Matches 401 - 450 out of 663 < 1 2 3 4 5 6 7 8 9 10 11 12 13 14 >
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5412693 Wholly-digital demodulation system for QAM signalling in low capacity links  
The present invention relates to a QAM signal demodulation system able to recover phase and frequency of the carrier and convert the signal to baseband, and to perform these functions when...
5410573 Digital phase-locked loop circuit  
A digital phase locked loop which incorporates a phase comparator which produces a phase deviation signal having a sinusoidal phase comparison characteristic rather than a sawtooth phase comparison...
5406593 Adaptive phase-locked loop employing channel state information estimation from received signal phase angles  
A method of estimating the quality of a communication channel from a differential phase angle between a received signal and the corresponding transmitted phase angle employs determining a signal to...
5402442 Receiving device for receiving and demodulating spread spectrum-modulated GPS wave  
A receiving device for receiving spread spectrum-modulated GPS signal transmitted from GPS (Global Positioning System) satellites to the earth. Received GPS signals are converted into IF signals...
5402446 FSK receiver having a PLL local oscillator operable in intermittent operation in accordance with its phase locked state  
In an FSK receiver of double superheterodyne type for receiving an FSK modulated wave and comprising a PLL local oscillator (10) for ensuring a phase-locked loop to produce a first local...
5400364 Decision-directed digital phase locked loop  
A decision-directed phase-locked loop for not synchronizing with opposite phases where the proper data of a PRS channel reproduced signal do not exist. The loop comprises a digital loop filter, a...
5398002 Automatic frequency control system by quadrature-phase in frequency or phase demodulating system  
A method and apparatus for digitally demodulating a phase or frequency modulated signal using a quadrature mixing circuit to mix the phase or frequency modulated signal with a frequency equal to...
5394441 Method and apparatus for digitally tracking highs and lows of a signal received by a radio communication device  
A method for tracking a received signal comprises the steps of setting (635) a counter (130) to a first value indicative of a first signal voltage, determining a center threshold of the received...
5388127 Digital timing recovery circuit  
An implementation efficient digital timing recovery circuit capable of being implemented without the use of multipliers. The circuit includes a voltage controlled crystal oscillator ("VCXO"), a...
5379223 Inertial measurement and navigation system using digital signal processing techniques  
An inertial measurement and navigation system using a multisensor which provides analog acceleration and rate information to an analog to digital converter whose digital output is processed by a...
5373247 Automatic frequency control method and circuit for correcting an error between a received carrier frequency and a local frequency  
An AFC method is used in a demodulator, which employs a 2 n -phase phase shift keying modulation system, where n is an integer greater than or equal to two, to correct an error between a received...
5365185 Frequency controlled loop for demodulating OOK and PSK signals  
A method and apparatus for producing a frequency-controlled loop in a phase-diversity receiver for demodulating received ON-OFF-keyed (OOK) and phase shift keying (PSK) signals, by feeding a...
5353311 Radio transmitter  
A radio transmitter suitable for a frequency hopping communication system which transmits a phase modulated signal with a minimum of spurious signals and phase noise. A direct digital frequency...
5347228 BPSK demodulator using compound phase-locked loop  
A BPSK demodulator having a compound phase locked loop, such as a Costas loop, is disclosed. An in-phase component, signal SI from a Costas loop demodulating section 10 is converted by a...
5341402 Automatic frequency control method and device for use in receiver  
An automatic frequency control method for use in a receiver mixes a received signal and a local oscillator signal to produce an intermediate frequency signal and converts the intermediate frequency...
5341105 Quadratore demodulator circuit utilizing automatic frequency control signal and method thereof  
A circuit for regenerating a carrier, through coherent detection and demodulation of a quadrature modulated wave, is controlled by an improved AFC control to prevent possible false pull-in. The...
5325401 L-band tuner with quadrature downconverter for PSK data applications  
L-band tuner stage is combined with a quadrature downconverter stage in a single shielded enclosure as an L-band-to-baseband PSK tuner suitable for receiving L-band signals from an LNB and...
5307021 Phase-error detecting circuit for QDPSK demodulator  
A phase-error detecting circuit for detecting a phase error of an output signal of the VCO in a QDPSK demodulating circuit in accordance with the Costas loop method is disclosed. The phase-error...
5296820 Coherent demodulator preceded by non-coherent demodulator and automatic frequency control circuit  
A non-coherent demodulator 1 multiplies a modulated intermediate frequency (IF) signal with a signal from a local oscillator 2 to produce a first pseudo baseband signal having frequency error. The...
5289508 Clock information transmitting device and clock information receiving device  
A clock information transmitting device coupled to a digital processing circuit which receives a transmission signal and generates a coded transmission signal includes a PLL circuit for generating...
5282227 Communication signal detection and acquisition  
The presence of a communication signal having a predetermined recognition pattern of symbols that occur at a predetermined rate (1/T) is detected by processing the communication signal to extract...
5272730 Digital phase-locked loop filter  
A digital filter for a phase-locked loop operates to compare the bit values of the data represented by the incoming pulse stream with patterns in that pulse stream known to produce bit shifting...
5271040 Phase detector circuit  
A digital phase detector circuit is designed for particular application with a phase-locked loop voltage controlled oscillator system for synchronizing the MFM synchronization pulses on a floppy...
5271039 Local oscillating device  
There is disclosed a local oscillating device useful for a communication system where frequency conversion is implemented to data signals received in a burst manner, particularly for INMARSAT STC-C...
5260975 Digital demodulator  
A digital demodulator wherein a phase difference is detected between a reference signal and an angle-modulated wave, the difference in frequency is detected between the angle-modulated carrier wave...
