Kenwood TS-60S Service Manual page 5

CIRCUIT DESCRIPTION
Receiver Circuit Configuration
The second IF signal of 10.695MHz is split into two.
The configuration of the receiver circuit is double-
One signal goes to the NB amplifier, and the other
conversion with a first IF of 73.045MHz and a second
passes through the NB gate FET (3SK131). The signal
IF of 10.695 MHz. and tripleconversion in FM mode
then passes through the CF (XF2) and is detected by
IC2 (KCD04) in FM mode. In other modes, the signal
with a first IF
Of
73.045MHz' a second I F
Of
goes to the IF filter of the X48-3110-00 unit. There are
10.695MHz, and a third IF of 455kHz. (Fig. 5)
The incoming signal from the antenna passes
three types of IF filter: 6-kHz. 2.7-kHz, and 500-Hz (500-
through the antenna switch relay on the filter unit, then
Hz is optional). The signal passing through the IF filter
goes to IC3 (KCD08), and is productdetected in SSB
through the ~ O - M H z low-pass filter. and goes to the
and CW modes, and envelope-detected in AM mode,
TX-RX unit. The sianal oasses throuah a 20dB attenu-
- ,
-
ator and 54-MHz low-pass filter in the TX-RX unit, and
goes through the band-pass filters. If AIP is off, the
signal passing through band-pass filter is amplified by
the RF amplifier, Q9. Q10 and Q69 (2SK520x
3),
and is
input to the first mixer, Q5 to Q8 (2SK520 x 4). If AIP is
-
on, the signal bypasses Q9.010 and Q69 and goes di-
rectly to the first mixer. It is mixed with the LO1 signal
by the first mixer t o produce a first IF signal of
73.045MHz.
The first IF signal of 73.045MHz passes through the
MCF (XFl), is amplified by Q17 (3SK131), and mixed
with the 62.35-MHz LO2 signal by the second mixer.
Q18 and Q19 (2SK520 x 2). to oroduce a second IF
1. Receiver front-end
The signal input to the TX-RX unit passes through
the switching circuit of the attenuator and the 60-MHz
low-pass filter, and goes to band-pass filters. If AIP is
off, D49 and D l 1 turn on and D8 and D9 turn off, and
the signal passing through filter is amplified by about
10 dB by Q9, Q10 and Q69 (2SK520 x 3) and output to
the first mixer. If AIP is on, D49 and D l 1 turn off and
D8 and D9 turn on, and the signal is output directly to
the first mixer without passing through 09, Q10 and
Q69. The first mixer, is a quad balanced mixer, Q5 to
0 8 (2SK520 x
4).
(Fig. 4)
signal of 10.695MHz.
TX-RX UNIT 1x57-4570-00)
Fig. 4 Receiver front-end