|
Match
|
Document |
Document Title |
|
|
5867503 |
Digital sound broadcasting receiver and automatic phase controlling method therefor
A digital sound broadcasting receiver and method receives a radio wave from a digital sound broadcasting station, demodulates the radio wave into baseband signals at a tuner, subjects the signals...
|
|
|
5864550 |
Wireless local area network system and receiver for the same
The invention relates to a wireless local area network system having data terminals and transceivers which communicate with the data terminals and transmit and receive data, for forming a wireless...
|
|
|
5809069 |
Frequency-domain carrierless AM-PM demodulator
A frequency-domain CAP receiver is provided that reduces the number of operations required to demodulate a CAP signal. The frequency-domain CAP receiver provides computational advantages over an...
|
|
|
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,...
|
|
|
5771224 |
Orthogonal frequency division multiplexing transmission system and transmitter and receiver therefor
A transmission system is disclosed which permits the receiving end to demodulate multi-valued modulated symbols successfully under fading conditions and reduces the amount of transmitted reference...
|
|
|
5771263 |
Communication system control method and communication system using the method
A communication system having a carrier oscillator for generating a carrier of predetermined frequency, a quadrature modulator for orthogonally modulating the carrier by input baseband I and Q...
|
|
|
5673292 |
AM-PSK system for broadcasting a composite analog and digital signal using adaptive M-ary PSK modulation
A radio-frequency broadcasting system and method for simultaneously broadcasting analog and digital signals in a standard AM broadcasting channel wherein the system includes: a transmitter for...
|
|
|
5602868 |
Multiple-modulation communication system
A multiple-modulation communication system includes a transmitter that modulates and transmits communication signals modulated by a first modulation technique and communication signals modulated by...
|
|
|
5598435 |
Digital modulation using QAM with multiple signal point constellations not equal to a power of two
Data are transmitted using multiple carriers modulated by quadrature amplitude modulation. In general, the carriers carry different numbers of bits, to exploit the fact that the properties of a...
|
|
|
5440543 |
Duplex system using a single transmission line
A signal transmitter-receiver system comprising first and second transmitter-receiver units interconnected by a signal transmission line, a first transmitter-receiver unit including a first...
|
|
|
5430711 |
Group modulator
A group modulator provided a plurality of digitally modulated signals with frequency division multiplex, having a time division multiplexer (11) for multiplexing a plurality of input data (#l...
|
|
|
5367536 |
Parallel transmission of TDMA sync and data bursts by artificial frequency selective fade and decision feedback equalization
A data burst is modulated on an IF carrier, and a spectral null is artificially created in the center frequency region of the spectrum of the modulated data burst by taking the difference between...
|
|
|
5349608 |
Viterbi ACS unit with renormalization
In a Viterbi decoder including an add-compare-select (ACS) processor, speed is enhanced without loss of performance by maintaining a dynamic cumulative metric range for computed state metrics....
|
|
|
5187719 |
Method and apparatus for measuring modulation accuracy
A method and apparatus for determining the phase and amplitude accuracy of continuous-phase-modulated signals is described. A modulated RF signal generated by a transmitter is down converted to a...
|
|
|
5113412 |
Method and apparatus for mapping an eight dimensional constellation of a convolutionally coded communication system
A mapping technique for an 8D, sixty-four state convolutionally coded 19.2 Kbit/second modem utilizes twenty-nine bits for defining all points of an 8D constellation. The 8D constellation which is...
|
|
|
5088111 |
Modulation and demodulation system employing AM-PSK and FSK for communication system using digital signals
A communication network having a first broadband communications channel or transmitting bus and a second broadband communications channel or receiving bus, wherein the first broadband...
|
|
|
5081649 |
Method of quadrature-phase amplitude modulation
A rectangular array of signal points forming a QAM signal point constellation is modified by relocating signal points from adjacent corners of the rectangular array to positions extrapolated from...
|
|
|
5058134 |
Process of synchronizing a receiving modem after a training on data
In data transmission wherein a transmitting modem transmits data signals to a receiving modem via a telephone line, the process of rotating, in the transmitting modem, the phase of the point of the...
|
|
|
5058135 |
Modulating arrangement for phase and amplitude modulation of a wave
An arrangement by which a sinusoidal wave is modulated in phase and amplitude in response to groups of bits includes an input (1) for receiving the groups of bits, a phase shifting circuit (5, 7)...
|
|
|
4959842 |
Signal constellations
A Voronoi signal constellation with ties includes those points of a lattice Λ (or a coset Λ+c) that lie within a Voronoi region of a sublattice Λ' of Λ, Λ' being other then a scaled version of...
|
|
|
4943980 |
Multi-carrier high speed modem
A modem system includes a transmitter section having generators for successively generating sets of carrier signals where each carrier signal of a set has a different frequency and a modulator for...
|
|
|
4907218 |
Multiplex signal processing apparatus
In a multiplex signal processing apparatus, in the band of a demodulated signal in which a carrier is amplitude-modulated in a vestigial side band by a main signal, another carrier is superposed...
|
|
|
RE33056 |
Signal structures for double side band-quadrature carrier modulation
Double side band-quadrature carrier modulation signal points as mapped on the complex plane are drawn from an alphabet consisting of at least 8 points, and are set up in concentric rings each...
|
|
|
RE33041 |
Multi-dimensional coding for error reduction
A stream of binary bits is converted into blocks of eight parallel bits. A first group of five of the eight bits addresses a memory device which has thirty-two code words each having four numbers...
|
|
|
4843613 |
Digitally implemented modulators
A digitally implemented modulator for generating samples of a band-limited modulated output signal from an inputted binary data signal made up of a train of sets of data bits. Samples values are...
