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7627053 |
Apparatus and method for driving a pulse width modulation reference signal
An apparatus for driving a pulse width modulation reference signal includes: (a) A converting unit receiving an input signal at an input locus and presenting an output current at an output locus....
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7606321 |
System and method for simplifying analog processing in a transmitter incorporating a randomization circuit
The system and method enable simpler analog processing in a transmitter by reducing the number of bits in a digital signal through delta sigma modulation. Selection of current sources in a digital...
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7542521 |
Direct-conversion frequency mixer
Provided is a direct-conversion frequency mixer for down converting a radio frequency (RF) signal into a baseband signal, in which a single phase RF signal and a quadrature location oscillation...
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7519134 |
Method and apparatus to determine phase difference between a received analog signal and a reference signal based upon a local oscillator
An apparatus and method for use by a receiver in decoding information sent by phase-shift keying over a carrier frequency is disclosed. The method is well suited for use with power line carrier...
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7508889 |
Digital apparatus for soft detection of multi-chip DBPSK signals
A system for implementing the soft decision of a 3-chip differential binary phase shift keying (DBPSK) optical signal using digital components. Pair-wise comparisons of three differentially...
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7498964 |
Analog interface for digital instrumentation
Nuclear spectroscopy systems have improved over the course of time especially with the advent of digital pulse processing. One disadvantage of digital processing, however, is that it has eliminated...
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7463108 |
Active 90-degree phase shifter with LC-type emitter degeneration and quadrature modulator IC using the same
An active 90-degree phase shifter with LC-type emitter (source) degeneration is provided, which is practiced in an integrated circuit. The phase shifter comprises a first differential amplifier,...
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7415078 |
Demodulation for phase modulation
A method and pre-processor for processing a MCPM signal including a phase multiplier for multiplying a MCPM signal by a scaling factor. The pre-processor also includes a frequency shifter for...
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7369623 |
Apparatuses to simultaneously distribute clock signals and data on integrated circuits, interposers, and circuit boards
A technique is described for simultaneously and synchronously transmitting digital data and a clock signal in a digital integrated circuit, circuit board, or system. The technique is based on the...
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7342872 |
Differential OFDM using multiple receiver antennas
Systems and methods for optimally receiving differential encoded OFDM signals via multiple antennas. These techniques may exploit spatial diversity without knowledge of channel characteristics....
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7190736 |
Technique to simultaneously distribute clock signals and data on integrated circuits, interposers, and circuit boards
A technique is described for simultaneously and synchronously transmitting digital data and a clock signal in a digital integrated circuit, circuit board, or system. The technique is based on the...
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7145966 |
Signal quality estimation for continuous phase modulation
A received continuous phase modulation (CPM) signal (which is formed with a set of pulse shaping functions) is approximated as a phase shift keying (PSK) modulated signal (which is formed with just...
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7143013 |
Reliable symbols as a means of improving the performance of information transmission systems
All practical communication channels impose some type of corruption on received data through inter-symbol interference (ISI). ISI corruption is particularly acute in high-order constellation...
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7110923 |
Fast, blind equalization techniques using reliable symbols
A fast equalization technique is disclosed for systems using high-order constellations where symbols have been corrupted by data correlated noise (ISI). The technique permits ISI estimation to...
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7106804 |
Method of and system for modulating and demodulating a communication signal using differential quadrature phase shift keying (DQPSK)
A system for and method of modulating and demodulating a communication signal using differential quadrature phase shift keying (DQPSK) can include, upon receiving an inbound communication signal,...
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7016425 |
Quasi-differential modulation/demodulation method for multi-amplitude digital modulated signals and OFDM system
The invention proposes the separate processing of the phase and amplitude of multi-amplitude digital modulation techniques, such as a QAM. The phases are differentially modulated and the amplitudes...
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6990627 |
Digital radio communication system for communicating M-ary modulated error detection units
A coding section 101 performs error detection coding of data for each predetermined error detection unit, and an M-ary modulation section 102 arranges data belonging to a plurality of error...
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6985531 |
Dual domain differential encoder/decoder
A method and apparatus that differentially encodes and decodes data symbols in dual domains is taught. Data packets are encoded, transmitted, and decoded during a plurality of symbol intervals on a...
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6973142 |
Timing synchronization for M-DPSK channels
The present invention discloses an improved method of timing synchronization with transmitted data packets in a receiver on a communication channel using differential phase shift keying (DPSK)...
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6956910 |
Fast transmitter based on table lookup
A method of increasing the speed of a transmitter by storing in look-up tables, modulation, spread, over-sampled and filtered samples of modulated data bits having an I and Q. The bits I and Q are...
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6850572 |
Encoding/decoding apparatus and method for orientation interpolator node data
An encoding/decoding apparatus and method for an orientation interpolator node are provided. The encoding/decoding apparatus for an orientation interpolator node, which provides rotational...
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6834089 |
Device for computing tangent angles and associated DQPSK decoder
A tangent angle computation device and associated DQPSK decoder. The computation device uses an eight-bit divider and a four-quadrant technique for finding a quantized angular value from an...
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6748030 |
Differential phase demodulator incorporating 4th order coherent phase tracking
Demodulating a DPSK encoded data signal. The received signal has a symbol tracking value determined in a synchronization circuit. Doppler error in the signal is estimated. The signal, the symbol...
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6639953 |
Apparatus and method for efficient binary phase shift key data demodulation
A binary phase shift key demodulator ( 64 ) demodulates a signal conveying bits. A vector computation component ( 88 ) computes an I, Q vector associated with a reference bit and computes an I, Q...
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6625231 |
Adaptive phase demodulation
Based on changing reception conditions, a wireless receiver adapts its demodulation method during active communications. Phase errors detected in the received signal indicate current reception...
