threshold transistor bridge.

Abstract: In a radio communication apparatus, a frequency offset calculator of the radio communication apparatus calculates a frequency offset of the received radio signal from the reception frequency of the radio communication apparatus. An averaging unit averages the frequency offset calculated by the frequency offset calculator. A moving speed calculator calculates the moving speed of an associated radio communication apparatus with which the radio communication apparatus is communicating, based on the frequency offset calculated by the frequency offset calculator. An averaging time changer changes an averaging time for which the frequency offset is averaged by the averaging unit, in accordance with the moving speed of the associated radio communication apparatus calculated by the moving speed calculator.

Abstract: Performing a decoding mode of a frequency modulation (FM) signal for an adaptive FM radio receiver includes passing the FM signal through a FM demodulator to obtain a composite signal that includes a pilot signal and noise around the pilot signal, passing the composite signal through a band bass filter, filtering the pilot signal from the noise using a pilot and noise separator that includes a notch filter that filters the pilot signal from the noise, obtaining average amplitudes of the pilot signal and the noise, comparing a ratio between the average amplitudes of the pilot signal and the noise with a programmable threshold, and selecting a decoding mode and an audio low pass filter. The decoding mode is selected based on a quality of the pilot signal being decoded and the audio LPF is selected based on the comparison ratio.

Abstract: A radio front end utilizes at least one band pass filter to pass only the appropriate frequency band. Once the desired frequency band has been isolated it is converted to a digital format in an analog to digital converter and a digital signal processing device interprets the signal.

Abstract: A device and a method for estimating a Carrier to Interference-plus-Noise Ratio (CINR) in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided. The CINR estimating method includes receiving a preamble symbol and transmitting subcarrier transmitted from a base station, calculating an interference power and noise power using the preamble symbol and transmitting subcarrier, calculating a receive power used for the base station to transmit a preamble and data symbol, estimating a preamble CINR value using an interference power, a noise power, and a receive power, calculating the noise power from a subcarrier not transmitting a preamble, and calculating an average CINR of data subcarriers using the preamble CINR value and the noise power. Accordingly, a precise CINR can be estimated using a preamble when the preamble power is amplified in comparison with the data symbol power.

Abstract: To detect phase mismatches between in-phase and quadrature signals of a quadrature demodulator. The phase mismatches can be detected using the signals obtained by removing high frequency components of output of a multiplier by a low pass filter, the output being the product of the in-phase signals of which low frequency components are removed by a first high pass filter by the quadrature signals of which low frequency components are removed by a second high pass filter.

Abstract: A near field detection device that detects a field near the body when appropriately connected to conductive plates. The near field is generated by an oscillatory voltage device which when in contact with the body permeates all that is in contact with the body. The detector electronics and conductive plates are packaged so that near contact with the body is accommodated. A footwear packaging scheme provides a convenient location to embed the detector invention, though other packaging arrangements and locations on the body are claimed. Auxiliary electronics may be included with the detector and conductive plates to provide additional synergistic functionality to the packaging scheme.

Abstract: An FM tuner that has a multipath reception detection unit and an adjacent-channel interference detection unit while reducing expansion of the scale of the circuit is available. A control signal for a stereo separation level is generated on the basis of a signal SM-DC corresponding to a reception field strength and of a signal SMP corresponding to a multipath noise component. The SMP is extracted from a fluctuation component signal SM-AC from an S-meter circuit 92 by a multipath noise extraction circuit 104. The multipath noise extraction circuit 104 used for control of the stereo separation level is shared as a portion of the circuitry for detecting the multipath signal reception state. A multipath reception detection unit 108 compares the SMP with a threshold value to detect a multipath reception state.

Abstract: MIMO detection is described that reduces the complexity of computations for finding the soft bit output. The detection process includes QR factorization splitting the distance calculations into two groups, subset lookup using a last cross constellation set (LCCS) lookup, and minimal distance lookup with soft bit output calculation. By grouping the distance calculations into a first group that has one antenna transmitting using a modulation scheme with a generally square constellation diagram and a second group for all of the other antenna constellation diagrams, the LCCS lookup process may be used which substantially reduces the number of calculations to be made in the detection process. Moreover, in the special case of 2×2 antenna, QR factorization is performed by applying a scaled Givens rotation to the channel matrix. The application of the scaled Givens rotation operator eliminates any square root operations that would be performed in a standard QR factorization.

