| 摘要 |
Magnetic head positioning and playback apparatus is provided for use with a helical scan tape recorder to accurately position a playback head with respect to a magnetic track. The playback head has a split face portion dividing the playback gap substantially in half. Reproduce signals from the corresponding portions are simultaneously processed to provide an indication of positional error and summed to provide a playback signal. In one form, by differencing the reproduce signals from the corresponding portions and by multiplying the difference and sum signals together, a usable correction signal is provided to a servo circuit for simultaneously centering the head on the track while reproducing a playback signal - this being accomplished without the use of a separate control track. By further comparing the correction signal with a reference level, momentary disturbances in the track are detected as they occur; this information is used to determine which portion of the head provided the disturbance and to prevent that portion's signal from summing into the playback signal.
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