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6621863 |
Equalizing apparatus combining amplitude error with squared envelope error according to variable weights
An equalizer providing a filtered signal to a data decision unit calculates an amplitude error signal by comparing the filtered signal with the data signal output from the data decision unit, and...
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6590945 |
Method and apparatus for frequency offset compensation
A simplified method for frequency offset estimation in a TDMA cellular PCS environment using π/4-shifted DQPSK comprises the steps of multiplying a complex conjugate of a received complex-valued...
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6567474 |
Digital wireless phone/modem jack capable of communications over the power lines using differential binary phase shift keying (DBPSK)
A system for communicating signals between a transmitter and a receiver using digital modulation techniques is provided. This invention is particularly adapted to meet the requirements of power...
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6487255 |
Information generation for coherent demodulation of differentially encoded signals
Methods and systems are provided which generate hard and soft values from signal samples of a differentially encoded signal by estimating channel coefficients associated with the received signal...
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6456669 |
Data communication method, transmitter, and cellular radio communication system
The present invention makes it possible to transmit data while reducing the influence of fading caused on a transmission path. When communication data is transmitted by using a plurality of...
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6456668 |
QPSK modulated backscatter system
In accordance with the present invention, a duplex radio communication system comprises an Interrogator which generates a radio signal to at least one remote Tag. The remote Tag receives the radio...
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6445746 |
IS-136&plus slot formation
A system and method for demodulating slots having a mixed slot formation including differential and coherently encoded slots is disclosed. The method includes pre-phase encoding data and a...
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6445745 |
Phase encoding methods for handling multiple phase modulated signals on a single channel
A method for phase encoding DPSK and N-PSK which maintains phase continuity and which does not require any reference symbols when using N-PSK. A sequence of known DPSK phases are encoded with...
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6373903 |
Apparatus and method for increasing the effective data rate in communication systems utilizing phase modulation
A system is disclosed for providing communication across a wireless network. The system includes a transmitter transmitting a modulated signal across a radio channel, wherein the transmitter...
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6363125 |
Non-coherent six-port receiver
According to the present invention a method and a receiver for high-frequency signals is provided. The receiver comprises a power divider ( 4 ) to divide a modulated RF input signal in at least two...
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6194977 |
State variable-based table-driven modulation signal generation
Dibits (i.e., pairs of bits) in an input data stream are converted into a modulation signal (e.g., a π/4-DQPSK modulation signal) using a technique that relies on pre-computed filter output values...
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6148024 |
FFT-based multitone DPSK modem
A system and a method for transmitting coded information bits using multitone techniques on a frame-by-frame basis. For transmission, coded information bits are mapped into differential phase...
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6118827 |
Apparatus for providing increased data rates within existing modulation systems
A method for increasing data rates within a modulated signal is disclosed. Initially, a first and second bit streams are interleaved together to form an interleaved output bit stream. The...
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6072785 |
Differential PSK signalling in CDMA networks
A method and a system for detecting a user signal in a CDMA network. (Coded) user message bits are grouped into successive groups. A differential phase is generated for each message bit group by...
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6016329 |
Method and apparatus for preamble-less demodulation
A method and apparatus for demodulating includes differential-detecting an input signal into which a unique word is inserted, correlating an output of the differential-detection and a data table...
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6002711 |
Spread spectrum communication system for error compensation of carrier frequency
A transmitter and a receiver of a spread spectrum communication system for compensating carrier frequency offsets between the transmitter and the receiver. The transmitter includes: a first...
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5987068 |
Method and apparatus for enhanced communication capability while maintaining standard channel modulation compatibility
In a radio communication system (100), enhanced communication capability is provided while maintaining standard channel modulation compatibility. At a transmitter (110, 200, 600), a first...
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5910968 |
Continuous phase modulation digital communication system
A digital communication system having a transmitter and a receiver. The receiver transmits a radio-frequency (RF) signal that is continuous phase modulated by digital data. The receiver having a...
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5828650 |
Combined modulation--and multiple access method for radio signals
The invention relates to the organization of phase references in a data transfer system based upon the multiplexing of orthogonal frequency components, when transmissions in the system are composed...
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5818878 |
Method and apparatus for decoding a diphase-coded digital signal
For decoding a diphase-coded signal the signal level is sampled with a sample signal of frequency equal to that of the bit clock pulse and each sample value is logically linked to the preceding...
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5818875 |
Modulation and demodulation method, modulator and demodulator
A modulation and demodulation method for communication between a transmitting side and a receiving side includes a step of at the transmitting side, producing a modulating signal, an amplitude...
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5786725 |
Reduced complexity maximum likelihood multiple symbol differential detector
A reduced complexity maximum likelihood multiple symbol differential detector which utilizes a maximum likelihood sequence estimation of the transmitted phase and does so by expanding the...
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5774502 |
Fully integrated data receiver and method for receiving on/off keyed AM/PDSK modulated signals
A data transmission system in which an on/off keyed (OOK) AM/DPSK modulated data signal with an on/off ratio exceeding about 80 dB which has been modulated on a carrier is received at a compact,...
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RE35829 |
Binary phase shift keying modulation system and/or frequency multiplier
A low cost spread spectrum modulator for BPSK, or Binary Phase Shift Keying capable of outputting the high modulation rate and suppressed carrier output needed in spread spectrum systems. The...
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5757856 |
Differential coder and decoder for pragmatic approach trellis-coded 8-PSK modulation
The invention relates to an 8-PSK differential coder for trellis-coded modulation and to a corresponding pragmatic decoder, enabling 90°, 180°, and 270° phase ambiguities to be lifted. The...
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