Abstract: A frequency change detector splits a frequency standard signal into two undelayed frequency signals, one of which is delayed by a predetermined amount. The delayed signal is then mixed with the undelayed frequency signal into a mixed signal that is further filtered and amplified for providing an output signal indicating frequency changes of the frequency standard signal. The mixed frequency signal indicates frequency changes of the original frequency standard signal without reference to another frequency standard. This frequency change detector is well suited for use on satellites as an early warning detection of changes in on-board atomic frequency standards.

Abstract: A frequency converter (100) is provided, comprising: a pulse generator (150) configured to receive a balanced local oscillator signal pair and to generate a balanced rectangular pulse signal pair having the reference frequency; and a mixer (160) configured to mix an input signal having an input frequency with the balanced rectangular pulse signal pair to generate an output signal having an output frequency. The input frequency is different from the output frequency, and the pulse generator and the mixer are formed on a single integrated circuit (120). The frequency converter may comprise a balanced local oscillator (110) configured to generate the balanced local oscillator signal pair. The balanced local oscillator may comprise: an unbalanced local oscillator (130) configured to provide an unbalanced local oscillator signal having the reference frequency; and a balun (140) configured to generate the balanced local oscillator signal pair based on the unbalanced local oscillator signal.

Abstract: There is provided a method for use in a wireless communication to avoid detection of a false modulated signal in a paged device. In one embodiment, a modulated signal is received by the paged device. Then, the modulated signal is identified by the paged device as a preliminary false modulated signal. Thereafter, the gain of at least one paged device amplifier and/or a matching threshold of the paged device is reduced by the paged device to decrease a sensitivity of the paged device to avoid detection of a future false modulated signal. In one embodiment, the wireless communication is a Bluetooth wireless communication and the paged device is a Bluetooth enabled device. An exemplary system for implementing one embodiment of the disclosed method is described.

Abstract: A frequency synthesizer within an FM receiver employs a Phase-Locked Loop (PLL) to generate a Local Oscillator (LO) signal. The LO signal is supplied to a mixer. The FM receiver also includes jammer detection functionality. If no jammer is detected, then the loop bandwidth of the PLL is set to have a relatively high value, thereby favoring suppression of in-band residual FM. If a jammer is detected, then the loop bandwidth of the PLL is set to have a relatively low value, thereby favoring suppression of out-of-band SSB phase noise. By adaptively changing loop bandwidth depending on whether a jammer is detected, performance requirements on sub-circuits within the PLL can be relaxed while still satisfying in-band residual FM and out-of-band SSB phase noise requirements. By allowing the VCO of the PLL to generate more phase noise due to the adaptive changing of loop bandwidth, VCO power consumption can be reduced.

Abstract: A device receives a signal and, prior to demodulating the signal determines whether carrier is present in the received signal based on the correlation depth of the received signal. The device determines a plurality of values for the received signal that indicate the amount of correlation in the received signal and detects the presence of the carrier in the received signal as a function of the plurality of values. The plurality of values can include autocorrelation values and prediction coefficients, wherein the autocorrelation values are estimated based on an autocorrelation function derived for the received signal, and the prediction coefficients are generated using a prediction model that is derived as a function of the autocorrelation values. The prediction coefficients can be summed to generate a decision statistic that is compared to a detection threshold to detect the presence of the carrier.

Abstract: A phase calibration circuit applied to at least one signal processing module group includes at least two phase calibration modules, a phase detection module and a filter module. An output node of a first phase calibration module is coupled to an input node of a first signal processing module, an input node of a second phase calibration module is coupled to an output node of the first signal processing module, and the first signal processing module receives a calibrated signal outputted from the first phase calibration module and generates a processed signal. The phase detection module is utilized for generating a phase error signal according to a calibrated signal of an Mth phase calibration module, where M is an integer equal to or greater than two. The filter module is utilized for generating at least a first and a second phase calibration signal according to the phase error signal.

Abstract: Certain embodiments of the present invention provides a system and method for SAP FM demodulation. The system includes a bandpass filter for isolating the SAP signal, a Hilbert filter to produce a copy of the SAP signal phase shifted by 90 degrees, an FM demodulator for demodulating the SAP signal using the phase shifted SAP signal and a delayed SAP signal, and a lowpass filter to eliminate noise from the FM demodulated SAP signal. The system may also include an automatic gain control for normalizing amplitude of FM demodulator input signals. The digital FM demodulator uses a simplified approximation using non-unity delay for simplified demodulation of frequency modulated signals.

