Adaptive transmit pre-emphasis for digital modem computed from noise spectrum
It is therefore the object of this invention to provide a method and apparatus for automated transmit pre-emphasis calculation which properly accounts for frequency-dependent signal-to-noise ratios. T... Read More
Inventors: Betts, William L.; DesRosiers, James J.;, Assignee: A.T. & T. Paradyne (Largo, FL) |
Method of transmitting a sequence of M binary words of "p" bits and transmission arrangement implementing this method
It is an object of the present invention to provide a method of the type mentioned in the preamble and which avoids this inconvenience. For this reason, such a method is characterized in that at least... Read More
Inventors: Bellon, Gilles;, Assignee: U.S. Philips Corporation (New York, NY) |
Apparatus for adjusting signal points, equalizer coefficients and the like
What is claimed is: 1. Apparatus for receiving a communication signal communicated over a communication medium, the communication signal modulated to include digital data in the form of a train of sym... Read More
Inventors: Viviano, Jerome J.; Raynor, Teri C.;, Assignee: Universal Data Systems, Inc. (Huntsville, AL) |
Quantizing and decoding of phase-amplitude modulated signals in hexagonal code
OF PREFERRED EMBODIMENTS In preferred phase-amplitude modulation, symbols for transmission are chosen from a hexagonal close packed (HCP) phase-amplitude constellation, e.g., as illustrated by the 16... Read More
Inventors: Reeves, Philip J.; Wougk, Harald A.;, Assignee: Mikros Systems Corporation (Princeton, NJ) |
Carrier synchronizing unit
It is an object of the present invention to provide a novel carrier synchronizing unit for a coherent detection data communication system over non-frequency selective fading channels wherein the redun... Read More
Inventors: Dobrica, Vasic;, Assignee: NEC Corporation (Tokyo, JP) |
Adaptive channel tracking using pilot sequences
In light of the above discussion, it is an object of the present invention to provide channel tracking which compensates for variations in the channel including channel fade. These and other objects o... Read More
Inventors: Arslan, Huseyin; Ramesh, Rajaram;, Assignee: Ericsson Inc. (Research Triangle Park, NC) |
Trellis decoder and associated method
Accordingly, an object of the present invention is to provide a trellis decoder and its associated method capable of accomplishing reductions in the circuit scale. In order to achieve the object, in a... Read More
Inventors: Fukuda, Kengo;, Assignee: Matsushita Electric Industrial Co., Ltd. (Osaka, JP) |
Trellis coded modulation system employing a flexible trellis coded modulation decoder
The present invention provides for a trellis coded modulation system for use with a plurality of QAM modes, including but not limited to, 16QAM, 64QAM, and 256QAM. The present invention allows a choic... Read More
Inventors: Swenson, Norman L.; Smith, Francis J.; Wolcott, Theodore J.;, Assignee: Lockheed Martin Corp. (Bethesda, MD) |
Methods and apparatus for efficient and accurate coarse timing synchronization in burst demodulators
The present invention is applicable to a variety of burst detection applications. In an illustrative but not limiting embodiment, the Coarse Timing Synchronization block 1550 of the present invention... Read More
Inventors: Boutros, Joseph; Lemois, Emmanuel;, Assignee: Juniper Networks, Inc. (Sunnyvale, CA) |
Production interface for integrated circuit test system
OF THE INVENTION FIG. 2 is a detailed functional block diagram of the complete test system of the present invention. The system includes a PC workstation 2000, tester 2002, a handler 2004, and a host... Read More
Inventors: Proskauer, Daniel C.;, Assignee: Teradyne, Inc. (Boston, MA) |
Cache and caching method for conventional decoders
OF THE PREFERRED EMBODIMENT A method and cache for caching encoded symbols for a convolutional decoder with forward and backward recursion includes storing different encoded symbols of an encoded fra... Read More
Inventors: Koehler, Kevin P.; Schaffner, Terry Michael;, Assignee: Motorola, Inc. (Schaumburg, IL) |
Sliding window technique for map decoders
OF THE PREFERRED EMBODIMENTS A. Example Environments A block diagram of one implementation a MAP decoder 115 is illustrated in FIG. 1. In this particular implementation, the decoder is a four port de... Read More
Inventors: Eidson, Donald Brian;, Assignee: Conexant Systems, Inc. (Newport Beach, CA) |
Sliding window turbo decoder
OF THE PREFERRED EMBODIMENT The present invention improves the sliding window technique of turbo decoding by shrinking successive learning periods needed for reliable computation as iteration proceed... Read More
Inventors: Xu, Shuzhan J.;, Assignee: Motorola, Inc. (Schaumburg, IL) |
Communication system transmitting encoded signal using block lengths with multiple integral relationship
According to the system of U.S. Pat. No. 5,907,563, if the transmission channel conditions change from the former to the later conditions during data communication, then the transmitter will change bl... Read More
Inventors: Morelos-Zaragoza, Robert; Swarts, Francis;, Assignee: Sony Corporation (Tokyo, JP) |
Digital FM demodulator with a reduced sampling rate
Notwithstanding these teachings of the prior art, the applicant has discovered that a modulated signal, such as, for example, an angle modulated signal such as an FM signal, contained substantially wi... Read More
Inventors: Solomon, James D.;, Assignee: Motorola, Inc. (Schaumburg, IL) |
Asynchronous sampling digital detector system for magnetic and optical recording channels
