CCDs for Speech Bandwidth Reduction
Semi-annual technical rept. 18 Apr 1977-18 Oct 1978
TEXAS INSTRUMENTS INC DALLAS CENTRAL RESEARCH LABS
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This report concerns the progress to date in the development of analog CCD devices to be used in the implementation of a highly integrated, potentially low-cost version of the Belgard channel vocoder algorithm. This interim report will describe both the voice analyzer and synthesizer IC topologies, but will concentrate on the design details of only the analyzer IC which is nearing completion of the design phase. A simplified block diagram of the Belgard vocoder is shown in Figure 1. In the first demonstration the two portions of the system enclosed by dashed lines will be custom CCDMOS LSI circuits, one for speech analysis and one for speech synthesis, that are the subject of the current contract. The presampling and preemphasis filters are relatively simple analog filters that ultimately can be included in the analyzer IC. The pitch extraction, framing, and encoding will be implemented digitally using microcomputer. At the receiving end a microcomputer will decode the digital information and send twenty eight-bit digital words to the synthesizer IC per frame.
- Electrical and Electronic Equipment
- Computer Hardware
- Voice Communications