US 4,902,946 AGranted

Software servo for a rotary head drum of VTR

AssigneeSony Corporation

InventorTadafusa Tomitaka

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Abstract

A servo circuit controls the rotation of a drum motor to rotate a rotary head drum having a frequency generating circuit for generating a frequency signal corresponding to the revolution speed of a drum motor, a cycle detector circuit detects a cycle of the frequency signal from the frequency generating circuit, and a detector circuit speed deviation between a detected signal from the detector circuit and a reference signal to produce a first circuit generates speed deviation signal, a first circuit for generating a first circuit generates first rotation control signal based on the speed deviation signal, and a second circuit produces a second rotation control signal based on phase difference data obtained by integrating the speed deviation signal. An adder circuit adds the first and second rotation control signals to produce a rotation control signal which is supplied to the drum motor to stably rotate the rotary head drum.

Claims8

Dependent claims

Apparatus for controlling a rotation of a drum motor to rotate a rotary head drum, said apparatus comprising:

a driver circuit and
a servo circuit;
said servo circuit comprising:
means for generating a frequency signal corresponding to a revolution speed of said drum motor;
means responsive to said frequency signal generating means for detecting a cycle of said frequency signal from said frequency signal generating means to produce a detected signal;
means for generating a reference speed signal;
means responsive to said detecting means and said reference speed signal generating means for detecting a speed deviation between said detected signal from said detecting means and said reference speed signal to produce a speed deviation signal;
means responsive to said speed deviation signal means for generating a speed control signal based on said speed deviation signal;
means responsive to said speed deviation signal means for effecting an integration of said speed deviation signal;
means responsive to said integration means for producing a phase control signal based on said integration of said speed deviation signal;
and
means responsive to said speed control signal means and said phase control signal means for adding said speed control signal and said phase control signal to produce a rotation control signal;
said rotation control signal being supplied to said driver circuit and said driver circuit driving said drum motor in response to said rotation control signal.

10 more elements

Dependencies are inferred from the claim text.