5249204 Circuit and method for phase error correction in a digital receiver  
A digital receiver, such as "C-QUAM" receiver (10), has phase error correction. In another form, a software program may be executed by a conventional digital signal processor to also implement...
5237287 Demodulating method and apparatus particularly for demodulating a differential phase-shift keying signal  
A method and apparatus are described for demodulating a modulated signal having a carrier component and a data component, in which the modulated signal is split into at least two parts one of which...
5235622 Clock recovery circuit with open-loop phase estimator and wideband phase tracking loop  
In a clock recovery circuit, a received APSK signal is sampled at a frequency N times higher than the transmitted clock in response to a first clock from a local clock source, and quantized into...
5233631 Device for recovering a carrier wave provided with a circuit for inhibiting dummy frequency acquisitions  
The invention concerns a device for recovering a carrier wave provided with a circuit for inhibiting dummy frequency hookings or acquisitions for phase-modulated digital signals in N states with a...
5230088 Radio transceiver and related method of frequency control  
A radio transceiver for use in data communications uses a single phase-locked loop to control the frequency of the receiver portion while simultaneously providing coarse control of the frequency of...
5224130 Signal detection apparatus  
A digital signal data retiming and clock extraction apparatus including a series of three data latches (111, 121, 131), connected in cascade, means for applying digital data signals to the first...
5222144 Digital quadrature radio receiver with two-step processing  
A digital signal processing (DSP) radio receiver employs a conventional analog RF tuner to produce an analog intermediate frequency. The receiver performs DSP functions of digitally sampling the...
5206601 Order statistic signal processor for estimating values of signal parameters and demodulating amplitude-, phase-, and frequency-modulated signals  
The order statistic signal processor obtains continuing estimates of amplitude, phase, or frequency of an input signal based on order statistics. By way of definition, the P'th order statistic for...
5204634 Phase-locked loop demodulator having loop filter controlled by lock detector  
A phase-locked loop demodulator comprises a mixer and a loop filter between an input and an output. A voltage-controlled oscillator is connected between its output and an input of the mixer. The...
5193103 Digital phase locked loop circuit  
An all-digital phase locked loop circuit is described in which a numerically controlled oscillator is driven at a multiple of a required output frequency; a counter is provided to divide the output...
5182761 Data transmission system receiver having phase-independent bandwidth control  
A data transmission system receiver is disclosed which receives a formatted data stream (302) and operates in one of at least a first bandwidth mode and a second bandwidth mode. The formatted data...
5182760 Demodulation system for phase shift keyed modulated data transmission  
A phase shift keyed telemetry system is disclosed, which is particularly adapted to demodulation of phase shift keyed signals where the medium of transmission is non-ideal, such that transitional...
5179578 Coherent demodulator for π/4 shifted QPSK signal  
A demodulator for coherent demodulation of a π/4 shifted QPSK signal includes a -π/4 phase-shift circuit in a conventional QPSK signal decision/feedback type Costas loop to alternately rotate the...
5175729 Radio with fast lock phase-locked loop  
A communication device (508) for use in a Time Division Multiplex (TDM) communication system (500) includes a transmitter, a receiver, and a frequency scanner for quickly scanning the radio...
5173927 Frequency detector system on a digital phase locked loop  
A frequency detection system is based on a digital phase locked loop, the detection system being especially suitable for use in noisy environments like supervisory audio tone (SAT) detection in...
5157694 Coherent PSK demodulator using bit error rate and S/N ratio to establish synchronization  
In a coherent M-ary PSK demodulator, an M-ary PSK detector demodulates a received M-ary PSK modulated convolutional code with a carrier recovered by a voltage-controlled oscillator to produce first...
5150070 Demodulator for biphase, suppressed-carrier PSK signals  
A demodulator for biphase, suppressed-carrier PSK signals, in particular useful for the demodulation of digital information transmitted as an auxiliary information in radio transmission channels,...
5148450 Digital phase-locked loop  
An external digital phase locked loop for use in connection with a conventional serial communication controller is driven by a clock whose frequency is ten times the nominal data rate. Bit cells...
5142555 Phase detector  
Jitter attenuators (100) with a phase detector (104) to control a crystal oscillator to remove jitter wherein the phase detector includes both a sequential phase/frequency detector (200) of low...
5131014 Apparatus and method for recovery of multiphase modulated data  
A method and apparatus are provided for recovering multiphase modulated data. A signal pulse of a fixed duration is generated upon the transition of a first phase component of a multiphase...
5128626 Coherently demodulating arrangement including quasi-coherent demodulator for PSK signals  
An arrangement for coherently demodulating PSK (phase-shift keying) signals, includes a quasi-coherent demodulator which implements coarse coherent demodulation on an incoming PSK-modulated IF...
5121071 Lock detector for unbalanced QPSK demodulators  
A lock detector circuit (60) for demodulators of UQPSK signals I and Q has signal processing circuits for forming the signals: A=6I 2 Q 2 -I 4 -Q 4 ; B=4(I 2 -Q 2 ). A switch (19) is...
5117195 Data referenced demodulation of multiphase modulated data  
A data referenced demodulator is provided for recovering differentially encoded multiphase modulated digital data such as QPSK modulated audio data. An analog carrier containing the differentially...
5115454 Method and apparatus for carrier synchronization and data detection  
The present invention is directed to circuitry for achieving an improved carrier synchronization (i.e. estimation of carrier's phase) and data detection for digital data, suppressed carrier...
5093847 Adaptive phase lock loop  
An adaptive phase lock loop for jitter tracking. A filter in the adaptive PLL has coefficients that are automatically adjusted to minimize the error signal. The first block of the adaptive PLL is a...
Matches 401 - 450 out of 663 < 1 2 3 4 5 6 7 8 9 10 11 12 13 14 >