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6108353 |
Demodulating apparatus
A demodulating apparatus according for demodulating a modulated signal obtained by modulating a plurality of carriers having different frequencies, includes a data demodulating circuit for...
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6091760 |
Non-recursively generated orthogonal PN codes for variable rate CDMA
A method and apparatus for constructing a series of PN code sets that can be used for multirate synchronous and quasi-synchronous CDMA systems. The construction technique produces PN codes that are...
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6088327 |
Method and circuit arrangement for improving carrier separation for the transmission of OFDM signals
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6084851 |
Demodulating method and apparatus, receiving method and apparatus, and communication apparatus
A selector that selects an orthogonally detected output signal of I channel and an orthogonally detected output signal of Q channel and that outputs the selected signals to a path for obtaining a...
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6075781 |
Flux density reduction in OCDMA satellite communication system
A spread spectrum CDMA communication system in which base stations communicate with a plurality of subscriber terminals located in different beams of a multi-beam satellite relay system. A base...
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6061342 |
Code division multiple access apparatus
A code division multiple access apparatus which is capable of high-speed synchronization, is simple in construction and, moreover, achieves reduced consumption of electric power during standby....
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6061387 |
Method and system for turbo-coded satellite digital audio broadcasting
A system and method for broadcasting an audio signal in a turbo-coded satellite digital audio broadcasting system is provided that utilizes the combination of a turbo coding system having code...
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6061327 |
Device and method for vector equalization of an OFDM signal
The present invention belongs to the field of transmission of a signal, using OFDM modulation (Orthogonal Frequency Division Multiplexing), from a transmitter to at least one receiver, via a...
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6058101 |
Synchronization method and system for a digital receiver
A synchronization system and method for obtaining frame, carrier, and sampling synchronization of an input OFDM modulated digital signal having a pseudoperiodic second symbol. The system includes...
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6038263 |
Method and apparatus for transmitting signals in a communication system
Different orthogonal codes (W x , W y ) are used to spread common pilot channels (Pilot A ) intended for transmission to a particular mobile station (106) within a coverage area (sector A) to...
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6035003 |
Apparatus for correcting frequency offset in OFDM receiving system
The disclosure describes an apparatus for correcting a frequency offset in a OFDM receiving system. The apparatus comprises a loop filter for receiving a predetermined phase value, multiplying the...
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6028888 |
Single-channel and multi-channel coherent demodulation devices with no pilot signal, and corresponding receiving system using a plurality of diversity paths
Coherent demodulation is effected in single-channel and multi-channel coherent demodulation devices without any knowledge of the transmitted signal (i.e. without any pilot signal). The phase shift...
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6021110 |
OFDM timing and frequency recovery system
A synchronizing apparatus for a differential OFDM receiver that simultaneously adjust the radio frequency and sample clock frequency using a voltage controlled crystal oscillator to generate a...
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5995483 |
Apparatus and method for upstream clock synchronization in a multi-point OFDM/DMT digital communication system
A multi-point communications system is set forth herein. The communications system includes a transmitter for transmitting OFDM/DMT symbols over a predetermined number of bins across a transmission...
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5995497 |
Method and apparatus for switching code division multiple access modulated beams in a satellite
In a code division switch in a satellite communication system each of a plurality of uplink CDMA modulated RF beams, each including a plurality of uplink traffic channels, are down converted to IF...
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5987005 |
Method and apparatus for efficient computation of discrete fourier transform (DFT) and inverse discrete fourier transform
The present invention significantly reduces the number of complex computations that must be performed in computing the discrete Fourier transform (DFT) and inverse DFT (IDFT) operations. In...
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5963591 |
System and method for stochastic characterization of a signal with four embedded orthogonal measurement data items
A signal processing system provides and processes a digital signal, generd in response to an analog signal, which includes a noise component and possibly also an information component representing...
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5959967 |
Digital transmission system
An orthogonal frequency division multiplex (OFDM) transmission system, e.g. for tranmitting data traffic over a telephone subscriber twisted pair loop, includes a transmitter for generating sets of...
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5946292 |
Method and digital receiver for receiving orthogonal frequency-division multiplexed signals
A digital receiver uses a local oscillator to down-convert an orthogonal frequency-division multiplexed signal that has been modulated by differential phase-shift keying, and performs further...
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5946326 |
Method and an equipment for transmitting a file-based multimedia and hypermedia service to a mobile receiver
An apparatus and a method for transferring an audio/video/data service from a transmission end to a reception end over a radio interface. The audio/video/data service includes one of audio...
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5943372 |
Orthogonal polarization and time varying offsetting of signals for digital data transmission or reception
A system for inducing rapid fading in wireless communication systems, such as digital radio and television transmission is described. Orthogonal polarization combined with time varying offsets are...
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5940365 |
AM data multiplexing modulation apparatus
An AM data multiplexing modulation apparatus for multiplexing a digital signal to an AM modulation signal without adversely affecting an AM sync detection output even if AM sync detection is...
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5926500 |
Reduced peak-to-average transmit power high data rate CDMA wireless communication system
A novel and improved method and apparatus for high rate CDMA wireless communication is described. In accordance with one embodiment of the invention, a set of individually gain adjusted subscriber...
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5914931 |
Method of initial frame synchronization using orthogonal frequency division multiplexing signals
An initial frame synchronization method for finding out the initial frame synchronization offset at a receiver using the orthogonal frequency division multiplexing signals by which any data is...
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5914933 |
Clustered OFDM communication system
A multicarrier communication system for wireless transmission of blocks of data having a plurality of digital data symbols in each block. The communication system includes a device for distributing...
