Optimum Use of One-Inch Type C Audio Channels

Author(s): Martin A. Lilley
Publisher: Society of Motion Picture and Television Engineers
Publication Date: 1 February 1982
Conference Location: Nashville, TN, USA
Conference Date: 5 February 1982
Page(s): 82 - 90
ISBN (Paper): 978-1-61482-912-6
DOI: 10.5594/M00625



Although the audio tracks on the SMPTE and EBU Type C formats are only .031 inches wide compared with .070 inches wide on the 2-inch quadruplex format the audio performance of Type C format video tape recorders exceeds that of quadruplex machines. At first it would appear that the narrower track width used on the Type C format would result in an audio signal-to-noise ratio inferior to that obtained on quadruplex recorders, but this is not the case. Because the video tracks are slanted at an acute angle along the tape, the magnetic particle orientation of one-inch videotape is made longitudinal to favor the video performance. This proves of considerable benefit as far as the audio performance is concerned. The use of narrow audio tracks allows three or four (EBU format C option III) high quality audio channels to be recorded on one- inch wide videotape. This permits greater flexibility of operation and cuts down on capital equipment costs for such items as separate open reel audio recorders and machine synchronizers which would otherwise be required.