Abstract: A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.

Abstract: A QP detection unit includes digital circuit elements. There is provided a digital QP detector which detects an electric power signal Vi, which is an input signal, and outputs a detection signal Vo. The digital QP detector includes a register which records input digital data, a first multiplier which multiplies the digital data recorded in the register by a first coefficient, a second multiplier which multiplies the digital data recorded in the register by a second coefficient, an adder which adds the electric power signal Vi and the output from the first multiplier to each other, a comparator which compares the level of the electric power signal Vi and the level of the detection signal Vo, and a first switch which switches the digital data to be fed to the register between the output from the adder (Vi>Vo) and the output from the second multiplier (Vi<Vo) based on a comparison result of the comparator.

Abstract: A single chip radio transceiver includes circuitry that enables received wideband RF signals to be down-converted to baseband frequencies and baseband signals to be up-converted to wideband RF signals prior to transmission without requiring conversion to an intermediate frequency. The circuitry includes a low noise amplifier, automatic frequency control circuitry for aligning a local oscillation frequency with the frequency of the received RF signals, signal power measuring circuitry for measuring the signal to signal and power ratio and for adjusting frontal and rear amplification stages accordingly, and finally, filtering circuitry to filter high and low frequency interfering signals including DC offset.

Abstract: Methods and apparatus are provided for receiving a first signal and generating an output signal indicative of radio data system (“RDS”) information. A receiver circuit of the invention can include mixer circuitry, lowpass filter circuitry, downsampler circuitry, and decoder circuitry. Advantageously, the receiver circuit can operate entirely within the digital domain, promoting interoperability with digital frequency modulation (“FM”) demodulator circuitry.

Abstract: An apparatus for communications includes, a front processor for outputting a digital formatted base band signal with quadrature demodulating a modulated signal; an interpolation processor for interpolating to adjust a phase error in accordance with sampling timing on the basis of the base band signal outputted from the front processor and for creating and outputting a base band signal synchronized with the sampling timing; and a back processor for wave-shaping the base band signal outputted from the interpolation processor and for outputting. And the apparatus changes tap coefficients which are supplied to an FIR filter in the interpolation processor on the basis of the modulated signal inputted therein, and can appropriately control the bandwidth characteristic of interpolators.

Abstract: A packet detector for a multi-band orthogonal frequency division multiplexing system includes a plurality of packet detection units each corresponding to a time frequency code for detecting packets according to a spreading sequence of the time frequency code, a comparison unit for comparing correlation values provided by division units of the plurality of packet detection units, and a packet decision module for determining a time frequency code and size of a fast Fourier transform sampling window according to output signals of the comparison unit, allowing a frequency band to be selected and synchronization to be executed.

Abstract: In one embodiment, a method is provided of communicating in a wireless communication system. The method comprises (a) setting a decrement burst variable to be equal to a predetermined number representing a number of bursts of data from which to prematurely decode a USF codeword, (b) receiving a received burst of data comprising USF related data related to a portion of a USF codeword, (c) extracting said USF related data from said equalized received burst of data, (d) determining if a burst number variable is equal to said decrement burst variable, (e) incrementing said burst number variable and repeating (b) through (d) if said burst number variable is not equal to said decrement burst variable, and (f) decoding said USF codeword if said burst number variable is equal to said decrement burst variable.

Abstract: A near field RF communicator has an IQ demodulator (100) and a demodulator processor (205) that identifies a transition between logical states on the basis of either: 1) a magnitude obtained by adding a first value representing a difference between positive and negative peaks in the in-phase modulation and a second value representing a difference between positive and negative peaks in the quadrature phase modulation; or 2) whether a combined value representing a rate of change in the in-phase modulation and in the quadrature phase modulation exceeds a threshold.

