Proceedings ArticleDOI
Design of a Convolver-Based Packet Voice Spread Spectrum System
M. Kowatsch
- Vol. 15, Iss: 11, pp 127-131
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TLDR
A spread spectrum system for the transmission of packet voice has been developed and measures of performance being the probability of burst loss and the bit error probability in an additive white Gaussian noise channel are in good agreement with theoretical predictions.Abstract:
A spread spectrum system for the transmission of packet voice has been developed. Using a continuously variable slope delta (CVSD) modulator, speech signals are encoded at 16 kbit/s. The encoder output data stream is split into blocks of 1024 bits, which are t ransmitted in bursts at a data rate of 84 kbit/s. For data representation binary code shift keying (CSK) is employed. The spreading modulation is direct-sequence (DS) with a chip rate of 21.4 MHz. The receiver design is based on the application of two SAW elastic convolvers to programmable matched filtering of the continuously changing code patterns. The alignment of received signal and local reference is accomplished by means of an 11-bit preamble preceding each data packet. Experiments are in good agreement with theoretical predictions, measures of performance being the probability of burst loss and the bit error probability in an additive white Gaussian noise channel.read more
Citations
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Applications of surface acoustic and shallow bulk acoustic wave devices
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Convolver-Aided Synchronization in a Direct-Sequence Spread Spectrum Communication System
TL;DR: In the presented system convolvers with I6 integration time and an input 3-dB bandwidth of 90 MHz, centered at 300 MHe, correlate 800-chip PN code patterns and the resulting processing gain is 29 dB.
Proceedings ArticleDOI
Surface acoustic wave convolvers for spread-spectrum mobile and wireless communications
TL;DR: In this paper, surface acoustic wave (SAW) convolver types for use in real-time spread-spectrum code-division multiple access (CDMA) mobile and wireless communications in noisy electromagnetic environments.
Book ChapterDOI
Message protection by spread spectrum modulation in a packet voice radio link
TL;DR: The two most common forms of spread spectrum modulation are direct-sequence (DS) and frequency-hopping (FH), the first of which is considered in this paper.
References
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Proceedings ArticleDOI
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Delta Modulators in Packet Voice Networks
TL;DR: The performances of the SVADM and the CVSD in terms of dynamic range, sampling rate and the channel errors are compared and the parameters employed for subjective evaluation of the packet voice system are packet size, silence detection algorithm, bit rate and packet loss rate.
Proceedings ArticleDOI
Fast Synchronization in a Spread-Spectrum System Based on Acoustoelectric Convolvers
D. Brodtkorb,J.E. Laynor +1 more
TL;DR: A wideband PN spread-spectrum modem has been implemented using a pair of acoustoelectric convolvers as programmable matched filters in combination with digital delay and coincidence gating to achieve coarse synchronization to a precision of one PN chip using only four preamble bits.