Icom IC-701

scan signal from the ACC socket (if used) is fed to Pin 9 and
the output signal is fed to Pin 4 of IC4. This is controlled
by the band edge detection signal, fed to Pin 1, and is sent
to the LSI in the PLL unit as the Clock (CK) signal. Pin 1
of IC3 is connected to Pin 11 and the delay circuits of R13
and C3 are connected with the data input Pin 9. 1C3 isaD
type flip-flop, so it latches the signal of the delay circuit.
1C3 gives a High (H) level signal when the tuning knob is
turned clockwise, and a Low (L) level signal when the knob
is turned counter-clockwise. This (H) or (L) signal goes to
Pin 13 of {C2 along with the signal from the ACC socket
(if used), which is fed to Pin 12. The output of IC2 is
added to the LSI as the UP/DOWN (UD) signal. .
PHOTO-CHOPPER CIRCUIT SCHEMATIC DIAGRAM
When the tuning knob is turned
counter-clockwise
TIMING CHART
Dr
PLENUNTNL
AUR FLE
HATE
Ae
TIMING CHART
SCAN
When the tuning knob is turned
clockwise
Nell
HAGE
: THAT bE i
Pela aes