Abstract: The IFBPF (80) can variably set a passband width (WF) and an attenuation slope (KF). The bandwidth control circuit (102), which is constituted in hardware, controls the WF in accordance with the receiving state, which is composed of a combination of the receiving electric field intensity, the modulation degree, and the intensity of the adjacent-channel interference. A microcomputer (54) controls the KF on the basis of a program stored in a nonvolatile memory (60) and finely adjusts the effective passband width. Control of the WF contradictory for prevention of audio distortion and control of adjacent-channel interference is required when high modulation and adjacent-channel interference exist in a weak electric field state, and the setting becomes difficult. In this particular case, a configuration in which the KF can be modified by a program allows an advantageous receiving state to be readily obtained.

Abstract: This disclosure addresses providing gigabit-rate data transmission over wireless radio links, using carrier frequencies in the millimeter-wave range (>30 GHz). More specifically, a circuit for detection of amplitude-shift keyed (ASK) or other amplitude modulations (AM) which can be easily incorporated into an integrated circuit receiver system is described, making the receiver capable of supporting both complex IQ modulation schemes and simpler, non-coherent on-off or multiple-level keying signals. Several novel radio architectures are also described which, with the addition of a frequency discriminator network, have the capability of handling frequency shift keyed (FSK) or other frequency modulations (FM), as well as AM and complex IQ modulation schemes.

Abstract: An FM tuner that has a multipath reception detection unit and an adjacent-channel interference detection unit while reducing expansion of the scale of the circuit is available. A control signal for a stereo separation level is generated on the basis of a signal SM-DC corresponding to a reception field strength and of a signal SMP corresponding to a multipath noise component. The SMP is extracted from a fluctuation component signal SM-AC from an S-meter circuit 92 by a multipath noise extraction circuit 104. The multipath noise extraction circuit 104 used for control of the stereo separation level is shared as a portion of the circuitry for detecting the multipath signal reception state. A multipath reception detection unit 108 compares the SMP with a threshold value to detect a multipath reception state.

Abstract: Carrier frequency detection for an N-ary modulated signal is achieved by digitizing the N-ary modulated signal, frequency shifting the digitized N-ary modulated signal to prevent aliasing, raising the frequency-shifted signal to the Nth power, transforming the raised signal to frequency domain data and determining an initial maximum frequency peak, iteratively fine shifting the frequency of the N-ary modulated signal around the initial maximum frequency peak and repeating the raising, transforming and determining steps to obtain a plurality of maximum frequency peaks, and calculating the carrier frequency from the maximum frequency peaks and the total related frequency shift.

Abstract: Systems and techniques for digital processing of FM stereo signals are described. A carrier signal such as a 38 kHz carrier may be recovered and used to process a difference signal such as a left minus right signal. The left minus right signal and a left plus right signal may be used to generate separate left plus right signals.

Abstract: A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.

Abstract: A radio receiver having multiple AM/FM tuners. A first tuner and a second tuner may be connected with an antenna for generating a first and second composite audio output signal. A dual input digital signal processor may be connected with the first tuner and the second tuner. The first and second composite audio output signals are processed by the dual input digital signal processor to generate a first audio output signal and a second audio output signal. A first audio power amplifier may be connected with the dual input digital signal processor for receiving the first audio output signal and a second audio power amplifier may be connected with the dual input digital signal processor for receiving the second audio output signal.

Abstract: In one embodiment, the present invention includes a method for determining process corner information of an integrated circuit (IC) and controlling at least one analog current for at least one analog circuit of the IC based on the process corner information. More specifically, if the process corner information is indicative of a fast corner IC, the analog current may be scaled down. At the same time that the analog current is scaled down, a current consumption level of digital circuitry of the IC may increase. In this way, overall power consumption of the IC may be reduced to the extent that the analog current(s) are scaled.

Abstract: A method and apparatus for power conservation is provided for a multi-mode wireless communication device (100) capable of operating in a plurality of networks, each of the plurality of networks having a network signal with predetermined spectral characteristics. The wireless communication device (100) includes a variable bandwidth signal detector (140), a threshold detector (145), and a controller (120). The variable bandwidth signal detector (140) receives radio frequency (RF) signals and defines a detection bandwidth for signal detection. The threshold detector (145) is coupled to the variable bandwidth signal detector (140) and detects a network signal within the RF signals in response to determining whether a signal is present within the detection bandwidth having a signal strength greater than a predetermined signal strength.

Abstract: The frequency of an RF signal to be transmitted is modulated at the transmitting unit, and the modulation information is used by the receiving unit to filter out any unwanted noise. The modulation information may be used to retrieve associated filter coefficients that are used by the receiver to filter out the noise. Accordingly, for each transmit frequency, a multitude of filter coefficients stored in a memory are applied by the receiver to filter out the noise. The filtering operation may be performed after the received signal is downconverted from an RF to an audio signal.

