Kenwood TS-5700 Service Manual page 11

TS-5700
• Signal-Strength Meter Circuit
In modes other than FM, the AGC voltage is inverted
and amplified by operational amplifier IC1: NJM2904M.
This output is used as the signal strength meter volt­
age. In FM mode, the level detection output from IC7:
KCD10 is used. The signal strength meter voltage in
each mode is switched by analog switch IC4:
BU4066BCFV and output to the control unit.
AGC
1
-----------------------------------
IF SC
E
Q
�
12
CIRCUIT DESCRIPTION
IC15: KCD11
....
a:
IC7: KCD10
a: N 0 U d
OO � U U'J U'J
C30
Fig. 8
Squelch Circuit
•
In FM mode, the noise detection voltage (FSQL) out­
put from IC7: KCD10 is sent to the control unit.
modes other than FM, the signal strength meter volt­
age is sent to the control unit. It is compared with the
voltage proportional to the angle of the SOL VR to con­
trol squelch opening and closing. The microcomputer
controls the delay time and hysterisis.
�
,
5
R2SS
FM
DET
FMS
AGC and S-meter circuits
AM SB
AMB DET SCB DET
SQ
]
CAR
E
(For control unit)
In
SF