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5910964 |
Code detection apparatus
A code detection apparatus, comprised of a unit for orthogonally detecting a spread spectrum modulated reception signal, a unit for applying phase compensation to the orthogonally detected signal...
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5909436 |
Random access orthogonal frequency division multiplex system and method
A random access protocol system and method for communicating between a mobile station and a base station in a multi-access digital radio communication system, including the steps of cyclically...
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5907582 |
System for turbo-coded satellite digital audio broadcasting
A system and method for broadcasting an audio signal in a turbo-coded satellite digital audio broadcasting system is provided that utilizes the combination of a turbo coding system having code...
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5867478 |
Synchronous coherent orthogonal frequency division multiplexing system, method, software and device
A synchronous coherent orthogonal frequency division multiplexing, SC-OFDM, system, method, software and device include a plurality of SC-OFDM transmitters and a plurality of SC-OFDM receivers....
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5862226 |
Automatic mode detection in digital audio receivers
The broadcast mode of the different ones set by the international standards for digital audio broadcasting (DAB) according to a coded orthogonal frequency division multiplexing scheme (COEFDM) may...
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5841806 |
Method and apparatus for the transmission of energy-scaled variable rate data
An apparatus for communicating variable rate data over a communication channel. A modulator that receive frames of user data each comprised of data symbols. The modulator repeats the data symbols...
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5818813 |
Orthogonal frequency division multiplexing transmission system and transmitter and receiver adapted to the same
Data sequences correspond to L different parameter sets (effective symbol length, guard interval length, the number of carrier waves) and transformed into parallel data by respective...
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5815488 |
Multiple user access method using OFDM
A communication method enables a plurality of remote locations to transmit data to a central location. The remote locations simultaneously share a channel and there is a high degree of immunity to...
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5812523 |
Method and device for synchronization at OFDM-system
A method of demultiplexing OFDM signals and a receiver for such signals. More particularly the method is concerned with synchronization in an OFDM receiver. A signal is read into a synchronization...
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5799038 |
Method for measuring modulation parameters of digital quadrature-modulated signal
The signal to be measured is converted into digital form and read into a memory 13 using a trigger as the reference, and a signal of a length 1/5 that of the signal to be measured, in the vicinity...
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5790615 |
Digital phase-lock loop network
A digital phase-lock loop network that provides input and output clock signals to a digital data receiving system generally, and particularly to a data buffer contained therein, is disclosed. The...
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5790515 |
Method and apparatus for sorting walsh indexes in a communication system receiver
A communication system receiver sorts through potential Walsh indexes and determines survivors for use in subsequent processing. The sort process is implemented in parallel with the subsequent...
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5774450 |
Method of transmitting orthogonal frequency division multiplexing signal and receiver thereof
An orthogonal frequency division multiplexing signal transmitted from the transmitting end to the receiving end intermittently includes a particular symbol S0 having a predetermined particular...
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5757767 |
Method and apparatus for joint transmission of multiple data signals in spread spectrum communication systems
A more efficient and less complex structure and method for combining multiple user channels onto a single carrier frequency in spread spectrum communication systems. A single transformation...
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5748610 |
Multi-application wireless direct sequence spread spectrum digital cellular telephone system
A wireless OCDMA communication system in which there is a cluster of base stations (BS), or radio fixed parts (RFP), which may in turn be controlled by a wireless cluster controller (WCC). The...
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5737256 |
Inverse discrete cosine transform apparatus
An 8-point inverse discrete cosine transform (IDCT) is decomposed into four 2-point IDCTs. The four 2-point IDCTs are implemented by four parallel-operating product-sum computing circuits. Each...
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5734639 |
Wireless direct sequence spread spectrum digital cellular telephone system
An exceptionally efficient operation is achieved through the use of orthogonal code divisional multiple access radio communication between a base station and a plurality of user handsets. Each user...
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5694389 |
OFDM transmission/reception system and transmitting/receiving apparatus
This invention improves the frequency acquisition range and the resistance to multipath interference. In a digital signal transmission system using OFDM, on the transmission side, some or all of a...
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5687165 |
Transmission system and receiver for orthogonal frequency-division multiplexing signals, having a frequency-synchronization circuit
Receiver and transmission system for orthogonal frequency-division multiplexing signals comprising a frequency synchronization circuit (116) which has a local oscillator (214) whose frequency is...
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5680388 |
Method and arrangement for dynamic allocation of multiple carrier-wave channels for multiple access by frequency division of multiplexing
The invention relates to a method and an arrangement for dynamic allocation of multiple carrier wave channels for multiple access by frequency division multiplexing. the invention provides a number...
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5675608 |
Synchronous transmitter and receiver of spread spectrum communication method
A synchronous transmitter and receiver utilizing a spread spectrum communication method includes a pseudo noise code generator for generating a preset pseudo noise (PN) code; a spectrum spreading...
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5642383 |
Audio data coding method and audio data coding apparatus
An audio data coding method of requantizing digital audio data in accordance with the hearing sense characteristic of the human being, comprises: the steps of calculating a quantization error;...
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5602832 |
Receiver device for code division multiplex communication system
In a CDM (code division multiplex) communications system a base station transmits a plurality of data signals on a common channel. Each data signal is provided with a spreading sequence, e.g. a...
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5596600 |
Standalone canceller of narrow band interference for spread spectrum receivers
A spread spectrum interference canceller includes a downconverter for amplifying and translating the received signal from the radio frequency band to baseband, said signal comprising multiple...
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5566164 |
Practical means for digital generation and combination of a multiplicity of CDMA/FDMA signals
A modulator system for generating a plurality of individual modulated RF signals and combining them and transmitting them in different frequency channels. The invention provides a practical method...
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