TA1370FG Datasheet, PDF (40/42 Pages) Toshiba Semiconductor – SYNC Processor, Frequency Counter IC for TV Component Signals

Application Circuit 2 (How to measure H/V frequency)
TA1370FG
To measure H/V frequency of signal 2 (fH2: unknown) correctly, use two separated input terminals as the
following figure. One is for frequency measuring (SYNC2-in) and the other is for the AFC (SYNC1-IN). And
measure H/V frequency of signal 2 (fH2: unknown) on condition that AFC is stable (AFC locks in signal 1 (fH1:
known).) or that AFC is free-run when SYNC1-IN is no-signal.
Signal 1
(fH1: known)
Signal 2
(fH2: unknown)
SYNC1-IN
for H-AFC
Signal 1
AFC
BUS READ
SYNC2-IN
for
H/V freq. counter
TA1370FG
Internal pulse (A)
Signal 2
H/V FREQ
COUNTER
This IC’s H/V frequency counting is done by internal pulse (A) which is made in AFC circuit. So, if AFC circuit
doesn’t lock in the regular frequency, the frequency of pulse (A) will not be correct and the H/V frequency data will
not be showed correct data.
Decision algorithm of H/V frequency detection (detection range, detection times and so on) should be determined
under consideration the factors such as signal strength, existence of ghost signal, H-AFC stability, I²C BUS data
transmission and so on via prototype TV set evaluation.
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2003-02-19