|
Match
|
Document |
Document Title |
|
|
6301312 |
Bandpass phase tracker with hilbert transformation before analog-to-digital conversion
The tuner in a digital TV receiver converts received signal to a penultimate intermediate-frequency signal. Penultimate local oscillations are supplied in a first phasing and in a second phasing in...
|
|
|
6301311 |
Non-coherent, non-data-aided pseudo-noise synchronization and carrier synchronization for QPSK or OQPSK modulated CDMA system
A non-coherent method for (PN) code synchronization and eliminates the need for prior clock synchronization between a transmitter and receiver. The method further eliminates any need for prior...
|
|
|
6298100 |
Phase error estimation method for a demodulator in an HDTV receiver
A receiver for processing a VSB modulated signal containing terrestrial broadcast high definition television information and a pilot component includes a carrier recovery network (22; FIG. 3) that...
|
|
|
6297691 |
Method and apparatus for demodulating coherent and non-coherent modulated signals
A receiver receives modulated message signals in non-coherent FSK and coherent 8PSK protocols. A selectively configurable processor demodulates the message signals, and includes a demodulator that...
|
|
|
6289061 |
Wideband frequency tracking system and method
A wideband receiver automatic frequency control (AFC) system which combines multipath or diverse antenna signals, before the carrier frequency error is determined, is provided herein. Rather than...
|
|
|
6285721 |
Method for assisting simple synchronization to the carrier of a dispersed-energy QPSK signal
A method for simple synchronization of a receiving device to a transmitting device for a transmission of a dispersed-energy QPSK signal. The signal is composed at the transmitting end of two mixed...
|
|
|
6282500 |
Accumulated phase measurement using open-loop phase estimation
An apparatus and method for generating an accumulated phase measurement of a communications signal over a predetermined time interval. A frequency estimate of the signal is generated; the frequency...
|
|
|
6278745 |
Receiver having a memory based search for fast acquisition of a spread spectrum signal
A GPS receiver having a fast time to lock to a GPS signal by storing a time period of an incoming GPS signal in a signal memory and rapidly comparing the signal memory against locations in a...
|
|
|
6278746 |
Timing recovery loop circuit in a receiver of a modem
A method and apparatus for timing recovery in modem receivers. The timing recovery circuit includes a voltage controlled oscillator for controlling the voltage controlled sampling frequency of an...
|
|
|
6275544 |
Baseband receiver apparatus and method
A base band receiver apparatus comprising an RF front end section, a pulse detection unit wherein modulated, ultra-short spread spectrum pulses are detected, and a data recovery unit wherein clock...
|
|
|
6269118 |
Signal carrier recovery process
A carrier recovery process for a received signal comprises estimating the signal carrier frequency, and estimating the signal phase after frequency estimating. During frequency estimating, signal...
|
|
|
6269128 |
Clock recovery control in differential detection
A digital demodulator for demodulating a digital-Modulated signal into received data using differential detection includes a clock recovery circuit where a phase of the clock is adjustable in steps...
|
|
|
6268767 |
Dual bit error rate estimation in a QAM demodulator
A quadrature amplitude modulation type demodulator having a dual bit error rate estimator unit that allows for high bit error rate measurements. The dual bit error rate estimator circuit uses...
|
|
|
6266377 |
Method of timing recovery convergence monitoring in modems
A method of timing recovery convergence monitoring in modems using an average phase error signal. The method involves continuously tracking the peak of the average phase error. The average phase...
|
|
|
6249180 |
Phase noise and additive noise estimation in a QAM demodulator
A QAM demodulator having a carrier recovery circuit that includes a phase estimation circuit and an additive noise estimation circuit which produces an estimation of the residual phase noise and...
|
|
|
6249179 |
Direct digital synthesis in a QAM demodulator
A quadrature amplitude modulation (QAM) type demodulator having a pair of direct digital synthesizer (DDS) circuits. The first DDS circuit is located in a baseband conversion circuit before a...
