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US 4,307,946 AGranted
Flutter compensator with variable oscillator
AssigneePolaroid Corporation
InventorsWilliam R. Wray, James Burkhardt
Life of this patent
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AssigneePolaroid Corporation
InventorsWilliam R. Wray, James Burkhardt
Estimating the term…
Flutter in an audio signal recorded on a magnetic tape is reduced by sampling the audio at a rate determined by the frequency of a reference signal also recorded on the tape, reading the samples into respective cells of a memory, and reading out respective cells of the memory at a substantially constant rate that is independent of rapidly changing short duration variations in tape speed. The read-out rate is isolated from tape speed by introducing a time delay between the read-in and read-out of the same sample, the amount of the delay changing in accordance with differences in speed between the tape and a fixed reference. Changes in the delay between read-in and read-out of the same sample generate an error signal that is used to control the speed of the capstan motor that drives the tape past a transducer.
Apparatus for providing tape loop and flutter control in an audio-visual system having an information signal and a reference signal simultaneously recorded on an audio tape strip, said system having a transducer, a capstan, a motor for operating said capstan to advance said tape strip across said transducer and into a free loop, a loop sensor, a storage memory, means for reading in samples of the information signal to said memory at a first rate related to the frequency of the reproduced reference signal, means for reading out samples from said memory at a second rate to reproduce the recorded audio, and means for controlling the motor speed in accordance with the ratio of the read-out to read-in rate, the improvement comprising:
A method of providing tape loop and flutter control in an audio-visual system having an audio signal and a reference signal simultaneously recorded on an audio strip, the method comprising:
Dependencies are inferred from the claim text.