Abstract: An object of the present invention is to provide a radio receiver and a method for detecting carrier waves which make it possible to detect carrier waves for an IBOC type hybrid broadcast reliably. A radio receiver for receiving carrier waves for hybrid broadcasts which are arranged so as to be adjacent to and located on both sides of carrier waves for analog broadcasts in frequency bands includes a tuner for tuning to a broadcast frequency, and a controller for setting a center frequency of shift frequency in a range where carrier waves for an analog broadcast can be detected and allowing the tuner to tune to the set shift frequency.

Abstract: A signal reception time period detector is disclosed. The signal reception time period detector includes a signal separation portion configured to decompose into signal components a received signal composed of plural signals which are overlapped at least partially in a period during which the received signal is transmitted, and a reception time period detection portion configured to detect a time period during which the signal components are received based on the signal components.

Abstract: A carrier detecting circuit which generates a carrier detection level by integral action based on a reception signal and detects using the carrier detection level whether a carrier exists is disclosed and includes an integration capacitor that is charged and discharged using a difference current between a current charged from a charging circuit and a current discharged to a discharging circuit, where the charging circuit and the discharging circuit are provided in an integrator which performs the integral action.

Abstract: An envelope detector that does not generate an undesirable DC offset at its DC output signal. An envelope detector according to the present teachings includes a circuit for performing a DC level shift on an AC input signal applied to the envelope detector such that a magnitude of the DC level shift is proportional to a peak envelope of the AC input signal.

Abstract: The present disclosure provides a receiver for receiving a narrow frequency deviation frequency modulated or phase modulated base band signal including a mixer for mixing the received narrow frequency deviation signal to generate an intermediate frequency signal, a band pass filter for filtering the intermediate frequency signal, and a narrow band discriminator circuit that performs a time domain expansion of the modulation deviation of the intermediate frequency signal and discriminates the base band signal.

Abstract: The communication performance of a radio communication system is improved while keeping short time necessary for attaining synchronization. A low noise amplifier is selectively provided with one of an input signal supplied from the outside of the system and an oscillation output signal of a local oscillator. A mixer integrates the oscillation output signal of the local oscillator and an output signal of the low noise amplifier. An intensity discriminating unit discriminates the signal intensity of an output of the mixer. In a first state, the low noise amplifier amplifies the oscillation output signal of the local oscillator, and a control unit learns a frequency band of the low noise amplifier for maximizing the signal intensity on the basis of the discrimination result of the intensity discriminating unit. In a second state, the low noise amplifier is set to the frequency band learned in the first state and amplifies the input signal.

Abstract: A tire air pressure detection system, able to prevent a strong electric field or strong radio interference from affecting transmitters and causing mistaken data relating to tire air pressure to be sent out and a driver from being mistakenly warned, having transmitters with controllers, detection circuits, and sensing units and a receiver, the controllers stopping detection signals from being sent to the receiver at current transmission timings when the detection circuits detect a strong electric field or radio interference in the interval from a previous communication timing to a current communication timing, whereby even if the strong electric field or radio interference affects detection signals from sensors provided at the sensing units, the transmitters can be prevented from sending out mistaken data relating to tire air pressure.

Abstract: A receiver includes a processor and an RF bridge. The RF bridge is coupled to the processor to receive a reference signal from the processor. The RF bridge includes first and second frequency converters coupled to respective first and second antennas. The RF bridge also includes a third frequency converter coupled to outputs of the first and second frequency converters. In an alternative receiver the processor is coupled to receive an information signal from the RF bridge. The processor includes a digital frequency source to generate the reference signal based on a signal from a clock source and circuitry to detect a frequency difference from the information signal based on the signal from the clock source. In a variant, the circuitry to detect includes a first Fourier transformer having a first center frequency and a second Fourier transformer having a second center frequency different than the first center frequency.

