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6914945 |
Clock recovery circuit
In a clock recovery circuit for DTV using a VSB modulation method, if the frequency of the symbol clock is fs, since the frequency difference between the fs/2 component signal of the VSB signal and...
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6912244 |
Pilot frequency acquisition based on a window of data samples
Techniques to acquire the frequency of a signal instance based on a window of data samples covering a time period shorter than the time needed to achieve frequency lock. The window of data samples...
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6904098 |
Linear phase robust carrier recovery for QAM modems
In a QAM demodulator including an adaptive equalizer, a method of carrier tracking comprising the following steps is disclosed: (A) sampling a QAM signal received from a transmission channel; (B)...
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6898755 |
Method for increasing physical layer flexibility in cable modem systems
In a cable modem system, signals are transmitted upstream from a cable modem (CM) to a cable modem termination unit (CMTS) when the subscriber desires to communicate with the headend. The invention...
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6891898 |
System and method for recovering symbol timing offset and carrier frequency error in an OFDM digital audio broadcast system
The system for recovering symbol timing offset and carrier frequency error from an orthogonal frequency division multiplexed (OFDM) signal includes a receiver circuit for receiving an OFDM...
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6891907 |
Frequency offset correction system and correction method
A frequency offset correction system includes a phase shift estimation unit and correction unit. The phase shift estimation unit estimates a pilot phase shift from pilot signal data for a plurality...
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6891908 |
Portable radio system and portable radio equipment to be used in the same and frequency error prediction method used therefor
A portable radio system, a portable radio equipment to be used in the same and a frequency error prediction method can be adapted to large frequency error by making tap number smaller and frequency...
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6882373 |
Digital demodulating device in a digital TV receiver
A VSB demodulating device and method in a DTV receiver is disclosed, in which a VSB signal is received for independent carrier wave recovery and symbol clock recovery. An A/D converter samples the...
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6882691 |
Fine-frequency offset estimation
Orthogonal frequency division multiplexing (OFDM) receiver embodiments of the invention demodulate quadrature amplitude modulated (QAM) signals transmitted in the five GHz frequency band and...
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6882694 |
Apparatus, and associated method, for estimating frequency offset of a data symbol communicated in a communication system
Apparatus, and an associated method, for estimating frequency offset introduced upon symbols of a sequence communicated by a sending station to a data destination during operation of a...
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6879646 |
Quadrature amplitude modulation demodulator and receiver
A QAM demodulator comprises a timing synchronizer whose output is supplied via an adaptive equalizer to a carrier synchronizer, all of which are controlled by a controller. The timing synchronizer...
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6879815 |
Apparatus for extracting a carrier frequency
A frequency extractor extracts an input frequency of an input signal. The frequency extractor includes a frequency multiplier, first and second filters, a binary circuit and a frequency divider....
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6870892 |
Diversity receiver with joint baud clock recovery
First and second RF signals in the respective first and second channels of a multiple channel diversity receiver are processed jointly in a joint timing loop filter for baud clock recovery. The...
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6868131 |
Demodulation apparatus, broadcasting system and broadcast receiving apparatus
A demodulation apparatus that shortens demodulation time and performs efficient high-quality demodulation control. A digital signal generating section generates digital signals corresponding to...
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6862324 |
Data aided symbol timing system for precoded continuous phase modulated signals
Data aided carrier phase and symbol timing synchronizers are implemented at baseband as digital modulators isolating input signal inphase and quadrature component signals fed into inphase and...
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6856655 |
Timing recovery device and method for telecommunications systems
A timing recovery device for CAP/QAM modems includes an equalizer filter designed to monitor the movement of the filter coefficients within a memory buffer and to adjust the relative position of...
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6856656 |
Iterative carrier phase tracking decoding system
An iterative system for performing carrier phase tracking of symbols using a serial turbo decoder. Estimates of a buffered block of symbols are provided by a serial turbo decoder. Optionally,...
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6850576 |
Method and apparatus for reproducing timing, and a demodulating apparatus that uses the method and apparatus for reproducing timing
A base band signal is sampled, based on an asynchronous sampling clocking, to output two sampled data series. A transmission side complex symbol frequency generator generates a complex transmission...
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6847693 |
Method and device providing data derived timing recovery for multicarrier communications
A method and a device for providing timing recovery in a multicarrier transmission system is provided. The data derived timing recovery apparatus with the timing error controller adjusts the...
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6839388 |
System and method for providing frequency domain synchronization for single carrier signals
There is disclosed an improved system and method for providing frequency domain synchronization for a single carrier signal such as a vestigial sideband signal. The system comprises a...
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6834086 |
Demodulator and method for second harmonic cancellation
A demodulator circuit ( 10 ) having harmonic cancelling receives an input signal (IF) and generates an oscillator signal (OSC) in an oscillator circuit ( 14 ). The oscillator signal (OSC) is locked...
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6831942 |
MPSK spread spectrum communications receiver with carrier recovery and tracking using weighted correlation techniques
A multiple phase shift keying (MPSK) spread spectrum communications receiver uses weighted correlation techniques for carrier recovery and tracking. The receiver includes three subsystems: a...
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6829469 |
Method and a device for producing a signal
A method for producing an output signal ( 42 ) with a specific frequency from an input signal ( 40 ) received, the frequency of which changes quickly in steps of the size of an input frequency...
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6829311 |
Complex valued delta sigma phase locked loop demodulator
A complex valued delta sigma Phase Locked Loop (PLL) demodulator. The demodulator is a multiple stage demodulator. The first stage is a conversion stage which converts an incoming signal into a...