This invention is an Asynchronous Sampling Digital Detector (ASDD) signal processing technique that is entirely digital. It is applicable to recording channels and to other sampling systems. No analog... Read More
Inventors: Melas, Constantin M.; Sutardja, Pantas;, Assignee: International Business Machines Corporation (Armonk, NY) |
Method for processing sample values in an RLL channel
OF THE PRESENT INVENTION A method for processing sample values in an RLL channel is described. In the following description, numerous specific details are described in order to provide a more thoroug... Read More
Inventors: Pan, Tzu-Wang; Yamasaki, Richard G.;, Assignee: Silicon Systems, Inc. (Tustin, CA) |
Noise minimization for magnetic data storage drives using oversampling techniques
The invention provides an improved technique for minimizing the effects of noise sources in the environment of a data storage drive through the use of an oversampling process. The main objective of th... Read More
Inventors: Ottesen, Hal H.; Smith, Gordon J.;, Assignee: International Business Machines Corporation (Armonk, NY) |
Clock recovery circuit for extracting clock information from a received baseband signal
It is therefore an object of the present invention to provide a low-cost clock recovery circuit with simplified digital circuitry. The clock recovery circuit of the present invention comprises an asyn... Read More
Inventors: Iwasaki, Motoya;, Assignee: NEC Corporation (Tokyo, JP) |
Disk drive method using zoned data recording and PRML sampling data detection with digital adaptive equalization
A general object of the present invention is to provide an improved, high performance, high capacity miniature disk drive electrical architecture employing a PR4,ML data channel. A general object of t... Read More
Inventors: Abbott, William L.; Nguyen, Hung C.; Johnson, Kenneth E.;, Assignee: Quantum Corp. (Milpitas, CA) |
Data detecting apparatus using an over sampling and an interpolation means
It is therefore an object of the present invention to provide a data detecting apparatus which detects reproduced signal data without being affected by jitters contained in a reproduced signal coming ... Read More
Inventors: Yada, Hiroaki;, Assignee: Sony Corporation (Tokyo, JP) |
Clock reproducing apparatus and data reproducing apparatus utilizing weighting-adding of samples
With the above-mentioned drawbacks in view, an object of this invention is to provide a clock reproducing apparatus and a data reproducing apparatus which permit the circuit to be compact and adjustme... Read More
Inventors: Yada, Hiroaki;, Assignee: Sony Corporation (JP) |
Timing recovery frequency error detector for sampled amplitude magnetic recording
The objects of the present invention are achieved by utilizing an improved method and circuit for implementing timing recovery in a synchronous read channel. A digital phase-locked loop (PLL), compris... Read More
Inventors: Bliss, William G.;, Assignee: Cirrus Logic, Inc. (Fremont, CA) |
Sampled amplitude read channel employing interpolated timing recovery
The objects of the present invention are achieved by incorporating into a sampled amplitude read channel for magnetic recording an interpolating timing recovery loop rather than a sampling timing reco... Read More
Inventors: Spurbeck, Mark S.; Behrens, Richard T.; Feyh, German S.;, Assignee: Cirrus Logic, Inc. (Fremont, CA) |
Moderate rate phase shift keying codec
OF THE INVENTION FIG. 1 shows an example of a wireless communications system or network in which a number of subscriber stations, also referred to as remote terminals or user terminals, (symbolically... Read More
Inventors: Trott, Mitchell D.; Boros, Tibor;, Assignee: ArrayComm, Inc. (San Jose, CA) |
Data recording format for an information-bearing disk
OF A PREFERRED EMBODIMENT FIG. 2 illustrates an information-bearing disk 10 having a recording surface 12. Preferably, the recording surface 12 is optical, although various alternative surfaces, such... Read More
Inventors: Syracuse, Anthony A.;, Assignee: Eastman Kodak Company (Rochester, NY) |
Method and apparatus for processing sample values in a coded signal processing channel
The trend towards high density and high data rates presents heavy demands on the signal detection process in a magnetic recording channel. A peak-detection channel, with analog signal processing of on... Read More
Inventors: Patel, Arvind M.;, Assignee: International Business Machines Corporation (Armonk, NY) |
Clocking method and apparatus for use with partial response coded binary data
OF THE INVENTION The present invention will be described with reference to only one of the known partial response signaling techniques, namely Class IV partial response signaling. However, the scope ... Read More
Inventors: Cunningham, Earl A.; Porter, Jr., Townsend H.; Rae, James W.;, Assignee: International Business Machines Corporation (Armonk, NY) |
Correlation code transmission system
The object of this invention is to provide a transmission system which fixes the frame synchronization pattern on the transmission line and thereby makes the observation of the transmitted data easy. ... Read More
Inventors: Kazawa, Tohru; Miyamoto, Takanori; Suzuki, Toshiro; Morita, Takashi; Mass'e, Ichiro;, Assignee: Hitachi, Ltd. (Tokyo, JP) |
Timing loop method and apparatus for PRML data detection
OF THE PREFERRED EMBODIMENT In FIG. 1 there is shown a partly schematic block diagram of parts of a data storage disk file 10 including a data storage medium generally designated as 12 and an interfa... Read More
Inventors: Coker, Jonathan D.; Galbraith, Richard L.;, Assignee: International Business Machines Corporation (Armonk, NY) |
Fault Detection 