|
|
|
4841571 |
Privacy signal transmission system
A privacy signal transmission system having a transmitter portion and a receiver portion. The transmitter portion digitizes an analog message signal and enciphers the digitized signal into a...
|
|
|
4794341 |
Digital filters and demodulators
A filter, in which digital representations of a signal are stored as samples in a store (8) preferably in the order of their occurrence. Multipliers (9) multiply the samples by coefficients (C1 to...
|
|
|
4788696 |
Decision timing control circuit
A circuit is provided for controlling the decision timing of an A/D converter so that error rate becomes small. Error rate information is obtained based on the converted digital signal from the A/D...
|
|
|
4748641 |
Suppressed carrier modulation method
A carrier is modulated with binary coded data to produce a suppressed carrier constant amplitude wave by shaping modulation for the carrier so the carrier phase changes gradually between...
|
|
|
4748640 |
Digital circuit with band limiting characteristics for modem
The input digital signal is applied to a transition detector which causes an up/down counter to increment or decrement each time a transition is detected. The output of the counter is utilized to...
|
|
|
4745625 |
Transition detector
The unknown time when a transition in a signal point sequence has occurred is determined by a trellis technique based on known subsequences of symbols that preceded and followed the transition.
|
|
|
4691318 |
Data transmission system with error correcting data encoding
A multiphase communication system for simultaneously transmitting plural binary digits employs one or more error-check bits which perform an encoding on the conveyed information over a plurality of...
|
|
|
4677627 |
Error correction scheme
An error correcting scheme for processing data which is transmitted on a broadband and/or CATV network and utilizes the IEEE 802.4 three-level duobinary AM/PSK (phase shift keying) coding format....
|
|
|
4675619 |
Multiple quadrature-phase amplitude modulating system capable of reducing a peak amplitude
In a multiple QAM system in which a pair of quadrature-phase carrier signals is modulated by a first and a second input digital signal, each representative of N or less levels, into a...
|
|
|
4660213 |
Signal structure for data communication
A signal structure for high speed data communication selects each signal point in the structure to attain a low probability of error in the presence of both additive noise and multiplicative noise....
|
|
|
4597090 |
Block coded modulation system
An improvement to a modulation system of the kind in which the encoder selects a codeword corresponding to a plurality of modulation signal points on the basis of a block of digital data, the...
|
|
|
4592071 |
Recovery of carrier and clock frequencies in a phase or amplitude state modulation and coherent demodulation digital transmission system
This invention aims at making a carrier wave synchronous with a clock signal provided with a digital signal in a modem transmitting part and at recovering a carrier wave having a phase coherent...
|
|
|
4584541 |
Digital modulator with variations of phase and amplitude modulation
A phase modulator includes a digital frequency word generator, an adder and a register arranged to generate recurrent digital sawtooth signals at a carrier rate. A second digital adder is coupled...
|
|
|
4581748 |
QAM with DC bias in one channel
A radio communication system includes a transmitter unit, a transmission line, and a receiver unit. The transmitter unit modulates an in-phase-channel (I-ch) data signal and quadrature-channel...
|
|
|
4580276 |
System and method for transporting data
A private local area network (LAN) is created for use with a variety of transmission media for the purpose of exchanging data preassigned addresses, and control signals according to simplified...
|
|
|
4564823 |
Fractional-cycle time/amplitude modulation
A modulation system wherein a carrier signal is modulated by an input signal having a variable amplitude, either analog or digital. The amplitude of the input signal is sampled every predetermined...
|
|
|
4546322 |
Adaptable demodulator for arbitrary amplitude and phase keyed modulation signals
A demodulator for demodulating a received signal which has been modulated in accordance with a modulation scheme which falls within the class of APK modulation. The demodulator uses a phase locked...
|
|
|
4538284 |
Signal structures with data encoding/decoding for QCM modulations
Locations of a desired number of signal points for a double side band-quadrature carrier modulation system occupy the inner intersections of a multiplicity of concentric rings with a triangular...
|
|
|
4538111 |
Circuit recovering the carrier of a signal amplitude and phase modulated by digital signals
An apparatus for the recovery of an amplitude-modulated and phase-modulated signal wherein the signal is multiplied by two correction and adjustment signals in phase-quadrature in a pair of...
|
|
|
4529950 |
Digital phase and amplitude modulator
A digital phase and amplitude modulator with a code conversion circuit having several digital inputs able to receive digital data and the same number of outputs supplying code converted digital...
|
|
|
4516087 |
Method for reducing side-lobe energy in an MSK detectable signal
A method and apparatus for generating an MSK detectable signal with reduced side lobe energy of the type in which the MSK detectable signal has two combined orthogonal channels to transmit a data...
|
|
|
4509171 |
Modem multiplexer synchronization by radial modulation
This invention provides a digital data communication system which is able to combine two data streams from two data sources at the transmitter end, transmit the data and then separate the streams...
|
|
|
4495477 |
Multiple amplitude and phase shift keyed signal modulation method
In a multi-phase modulation method in which digital words each having a word length of at least 3 bits control the generation of a modulated carrier in a manner such that each digital word value is...
|
|
|
4457004 |
Multidimensional channel coding
An n-dimensional channel code is used in a data transmission system. The alphabet of codewords (data symbols) comprises a subset of points of a selected coset of a selected lattice. The alphabet...
|
|
|
4447908 |
Method of transmitting binary data sequences and arrangement for enabling the rapid determination of the end of a transmitted binary data sequence
A communication method and arrangement are disclosed which provide, for a trellis encoding process in the transmitter and a maximum-likelihood decoding process in the receiver, an additional fifth...
|