Kenwood TS-820 Operating Manual page 30

standard oscillator t o produce a voltage to control VCO (vol-
C O U N T E R A S S ' Y
U N I T (OPTION) I X 6 0 - 1 0 2 0 - 0 0 )
tage controlled oscillator). It also forms a full electronic IF
s h ~ f t loop using an external carrier signal. The VCO unit is
.
composed of FET type osc~llators for each band. buffer am-
p l ~ f ~ e r circuit. and the oscillator shut off circuit at the time of
fault of the PLL circuit. The oscillator frequency is controlled
i
by the control voltage from the PD Board. The bands of
both units can be selected b y means of the diode sw~tches.
Counter Ass'y Unit
This unit is composed of the counter mixer board that
produces
operating
frequencies by mixing the VCO output
(local oscillator stgnal for the mixer) with carrler signal, and
the counter board that counts the frequencies
in
d~gits.
These units are housed in a r ~ g i d shielding case. Since the
frequencies are read by synthesizing all the local oscillator
stgnals, accurate operating frequencies are always counted
under any operating conditions. The counter output is pick-
ed up as a signal to d r ~ v e the indicating tubes and is fed to
the d~splay unit.