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(3) Local Synthesizer Circuit
The output of 14MHz OCXO(Over Compensated
X-tal Oscillator) is a standard frequency and PLL
IC(IC54), VCO(VCO1), DDS(IC56) is output as 1'st
LOCAL input signal 49.455~79.4549MHz and 7MHz
from output of DDS (IC60) makes 49MHz in 7
frequency multiplier circuit and use as 2'nd LOCAL.
3'rd LOCAL (BFO, Beat Frequency Oscillator) makes
456.4kHz_125Hz signal directly from DDS (IC62).
(4) Power Supply Circuit
Power circuit consists of control circuit of power
unit to turn on/off DC-24V in power amplifiable unit,
constant voltage circuit to supply DC voltage to be
constant voltage in each unit. AUDIO AMP for
external speaker and operate through DC INPUT
(24V BATTERY).
①
Main Power Circuit and Power Control Circuit
When switch on
, it controls Relay & goes
through Line Filter to supply the power. The output
power is +15V / +12V / +8V (voltage for printer) /
+7V (Voltage for LCD DIMMER) / +5V. In addition,
it supplies the voltage to NBDP terminal (SN-100),
ALARM BOX (SD-25), Printer (OKI or DPU-414).
②
Protection / Sensor Circuit
Operated to turn off the power automatically in a
condition of more than +31V or less than +19V
owing to built in a Power sensor circuit and it is
built in the circuit preventing conversing voltage to
avoid damage.
In addition, it is built in Current Sensor to protect
the power circuit and power amp with 0.0025
Ω
resistance.
