AN INFINITELY CLIPPING SYSTEM FOR DIGITAL SPEECH TRANSMISSION,
Abstract
A digital speech transmission system is described in which the speech signal undergoes infinite clipping. The speech is first translated into the octave band 3-6 Kc/s before being infinitely clipped. It is then time-quantised at 15 Kb/s. An envelope signal is at the same time derived from the input speech, and this is converted to a digital signal at 5 Kb/s using a deltamodulator. The 15 Kb/s and 5 Kb/s digital signals are time division multiplexed to give an overall transmission rate of 20 Kb/s. The use of infinite clipping on the 15 Kb/s channel and a high ratio of bit rate/signal bandwidth on the 5 Kb/s channel has enabled a system to be produced which has a large dynamic range and at the same time an acceptable speech quality. No information specifically for synchronising is transmitted by the sender. A method of channel synchronisation has been evolved which depends upon the difference in the power spectra of the two channels. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1967
- Accession Number
- AD0675266
Entities
People
- F. W. Abbatt