Azimuth recording is the use of a variation in angle between two recording heads that are recording data so close together on magnetic tape that crosstalk] would otherwise likely occur. Normally, the head is perpendicular to the movement of the tape, and this is considered zero degrees. However, if the heads are mounted at slightly different angles (such as + or - 7 degrees in VHS), destructive interference will occur at high frequencies when reading data recorded in the cross-talking channel but not in the channel that is intended to be read. At low frequencies relative to the maximum allowed by the head gap, however, this technique is ineffective. In telecommunication, the term crosstalk (XT) has the following meanings: 1. ... Top view VHS cassette with US Quarter for scale Bottom view of VHS cassette with magnetic tape exposed The Video Home System, better known by its acronym VHS, is a recording and playing standard for video cassette recorders (VCRs), developed by JVC (with some of its critical technology under lucrative...
In order to further increase the recording density, many commercialized models have a "triple" recording mode in which the tape is recorded and reproduced at a speed 1/3 the standard tape speed so as to achieve the recording period three times as long as that in the normal operation mode using the same tape.
There has been proposed a method of tape recording and reproduction at a low tape speed, in which the audio signal is frequency modulated, for example, and recorded on a multiplex basis with the video signal by employment of rotary magnetic heads which provide a sufficient relative speed between each head and the recording medium.
Generally, the azimuth loss L is expressed in terms of the width of overlapping portion of the track W, the recording wavelength.lambda., the azimuth angle of the video head.theta..sub.1, and the azimuth angle of the audio head.theta..sub.2, as follows.
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