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6826238 |
Quadrature amplitude modulation receiver and carrier recovery method
Disclosed is a quadrature amplitude modulation (QAM) receiver and a carrier recovery method which receive a signal modulated by the QAM method and recover the frequency offset and phase jitter of...
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6819880 |
Loss of signal detection circuit for light receiver
An increase in the code error rate in a received signal is detected in a light receiver. An loss of signal detector circuit for a light receiver 20 comprises a main discrimination circuit 8 a ...
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6813321 |
Digital demodulator
A digital demodulator which will need no absolute phasing circuit is provided. A known-pattern BPSK signal generating circuit 6 generates the same known-pattern BPSK signal as a known-pattern...
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6810027 |
Multi-carrier transmitting apparatus and method
A multi-carrier transmitting apparatus and method is described, wherein a plurality of carrier signals are combined in the digital domain and supplied to a D/A converting means ( 3 ) for converting...
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6801589 |
Relative timing acquisition for a radio communications system
A method and apparatus are provided that allows a coarse timing approximation to be determined from analyzing only a portion of a received burst. The coarse timing can be refined by focusing on the...
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6795510 |
Apparatus and method for symbol timing recovery
A symbol timing recovery detector receives a sample stream, representing an input signal having successive symbol times sampled at successive sample times. The sample stream includes samples...
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6788749 |
Erasure based instantaneous loop control in a data receiver
A receiver for restoring a data signal from a data input signal, comprises a data detector and a control signal generator coupled to the data detector for controlling one or more loops in the data...
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6785345 |
Frequency dithering for DDS spectral purity
A frequency dither technique is used for reducing spurs due to phase increment errors in a direct digital synthesizer output sinusoid. The spurs for a desired output frequency are calculated and,...
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6781447 |
Multi-pass phase tracking loop with rewind of current waveform in digital communication systems
A demodulator demodulates a modulated signal waveform in a data communication system. A phase tracking loop tracks the phase of said modulated signal waveform and having an inner block decoder...
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6779162 |
Method of analyzing and filtering timing runs using common timing characteristics
A method of analyzing timing reports in a microprocessor design for quick identification of all negative timing paths has been provided. Timing paths are first grouped and saved in a list file. A...
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6771713 |
Data aided carrier phase tracking system for precoded continuous phase modulated signals
Data aided carrier phase and symbol timing synchronizers are implemented at baseband as digital modulators isolating input signal inphase and quadrature component signals fed into inphase and...
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6765972 |
Carrier synchronization type demodulator for PSK signal
A proximity IC card (PICC) which relates to and provides a carrier synchronization type demodulator, which is able to stably receive a PSK signal from a PICC and is enhanced in noise immunity, and...
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6760573 |
Frequency tracking using inner and outer loops
Techniques for inner/outer loop tracking that is stable and provides desirable loop convergence characteristics are disclosed. In one aspect, the contribution from any one inner loop to the...
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6760389 |
Data recovery for non-uniformly spaced edges
A shared data and clock recovery circuit including a clock synthesizer for generating sampling signals having different phases, a multiple transition detector for receiving a data stream and...
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6760076 |
System and method of synchronization recovery in the presence of pilot carrier phase rotation for an ATSC-HDTV receiver
There is disclosed a system and method for recovering a recurring data segment synchronization pattern in the presence of an arbitrary phase rotation of a pilot carrier by detecting and...
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6757336 |
Device and method for performing a carrier recovery
A method of receiving a signal and performing a carrier recovery, the method comprising the steps of: (a) receiving a signal Xk. (b) rotating Xk by a previous correction angle θk−1 to generate a...
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6751270 |
Carrier frequency recovery apparatus capable of simultaneously reducing frequency offset and phase error and method of the same
A carrier frequency recovery apparatus for simultaneously reducing a frequency offset and a phase error includes: a phase detector for estimating phase error of an I-channel and Q-channel signals...
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6751271 |
Detecting a carrier signal by using a power averaging circuit
The present invention provides an apparatus and method for detecting the presence of a carrier signal that is included in the reverse signals of a communications system. The present invention uses...
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6748029 |
Apparatus for restoring carrier wave and method therefor
A carrier wave restoring apparatus which is capable of restoring a carrier wave quickly and accurately by selectively controlling an operation of a matching filter. The carrier wave restoring...
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6744828 |
Receiving apparatus
An intermediate frequency signal S IF is demodulated and the noise component contained in a null portion (no-signal portion) is detected as the noise component contained in a signal of the...
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6735262 |
Apparatus and method of decision-directed carrier recovery based on LMS method
An apparatus and a method of decision-directed carrier recovery based on LMS method are provided. The apparatus of decision-directed carrier recovery based on LMS method includes frequency...
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6735263 |
Digital coherent envelope demodulation of FDMA signals
A method for coherent detection and demodulation of a FDMA signal, that is a superposition of amplitude modulated carriers, is provided. An array of special digital phase-locked loops (PLLs) is...
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6731697 |
Symbol timing recovery method for low resolution multiple amplitude signals
Symbol timing is performed by providing a histogram of samples of a signal for a predetermined number of symbol times. An average, weighted average, or other method is applied to determine an...
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6724835 |
Carrier tracking method
Systems and methods are described for carrier tracking. A center frequency of a signal is tracked by comparing spectral power contents of filtered versions of the signal. A receiver incorporates...
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6720824 |
Demodulation method and apparatus
A demodulation method and apparatus applicable to e.g., digital broadcast in accordance with the orthogonal frequency division multiplexing system (OFDM), in which synchronization of carrier...
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6721366 |
Phase tracking apparatus and method for continuous phase modulated signals
A method establishes a phase reference signal for trellis demodulating CPM modulated received signals by using phase reference signals and symbol timing estimates. Branch metrics signals...
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