Kenwood TS-2000, Service Manual

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4
TS-2000/X
HF LO2
When the HF and or 50MHz band is operating, the
HF LO2 VCO (Q409) generates 65.230 to 58.390MHz. (See
Table 1, frequency configuration.)
The 15.6MHz reference signal fstd is input to pin 8 of the
PLL IC (IC401) for HF LO2, divided into 1/226 and 1/319 in
IC401 to produce comparison frequency fø of 69.027 to
48.903kHz.
The output signal from the VCO (Q409) goes to pin 6 of
IC401, its frequency is divided into 1/945 and 1/1194 in
IC401, compared with comparison frequency fø by a phase
Display frequency LO1 OUT IC414 : HF REF IC409 : DDS output (MHz)
f
RX
(MHz) (MHz) LMX2306TMX (MHz) LMX2306TMX IC408 : AD9835BRU
Start Stop R1 N1 N2 R2
0.030000 1.999999 LO1 32 76 HF REF 64 16 f
DDS
2.000000 5.999999 = f
RX
+ IF 30 75
=
(f
RX
+ IF)
*R1 =
HF REF
*R2
6.000000 8.999999 32 84 N1 N2
9.000000 12.999999 30 75
13.000000 16.999999 32 84
17.000000 17.999999 32 92
18.000000 21.999999 30 90
22.000000 23.999999 32 100
24.000000 24.999999 32 92
25.000000 25.999999 30 90
26.000000 29.999999 24 78
30.000000 32.999999 32 100
33.000000 36.999999 30 97
37.000000 40.999999 32 115
41.000000 44.999999 32 119
45.000000 48.999999 30 115
49.000000 51.999999 30 113
52.000000 55.999999 30 115
56.000000 60.000000 32 127
LO2 OUT IC401 : IF
(MHz) LMX2306TMX
N3 R3 RX TX
65.230088 945 226 75.925088 75.825088
58.389969 1194 319 69.084968 68.984968
65.230088 945 226 75.925088 75.825088
58.389969 1194 319 69.084968 68.984968
65.230088 945 226 75.925088 75.825088
58.389969 1194 319 69.084968 68.984968
65.230088 945 226 75.925088 75.825088
58.389969 1194 319 69.084968 68.984968
comparator, and locked. The division ratio data comes from
the control unit.
The output signal from the VCO (Q409) passes through a
buffer amplifier (Q415), is amplified by Q421, and passes
through a low-pass filter. The impedance is converted by an
attenuator and the signal is output as HF LO2.
When the HF and or 50MHz band is not operating, Q403
is turned OFF with the LO2SEL signal and HF LO2 VCO
(Q409) stops operation.
Table 1 Main HF and 50MHz band frequency configuration
CIRCUIT DESCRIPTION