Figure 4: A portion of the control track from Figure 2, which has been aligned with the rectangular signal that produced it.
If the overrecording is not long enough for the control-track record head to have reached the fully erased portion, then a segment of the underlying control-track information will follow the end of the newly written control track.
These figures show the narrow linear audio track at the top, the wide helical-scan video and hi-fi audio tracks in the middle, and the narrow control track at the bottom (only the positive sync pulses are displayed).
The control track is present during this portion, and so are the linear audio and hi-fi audio.
The first U segment is the return of the underlying recording for 13.30 mm, or 0.40 second (13.30/33.35), with the control track, the linear audio, and the hi-fi audio present.