|
|
|
6249557 |
Apparatus and method for performing timing recovery
A timing recovery circuit is disclosed that prevents phase error over-compensation. The timing recovery circuit includes a phase scanner for determining when phase error over-compensation has...
|
|
|
6246717 |
Measurement test set and method for in-service measurements of phase noise
A system and method for in-service transmitter phase noise measurements determines phase nonlinearity by way of comparing unfiltered signal samples and regenerated reference signal samples to...
|
|
|
6232761 |
Frequency estimating system
An inverse modulator 21, a Fourier transform circuit 22 and a power converter 23 are provided for obtaining a power-frequency spectrum of the carrier wave of a received signal, which is subjected...
|
|
|
6219379 |
VSB receiver with complex equalization for improved multipath performance
A method and device for improving the reception of a vestigial-sideband (VSB) signal by reducing the loss of information at the band edges in severe multipath. This is achieved by using complex...
|
|
|
6219333 |
Method and apparatus for synchronizing a carrier frequency of an orthogonal frequency division multiplexing transmission system
A system for synchronizing a carrier frequency of an orthogonal frequency division multiplexing (OFDM) transmission apparatus, even when a carrier frequency offset is above a frequency bandwidth of...
|
|
|
6215835 |
Dual-loop clock and data recovery for serial data communication
A clock and data recovery circuit for use in a serial data communications channel includes two phase-locked loops, the two PLLs being coupled together through the use of a matched pair of voltage...
|
|
|
6215830 |
Carrier control loop for a receiver of digitally transmitted signals
A carrier control loop (1) for a receiver of digitally transmitted signals is disclosed comprising, in the direction of signal flow, a quadrature demodulator (3), a symbol recognition device (4), a...
|
|
|
6208617 |
Channel tracking in a mobile receiver
An effective receiver is achieved for situations where the receiver is mobile, and may be traveling at relatively high speed, and where the receiver's internal demodulation oscillator causes a...
|
|
|
6208201 |
Recovery of a carrier signal from a modulated input signal
The present invention relates to the use of complex non-linear elements in improvements to the recovery of a carrier phase reference from a modulated input signal where the modulation is in...
|
|
|
6204725 |
Circuit for demodulating digital signal undergoing different modulation schemes
A circuit for demodulating a signal having a temporal mixture of different modulation schemes applied thereto includes a synchronization-word-detection unit which detects synchronization words...
|
|
|
6198782 |
Estimation of frequency offsets in OFDM communication systems
Apparatus for estimating carrier and clock frequency offsets in OFDM systems employs a maximun likelihood estimator operation on the demodulated signals. The invention has the benefit of low...
|
|
|
6192088 |
Carrier recovery system
A digital carrier recovery system includes at least two modes of operation, namely, an acquisition mode and a tracking mode. The bandwidth of the carrier recovery loop filter is different for the...
|
|
|
6181750 |
Apparatus for estimating the frequency difference existing between the carrier frequency of a digital signal and the frequency of a receiver local oscillator
An apparatus estimates the frequency difference existing between the carrier frequency of a received digital signal and the frequency of a signal from a local oscillator contained in a receiver of...
|
|
|
6178197 |
Frequency discrimination in a spread spectrum signal processing system
The actual carrier frequency of a spread spectrum signal is found by tuning a pair of correlators to a pair of search frequencies and then correlating the spread spectrum signal against one or more...
|
|
|
6175591 |
Radio receiving apparatus
A radio receiving apparatus regenerates a clock synchronized to a symbol clock contained in a quadrature demodulated signal obtained by demodulating a multilevel quadrature modulated signal,...
|
|
|
6175600 |
System for detecting the presence of a digital signal carrier wave, and a receiver including such a system
The invention relates to a system for detecting the presence of a carrier wave in a digital signal that is available at a given frequency. The system delivers at least two baseband samples of the...
|
|
|
6169761 |
Method and transceiver using an improved protocol for a frequency hop communication system
A frequency hopping transceiver having a protocol for selecting a clear channel for exchanging QAM payload data signals. An energy level in a current channel is sounded by to determine whether it...
