Marantz SR620 - Page 15

AM (MW/LW) OSC
0.01 uF
AMIN (39)
AM\n Input Amplitude Viy (AM) 20.5 Vp-p
®
As
both
FMjn
and
AMjy
have
a
built-in
input
amplifier,
a
signal
shall
be
applied with
a
capaciter
connected.
®
Under
the
inhibit
state
and
at
AM
(MW/LW),
PSC
output
is
fixed
at
‘’L”’
level.
©
{F
offset
has
been
provided
in
advance
for
frequency
division
by
the
programmable
counter.
3. Phase Comparator
The phase comparator is a unit that compares phases of reference frequency and programmable counter output and controls
Veo through the low pass filter so that thus two signal frequencies and phases agree each other.
@ Two tri-state buffers DO-1 and DO-2 are transmitted parallely from one phase comparator. Because of this, two sets of
low-pass filter can be used without necessity for switching them.
@ Under the inhibit state, both DO-1 and DO-2 outputs are kept at ‘’L”’ level.
Reference R
Frequency
Phase (35) Do-1
Programmable _S Comparator
Count Output
(34) DO-2 High Impedance State
DO Output Timing Chart
@ Control Unit
1. Determination of OSC1 and OSC2 Oscillation Frequency
OSC1 and OSC2 are C and R connecting terminals of a single terminal type oscillator. Scan speed at time of manual fast
forward and auto search is decided by this frequency.
OSC1 is for FM and OSC2 is for AM and oscillation frequency can be set independently. Further, OSC1 oscillation frequen-
cy also seves for deciding manual fast forward pushing time, muting signal transmission time and store state automatic re-
leasing time.
Both OSC1 and OSC2 stop oscillation unless it is required.
Oscillation Frequency Fosc = (Hz) (Note 2)
1
0.7 CxRx
(Note 1} Rx = 10k ~ 100kQ
12