| 摘要 |
When the relative speed of the head wheel to the tape transport is reduced for recording at a lower data rate, a resistance interposed between the stationary driver amplifier and the stator of a rotary transformer is reduced to produce a mismatch of the coupling between the driver amplifier and a recording amplifier on the head wheel. The latter is connected to the recording head. The mismatch lowers the upper cut-off frequency of transmission through the rotary transformer and shifts the frequency transmission band downward also lowering the lower cut-off frequency. A servo control which sets the relative speed of the head wheel circumference with reference to the moving tape provides a signal to a logic circuit which progressively switches in shunting resistors lowering the resistance interposed between the driver amplifier and the transformer stator, as the relative speed of rotary recording head to tape is reduced, for advantageous operation when the data rate is below the maximum data rate that can be used with the equipment. With a balanced circuit of the driver amplifier, an interposed resistance is connected on each side of the transformer stator and each of them is progressively shunted down by switching steps as the relative speed is reduced. At the highest relative speed, the output of the driver amplifier is matched to the input of the recording amplifier for good power transfer.
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