Abstract: Apparatus for reducing DC offset in a signal path of a conversion system comprising a front end circuit for providing an input signal having an a DC offset; an amplifier system coupled to the front end circuit to receive and amplify the input signal; a multi-bit sigma delta modulator for receiving the input signal from the amplifier system and providing a first bit quantizer; a DC adapt circuit coupled to the sigma delta modulator for receiving the first bit quantizer from the sigma delta modulator and for providing an operation to reduce DC offset; a digital to analog converter (DAC) coupled to the digital DC adapt circuit to provide an analog signal representative of the DC offset correction to the input of the amplifier system, wherein the digital DC adapt circuit and the DAC form a feedback path originating at the first bit of the multi bit sigma delta modulator to the input of the amplifier system.

Abstract: An aspect of the present invention provides a receiving circuit that includes a mixer configured to receive a signal and a local signal to mix the signals, the mixer configured to convert the signals into an intermediate frequency signal, an IF filter configured to filter the intermediate frequency signal outputted from the mixer, an IF amplifier configured to amplify a band of the intermediate frequency signal outputted from the IF filter, and a demodulation circuit configured to receive a signal outputted from the IF amplifier to carry out demodulation, wherein a part of the demodulation circuit is disposed outside of the receiving circuit.

Abstract: An AM receiver incorporates an antenna, a transistor, a current source, and a power supply. The antenna is connected to a gate electrode of the transistor and through a link to a signal earth. In operation, the antenna receives radiation and generates a corresponding input signal which propagates to the gate electrode. The transistor is operable to process the input signal in two steps, namely to reflectively amplify the input signal to generate a correspondingly reflectively amplified input signal at the gate electrode in a first step, and amplitude demodulate the amplified input signal in a second step. The transistor is operable in a non-linear region of its current/voltage characteristic whereas it simultaneously provides reflective amplification and signal demodulation, namely the two steps occur simultaneously.

Abstract: A receiver window design algorithm (210) is developed which minimizes the noise power of the demodulated multicarrier signal. The windows are effective on a variety of different channels and noise sources. Receiver windowing is a computationally efficient technique for reducing noise spreading in multicarrier communication systems.

Abstract: A method and apparatus for reducing the number of erred bits in the decoded signal by using a channel decoder whose transfer characteristic is matched to the transfer characteristic of the MIMO detector. This means that the curve of the transfer characteristic of the MIMO detector is 1) above the curve of the reflected transpose of the transfer characteristic of the channel decoder for about 95% of the curve, and 2) close to the reflected transpose of the curve of the transfer characteristic of the channel decoder. Particularly, an LDPCC decoder can be used as the channel decoder and can be matched to the MIMO detector by matching 1) the transfer characteristic of the LDPCC decoder's CND to 2) the transfer characteristic of a combination of the MIMO detector and the LDPCC VND. Furthermore, the LDPCC can be similarly matched to any appropriate detector in addition to or instead of the MIMO detector.

Abstract: A signal-to-noise estimator is provided for estimating the signal-to-noise ratio in wireless fading channels. The estimator can be applied to likelihood ratio estimation of turbo decoders in third generation wide-band code division multiple access (WCDMA) systems. Time-multiplexed samples of pilot symbols from a wireless receiver are supplied to the estimator to obtain individual estimates of signal power and/or noise power. The estimator uses a de-correlating filter in which the coefficients are known functions (such as eigen-vectors) of the auto-correlation matrix for a wireless channel. The decorrelating filter is used by the estimator to map an observation vector into a set of statistically independent samples. The energy of each vector component is computed individually and combined to produce an aggregate sum for the vector. The aggregate sum can be subtracted from the pilot tone power in order to produce an estimate of noise power.

Abstract: Certain embodiments of the present invention provides a system and method for SAP FM demodulation. The system includes a bandpass filter for isolating the SAP signal, a Hilbert filter to produce a copy of the SAP signal phase shifted by 90 degrees, an FM demodulator for demodulating the SAP signal using the phase shifted SAP signal and a delayed SAP signal, and a lowpass filter to eliminate noise from the FM demodulated SAP signal. The system may also include an automatic gain control for normalizing amplitude of FM demodulator input signals. The digital FM demodulator uses a simplified approximation using non-unity delay for simplified demodulation of frequency modulated signals.

Abstract: A resonant tunneling diode or diode array oscillator (10) including a resonant diode (11) is coupled to a millimeter-wave source (14) and a quench generator (16) for periodically quenching the oscillations so that the average oscillation time of the oscillator is proportional to signal strength of the source (14). The signal source can be from an antenna such as a dipole or tapered slot line antenna.