Panasonic KX-G8300 Service Manual And Technical Manual page 41

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5) Horizontal / Vertical Sync Pulse Generator
Circuit Operation:
The horizontal and vertical sync pulses are generated by the GDC and supplied to the CRT circuit.
W4ol
CRT
Circuit
Fig. 38
6) Alarm Circuit
Circuit Operation:
The alarm zone corresponding to the alarm zone setting is set in the programmable counter. The signal
indicating the alarm bearing zone is supplied from the CPU to the gate circuit.
When echo signals exist in the selected area, the output signal from the gate circuit (IC20, IC3) triggers
the one-shot circuit, and a pulse of approx. 0.5 sec is generated. The 2 kHz audible clock signal is gatec
in the gate circuit, and it drives the buzzer in the display unit. The amplifier consisting of Q4 (Q23, Q24)
serves to amplify the alarm signal supplied from the gate circuit and drive the optional externally con-
nected speaker.
VRM ; (ue
Bearing
CPU Programable Counter a ee
ek EBL1 EBL2
{C27 2kHz
+12V +12V 23V
Py
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(2) | ZZER-
lev
Ey ERNAL
x13 Si AKER VOLUME
v VRisi
& - @zs
\ 39 pa
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C46
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2m
Fig. 39