Appeal No. 1998-3409
Application No. 08/525,152
BACKGROUND
The appellant's invention relates to an automatic head switching control method and
apparatus for use in a VCR. An understanding of the invention can be derived from a
reading of exemplary claim 1, which is reproduced below.
1. An automatic head switching control apparatus for use in a VCR
having a drum driven by a drum motor, said drum having a plurality of heads,
the apparatus comprising:
a head switching signal generator for generating a head switching
signal according to drum phase generation (DPG) and drum frequency
generation (DFG) signals supplied from the drum, delay data, and a shift
command signal of a head switching point of time for each head;
a format detector coupled to an output end of the head switching
signal generator, for comparing the head switching signal with a vertical sync
signal of a video signal and detecting whether an interval of time between
both the head switching signal and the vertical sync signal meets a
predetermined range;
a controller for supplying the delay data and the shift command signal
of the head switching point of time for each head to the head switching
signal generator according to the output of the format detector;
a storage portion for storing the delay data generated when the
format detector judges that the format is met; and
a drum phase detector for detecting a drum phase according to a
drum reference signal output from a drum reference counter and the head
switching signal output from the head switching signal generator, and
supplying a drum phase control signal to the drum.
2
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