Magnetic recording and reproducing system

Claim 1

A magnetic recording and reproducing system comprising a first video signal processing means (l2) for subjecting an input video signal in conformance with a standard television system to a predetermined signal processing and for producing a video information signal having a predetermined signal format suited for magnetic tape recording and reproduction; first recording and reproducing means (l5a, l5b) for recording and reproducing the video information signal on and from tracks formed obliquely to a longitudinal direction of a magnetic tape (33); second video signal processing means (37) for subjecting the video information signal reproduced by said first recording and reproducing means to a predetermined signal processing and for producing a reproduced video signal in conformance with said standard television system; analog-to-digital converting means (22a, 22b, 23a, 23b) for sampling an input analog audio signal at a predetermined sampling frequency and for producing a digitized audio signal; encoding means (26) for encoding said digitized audio signal from said analog-to-digital converting means into an encoded digital audio signal; second recording and reproducing means (3la, 3lb) for recording and reproducing the encoded digital audio signal on and from the tracks of the magnetic tape, each of said tracks being recorded with the video information signal and the encoded digital audio signal respectively amounting to one field of said input video signal; decoding means (43) for decoding the encoded digital audio signal reproduced by said second recording and reproducing means; and audio signal producing means (43, 47a, 47b) comprising means for producing a reproduced digitized audio signal from the samples obtained from said decoding means and means for producing a reproduced analog audio signal by subjecting the reproduced digitized audio signal to a digital-to-analog conversion, characterized in that said encoding means (26) encodes said digitized audio signal from said analog-to-digital converting means (22a, 22b, 23a, 23b) into an encoded digital audio signal comprising first and second blocks which occur in a predetermined sequence dependent on a field frequency of the input video signal and an identification signal for identifying said first and second blocks, said first block being made up of a first number of samples constituting said digitized audio signal from said analog-to-digital converting means, said second block being made up of a second number of the samples constituting said digitized audio signal from said analog-to-digital converting means, said first and second number of samples respectively being greater than and less than a number of samples in l/N frame of said input video signal, where N is an integral multiple of five when the field frequency of said input video signal is approximately 60 Hz and is an integral multiple of six when the field frequency of said input video signal is 50 Hz, said encoding means successively encodes all of the samples constituting said digitized audio signal from said analog-to-digital converting means in each frame so that codes are completed in each of said first and second blocks, and said decoding means (43) decodes the reproduced encoded digital audio signal from said second recording and reproducing means (3la, 3lb) in blocks with reference to the identification signal so as to produce all of the samples of each frame.