|
|
|
6163209 |
Demodulation of angle modulated carriers using a noncoherent reference
A technique for demodulating a message signal from an angle modulated carrier signal. A noncoherent, independent, periodic reference is generated to have a predetermined phase characteristic and...
|
|
|
6163276 |
System for remote data collection
A remote data collection system for collecting usage data from an endpoint includes a monitoring module coupled to the endpoint, the monitoring module having a wireless transmitter to transmit the...
|
|
|
6163208 |
One bit digital phase shift keyed carrier recovery and demodulator circuit
A phase shift keyed carrier recovery and demodulator circuit which includes a phase detector and subsequent feedback control loop circuitry which maintains an initial phase relationship. By...
|
|
|
6160443 |
Dual automatic gain control in a QAM demodulator
A QAM demodulator having a first automatic gain control circuit which outputs a first signal that is a function of the received signal, the first signal being used to control the gain of an...
|
|
|
6154510 |
Symbol timing recovery based on adjusted, phase-selected magnitude values
A digital communication receiver (10) includes a magnitude-based symbol synchronizer (38) which separates complex phase attributes from magnitude attributes. The phase attributes are processed by a...
|
|
|
6154506 |
Timing recovery and tracking method and apparatus for data signals
A timing recovery and tracking method and apparatus with respect to data signal in a digital communication system is provided. The method includes a step of setting a time window for making a...
|
|
|
6151367 |
Digital demodulator
A digital demodulator includes: a local oscillator for generating a predetermined frequency signal; a mixer for mixing an intermediate frequency (IF) signal with a local oscillation frequency...
|
|
|
6150978 |
GPS receiver having fast resolution of carrier phase ambiguity
A carrier ambiguity detector for resolving a 1/2cycle carrier phase ambiguity in an incoming GPS signal before the arrival of the next preamble by detecting a match or an inverted match between an...
|
|
|
6148039 |
System and method for harmonic interference avoidance in carrier recovery for digital demodulation
The present invention relates to an improved demodulator for locking onto and tracking a carrier. Harmonic frequencies are occasionally generated by demodulation circuitry. When this occurs, the...
|
|
|
6148040 |
Precoded gaussian minimum shift keying carrier tracking loop
An improved Gaussian minimum shift keying (GMSK) carrier tracking loop operating at baseband takes advantage of the orthogonality of precoded data GMSK signals and Laurent filtering to provide a...
|
|
|
6148037 |
Sampling timing phase error detector for VSB modulation signal
A sampling timing phase error detector in a VSB modulation signal which can realize a high speed transmission. The sampling timing phase error detector for detecting a timing phase error of a...
|
|
|
6137846 |
AFC circuit for a frequency scanning FSK receiver
An AFC circuit for a frequency scanning FSK receiver is so constructed that through put of data which can be transmitted is improved by shortening a header of a packet signal owing to the fact that...
|
|
|
6133785 |
False carrier lock receiver and associated methods for detection
A receiver includes a demodulator and a false carrier lock detector circuit for a quadrature amplitude modulated (QAM) signal. The demodulator includes a controllable oscillator and an offset...
|
|
|
6134276 |
Timing recovery system
A digital timing recovery system advantageously employs both demodulated I-phase and Q-phase components to more accurately locate the synchronization signal of an incoming VSB signal. The Q-phase...
|
|
|
6133802 |
Synchronous carrier recovery circuit and injection locked oscillator
A simple carrier recovery circuit capable of accurately detecting and synchronizing an incoming carrier frequency without the use of a phase locked loop (PLL) is provided. Instead of a PLL, the...
|
|
|
6125151 |
Carrier recovery circuit
The invention provides a carrier recovery circuit which reduces the amount of calculation processing recovered to renew the tap coefficients of an adaptive filter to achieve improvement performance...
|
|
|
6122328 |
Fast-acting Costas loop
A system and method using a Costas loop to effect accelerated convergence with minimal system complexity. The system comprises an in-phase-limiter and a quadrature-phase limiter, operatively...
|