Kenwood TS-2000, Service Manual

Page: 6 / 171

6
TS-2000/X
Display frequency LO1 OUT IC412ÅF DDS output (MHz)
f
RX
(MHz) (MHz) LMX2306TMX IC407 : AD9835BRU
Start Stop R N
420.000000 (K) 425.999999 (K) LO1 16 726 f
DDS
425.000000 (K) 431.499999 (K) = f
RX
– IF 736
=
f
RX
– IF
*R
430.000000 (E) N
431.500000 (K,E) 435.499999 (K,E) 747
435.500000 (K,E) 439.499999 (K,E) 754
439.500000 (K,E) 443.499999 (K) 762
440.000000 (E)
443.500000 (K) 447.999999 (K) 770
448.000000 (K) 449.999999 (K) 778
IF = RX : 41.895
TX : 41.795
Table 3 Main UHF band frequency configuration
SUB LO1
When the sub band receiver is operating, the sub VCO
(Q406, Q407) generates 322.95 to 465.040MHz. (See Table
4, frequency configuration.)
The 15.6MHz reference signal fstd is input to pin 8 of the
PLL IC (IC402) for the sub VCO, divided into 1/R in IC402 to
produce comparison frequency fø of 5 and 6.25kHz. The
division ratio data comes from the control unit.
The output signal from the VCO (Q406, Q407) goes to pin
6 of IC402, its frequency is divided into 1/N in IC402, com-
pared with comparison frequency fø by a phase comparator,
and locked.
Display frequency SLO1 OUT IC404 : IC402 : LMX2316TMX
f
RX
(MHz) (MHz) BU4094BCFV Step : 5,10,15,20,30 (kHz) Step : 6.25,12.5,25,50,100 (kHz)
13pin : Q6 12pin : Q7 11pin : Q8 R N R N
Start Stop (BSW2) (BSW1) (B LU SW) Formula Formula
118.00000 (K) 118.94500 (K) SLO1 L H L 3120
N =
2 x (f
RX
+ 58.525) 2496
N =
2 x (f
RX
+ 58.525)
118.95000 (K) 134.99500 (K) = (f
RX
+ 58.525) *2 H L 0.005 0.00625
135.00000 (K) 154.49500 (K) L H H
144.00000 (E) 146.00000 (E)
154.50000 (K) 173.99500 (K) H L
220.00000 (K) 235.99500 (K) SLO1 L H L
N =
2 x (f
RX
– 58.525)
N =
2 x (f
RX
– 58.525)
236.00000 (K) 252.49500 (K) = (f
RX
– 58.525) *2 H L 0.005 0.00625
252.50000 (K) 271.54500 (K) L H H
271.55000 (K) 289.99375 (K) H L
290.00000 (K) 296.42000 (K) SLO1 L H L
N =
f
RX
+ 58.525
N =
f
RX
+ 58.525
296.42500 (K) 328.99500 (K) = f
RX
+ 58.525 H L 0.005 0.00625
329.00000 (K) 367.52000 (K) L H H
367.52500 (K) 399.99500 (K) H L
400.00000 (K) 413.47000 (K) SLO1 L H L
N =
f
RX
– 58.525
N =
f
RX
– 58.525
413.47500 (K) 445.99500 (K) = f
RX
– 58.525 H L 0.005 0.00625
430.00000 (E) 440.00000 (E)
446.00000 (K) 484.57000 (K) L H H
484.57500 (K) 511.99500 (K) H L
The output signal from the VCO (Q406, Q407) passes
through a buffer amplifier (Q413, Q414), is amplified by the
broad-band amplifier (IC405), and passes through a low-pass
filter. The impedance is converted by an attenuator and the
signal is output as SLO1.
When the sub band receiver is not operating, Q411 and
Q411 are turned OFF with the BSW1 and BSW2 signals and
sub VCO (Q406, Q407) stops operation.
Table 4 Sub band frequency configuration
CIRCUIT DESCRIPTION