Sound-in-Syncs
Sound-in-Syncs is a method of multiplexing sound and video signals into a channel designed to carry video, in which data representing the sound is inserted into the line synchronising pulse of an analogue TV waveform. This is used on point-to-point links within broadcasting networks, including studio-to-transmitter links. It is not used for broadcasts to the public.
History
The technique was first developed by the BBC in the late 1960s. In 1966, The corporation's Research Department made a feasibility study of the use of pulse-code modulation (PCM) for transmitting TV sound during the synchronising period of the video signal. This had two advantages: it removed the necessity for a separate sound link and offered improved sound quality and reliability.[1]
Awards
Sound-in-Syncs and its R&D engineers have won several awards, including:
- The Royal Television Society's Geoffrey Parr Award in 1972[2]
- A Queen's Award for Enterprise in 1974[3]
- In 1999, a Technology & Engineering Emmy Award[4]
Versions
Original mono SiS
In the original Sound-in-Syncs system, a single audio channel of about 14 kHz bandwidth was represented by 10-bit linear PCM with analogue companding.[1]
Ruggedised SiS
A ruggedised version of the system was developed, which provided about 7 kHz audio bandwidth, for use over noisy or difficult microwave paths, such as those often encountered for outside broadcasts. [5]
Stereo SiS
Later systems, developed in the 1980s, used 14-bit linear PCM samples, digitally companded into 10-bit samples by means of the NICAM lossy compression algorithm. These were capable of carrying two audio channels and were known as stereo sound-in-syncs.
Notes and references
- ^ a b Pawley, E (1972). BBC Engineering 1922-1972, pp. 506-7, 522. BBC. ISBN 0 563 12127 0.
- ^ BBC Research: RTS Awards
- ^ BBC Research: Queen's Awards
- ^ BBC Research: Emmy Award for Sound in Syncs
- ^ Dalton, C.J. (1971), A P.C.M. Sound-in-Syncs System for Outside Broadcasts, BBC Engineering, No. 86, April 1971, pp 18-28.
Further Reading
- Waveform Specification of the BBC Sound-in-Syncs Equipment, EBU Review, 121A, June 1970.
- Chorley, J.M. and Shorter, D.E.L. (1970), P.C.M. Sound-in-Syncs: Operational Systems for Video Distribution and Contribution Networks, IEE Conference Publication, No. 69, 1970 International Broadcasting Convention
- Dalton, C.J. (1968), The Distribution of Television Sound Signals by PCM Signals incorporated in the Vision Waveform, IEE International Broadcasting Convention, September 1968, Vol. 46, Part 1
- Sanders, J.R. (1967), Pulse sound: a system of television sound broadcasting using pulses in the video waveform, BBC Engineering Monograph, No. 67, May 1967
- Sanders, J.R. (1968) Pulse-code modulation for high-quality sound signal distribution: Incorporation of the sound signal in the video signal. BBC Research Department report (PDF)
- Shorter, D.E.L., Chew, J.R., Howarth, D. and Sanders, J.R. (1968), Pulse code modulation for high-quality sound signal distribution, BBC Engineering Monograph, No. 75, December 1968
- Shorter, D.E.L. (1969), The Distribution of Television Sound by Pulse-code Modulation Signals incorporated in the Video Waveform, EBU Review, No. 113A, February 1969