Kenwood TS-2000 Service Manual page 7

1.2GHz Unit Local Oscillator
The 12LO31 signal (31.2MHz) is quadrupled to 124.8MHz
in Q14 and 15. This signal is sent to the mixers of the trans-
mitter section (Q1 and Q2) and the mixers of the receiver
section (Q7 and Q8)
In the DDS (C4) , 8.323~8.488MHz are output using
12LO31 as the reference signal. This signal passes through
a filter (CF1 and CF2) and is input to the mixers for reference
PLL signals (Q313 and 314).
In Q313 and Q314, the DDS output is mixed with
12LO31 (31.2MHz) and an approximately 39.6MHz signal is
obtained. This signal passes through a filter and an amplifier
(Q312) and becomes the reference signal of the PLL IC
(IC5).
The VCO (Q301) oscillates at 552.253~582.303MHz.
This signal is amplified in Q302 and goes to the PLL IC (IC5)
and Q19.
The PLL IC (IC5) divides the reference signal (approxi-
mately 39.6MHz) to 1/72. The signal from Q302 is divided to
1/N (N=1006~1058).
Start
1240.000000 (K)
1244.000000 (K)
1246.000000 (K)
1250.000000 (K)
1254.000000 (K)
1256.000000 (K)
1259.000000 (K)
1260.000000 (E)
1263.000000
1267.000000
1271.000000
1275.000000
1278.000000
1281.000000
1285.000000
1289.000000
1292.500000
1295.000000
1298.000000
CIRCUIT DESCRIPTION
Display frequency Q301 oscillation
f (MHz)
RF
Stop f
1243.999999 (K) f
VCO
1245.999999 (K) = (f
1249.999999 (K)
1253.999999 (K)
1255.999999 (K)
1258.999999 (K)
1262.999999
1266.999999
1270.999999
1274.999999
1277.999999
1280.999999
1284.999999
1288.999999
1292.499999
1294.999999
1297.999999
1299.999999
Table 5 1.2GHz band frequency configuration
The two signals are compared in the phase comparator
within the IC and the VCO (Q301) oscillation frequency is
locked.
The signal input into Q19 is doubled. This signal passes
through a filter and an amplifier (Q20) and goes to the send-
ing mixer (D1) and the receiving mixer (Q10).
TX-RX 3 (X57-607)
Q10 D8
RX
1104~
1165MHz
D11
D10
Q20
L52
Q19
IC5
TX
PLL
D1
Q302
Fig. 2 1.2GHz unit local oscillator
C5 : DDS output (MHz)
frequency LMX2316TMX IC4 : AD9851BRS
(MHz) R N
VCO
72 1006 f
DDS
– IF)/2 1008
RF
=
1011
1015
1017
1020
1023
1027
1030
1034
1037
1040
1043
1047
1050
1053
1056
1058
Local Signals
The RXLO3 (11.15MHz) and RCAR (467kHz) for reception
and TCAR (10.583MHz) for transmission are output from
DDSs (RXL03 : IC603, RCAR : IC601, TCAR : IC602).
The frequencies of local oscillator output signals (LO1,
LO2, RCAR, TCAR) for each band are shifted by offset (IF
filter setting), RIT, XIT, IF SHIFT as listed in Tables 5 to 11.
TS-2000/X
X57-606
Q65
Q7,8
LO31
RX
31.2MHz
Q15 L42,43 Q14
124.8MHz
Q310,311
Q1,2
TX
L340~
Q312 342 CF1,2 Q16
39.6 Q313,314 8.4 8.323~
MHz
39.523~ MHz 8.488MHz
Q301
39.688MHz
552.253~
582.303MHz
(f – IF)*R
RF
– 31.2
2*N
IF=RX : 135.495
TX : 135.395
12LO31
31.2MHz
31.2MHz
IC14 Q13
DDS
7