Patent
Data transmission systems
William Hodgkiss
- 13 Mar 1987
87
TL;DR: In this paper, a modem for a digital data transmission system in which binary-coded data at up to 9.6 Kbit/sec is transmitted over a telephone line pair circuit, as phase and amplitude modulation (QAM) of a carrier signal at a frequency of 1800 Hz, at a line symbol rate of 2400 bauds.
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Abstract: A modem for a digital data transmission system in which binary-coded data at up to 9.6 Kbit/sec is transmitted over a telephone line pair circuit, as phase and amplitude modulation (QAM) of a carrier signal at a frequency of 1800 Hz, at a line symbol rate of 2400 bauds. The modem utilizes two data signal processors (4 and 5) and two gate arrays (6 and 7), controlled by a microprocessor (8), to carry out digitally all the processes required to convert binary coded data signals into PCM coded samples of the required carrier signal for transmission and to recover binary coded data signals from PCM coded samples of a received carrier signal.
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Citations
Patent
Computer-based multifunction personal communications system.
Raghu Sharma,Jeffrey P. Davis,Timothy D. Gunn,Ping Li,Sidhartha Maitra,Ashish Thanawala,Steve Young +6 more
- 23 Dec 1993
TL;DR: In this article, a personal communications system is described which includes components of software and hardware operating in conjunction with a personal computer, which includes telephone communication equipment, digital signal processors, and hardware to enable voice, fax and data communication with a remote site connected through a standard telephone line.
263
Patent
Trellis coded modulation for transmission over fading mobile satellite channel
Marvin K. Simon,Dariush Divasalar +1 more
- 15 Sep 1988
TL;DR: In this article, the combination of trellis coding and MPSK signaling with asymmetry (nonuniform spacing) to the signal set is disclosed with regard to its suitability for a fading mobile satellite communication channel.
Patent
Dynamic selection of compression rate for a voice compression algorithm in a voice over data modem
Raghu Sharma,Jeffrey P. Davis,Timothy D. Gunn,Ping Li,Sidhartha Maitra,Ashish Thanawala +5 more
- 29 Nov 1994
TL;DR: In this article, a negotiation handshake protocol is described which enables the two sites to negotiate the compression rate based on such factors, such as the speed or data bandwidth on the communications connection between two sites, the data demand between the sites and amount of silence detected in the speech signal.
140
Patent
Voice over data modem with selectable voice compression
Ping Li,Timothy D. Gunn,Jeffrey P. Davis +2 more
- 19 Jun 1995
TL;DR: In this paper, a personal communications system enables the operator to simultaneously transmit voice and data communication to a remote site, using a modified supervisory packet for negotiating communication parameters, including speech compression algorithm, the speech compression ratio, the communication multiplex scheme, and other operations needed for control of remote hardware interfaces.
121
Patent
Method and apparatus for wideband transmission of digital signals between, for example, a telephone central office and customer premises
Richard D. Gitlin,Sailesh Krishna Rao,Jean-Jacques Werner,Nicholas Zervos +3 more
- 16 Mar 1989
TL;DR: In this article, a telephone local loop transmission arrangement is presented, where data is communicated from the customer premises to the central office utilizing a multi-dimensional, passband signal illustratively at 480 kb/s and 1.544 Mb/s.
116
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Eric Paneth,Mark J Handzel,Steven Allan Morley,Graham M Avis +3 more
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TL;DR: In this article, a system and method for wireless communication between a plurality of subscriber units and a base station, the base station communicating information signals from an originating source to a destination subscriber unit over a channel at an assigned one of a plurality OF frequencies using repetitive time frames, each said time frame comprising a sequence of time slots.
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Kah-Seng Chung,Hendrikus Leonardus Verstappen +1 more
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TL;DR: In this article, an analog angle modulated carrier signal of a substantially constant amplitude was generated for data signals having a sum-bol rate 1 fT by using read-only memory for storing modulation parameters, addressing circuit for producing read addresses with a rate q/T, where q is an integer greater than 1.
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Patent
Constrained adaptive equalizer
John A. C. Bingham,Jack H. Kurzweil +1 more
- 03 Jun 1982
TL;DR: In this article, a constrained adaptive equalizer (10) is proposed for a digital communication system receiver combining transversal and decision feedback equalization techniques, which can be used for either passband or baseband equalization and for either complex signals, such as CAM signals, or real signals such as baseband single side band signal.
65
Patent
QAM modulator circuit
Charles A. Backof,Mark E. Huntzinger +1 more
- 20 Oct 1983
TL;DR: In this article, a method and means for quadrature amplitude modulation (QAM) is described, which utilizes a small read only memory to hold multiple versions of a signal constellation resulting in the elimination of hardware modulator circuits.
61
Microprocessor Implementation of High-Speed Data Modems
TL;DR: This paper describes the application of a commercially available microprocessor to a flexible data transmitter and data receiver for high-speed data modems.
60
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