erase head


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erase head

In a magnetic tape drive, the device that erases the tape before a new block of data is recorded.
References in periodicals archive ?
This VCR does not have a flying erase head. This figure is in Adobe Portable Document Format.
This VCR has a flying erase head. This figure is an XviD-encoded MPEG-4 video file with an .avi file suffix.
This VCR does not have a flying erase head. This figure is an XviD-encoded MPEG-4 video file.
When the overrecording VCR had a flying erase head, the beginning of the overrecorded portion, O, usually produced an uncorrupted frame transition from the underlying recorded portion, U, if both were recorded at the same speed (segments [O.sub.U] and [O.sub.P] are not present on units with a flying erase head).
The last segment of the overrecordings, [U.sub.N], had all of the video information from the underlying recording but had no control-track sync because it had been erased by the full-track erase head. This portion was exactly 79.244 mm in length at SP speed (79.253 mm at EP), based on the standardized distance between the end of the video heads and the linear audio record head (see Figure 3).
Unlike the video information recorded by VCRs without a flying erase head, there was no observed mix of the underlying and overrecorded hi-fi audio information in the [O.sub.U] segment.
The 80.00-mm erased segment, E, which is the pre-video erased area, has no video, hi-fi audio, linear audio, or control-track information because they were erased by the full-track erase head. This portion lasts 2.40 seconds (80.00/33.35).
The linear audio and control-track information are not present because they have been erased by the full-track erase head. If the audio and control data had been present, they would have been located 175.544 mm earlier on the tape (see Figure 5a).
The hi-fi audio information is present in this portion, but the linear audio and control-track information have been erased by the full-track erase head. Following this [U.sub.N] segment, the underlying recording, U, returns with the video, audio, and control-track information intact.
The distance from the full-track erase head to the video-recording head has been designated as 80.00 mm, the frame numbers have been rounded to the nearest whole number, all lengths are in mm, and all times are in seconds.
The second example is a 20.00-second overrecording with the following characteristics: (1) the underlying recording is at SP speed, (2) the overrecording is at EP speed, and (3) the underlying recording and overrecording VCRs have hi-fi audio heads, but the overrecording unit does not have a flying erase head. As listed in Table 3 and generically illustrated in Figure 5b, this overrecording configuration is divided into six segments:
Segment [O.sub.U] is the first part of the total overrecording and contains a mixture of both the underlying recording and overrecording because there is no flying erase head. This section is 80.00 mm in length, based on the pre-video erased area between the full-track erase head and the beginning of the video-head recording.