| 摘要 |
<p>SIGNAL DETECTION DURING VARIABLE SPEED TAPE MOVEMENTS A signal detection arrangement is disclosed for detecting signals during variable speed tape movements such as during tape rewinding or fast forward speeds. To elaborate, information encoded as multifrequency information tones is grouped in exercises on a recording tape, and at least two low frequency tones are provided at the beginning of each exercise. Each of these low frequency tones has a frequency which is related to the frequency of a different one of the information tones by a multiple of the ratio of the rewind speed to the normal forward speed times a predetermined factor. Accordingly, during normal playback these low frequency tones will not be detected. However, during fast forward or rewind, each of these tones will be multiplied up to a detectable frequency. Moreover, even over wide variations in these "fast" speeds, at least one of these low frequency tones will be detected.</p> |
