Kenwood TS-440S Service Manual page 6

TS-440S
I = 1 800, J = 7 2 44, K = 1 9 800, L = 3 2 39, M = 4 1
:. f1N = 0 . 3 8 8 fsrn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When f 1N = 30 MHz (US B mode) in formula
fsrn h a v e the following relation ship:
I = 1 8 00, J = 7 2 44, K = 1 9 800, L = 3 2 39, M = 73
:. f1N = 0 . 8 3 3 fsrn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Since the precision of the reference c rystal oscillator used
in the TS-440 is 1 0 ppm ( - 1 0 to 50°C) a n d the receiver
system has the characteristics sho w n in items i) and ii), the
total accu racy is sta ble at any point from 30 kHz to 30 MHz .
The maximum amo u nt of freq u e n cy shift is o n ly
Hz (see formula 1 2
iii) e n a b l e s varia ble b a n d f u n ctio n s s u ch as IF shift to be im­
pleme nted, using the mic roproce s s o r . The microprocessor
also is used to set carrier points by adju sting
a n d adj ust the amo u nt of IF shift .
So far received freq u e n cies in the S S B mode have been dis-
3 . Receiver Circuit Description
6
CIRCU IT D ESCR I PTION
1 0
+I
). The cha racteristic sho w n in item
f c AR,
a n d to set
F2
030-33
07,8
CFI
3 S K 7 3G R x 2
F M
CF 3
C F W 455
Fig . 3 Receiver circuit configu ration
cussed . For re ceive mod e s other tha n S S B, and in tran smit
1 1 mode, ope rating freq u e n cy is determined by the refe rence
freq u e n cy and freq u e n cy division d at a .
, f1N a n d
In CW receive mode,
f vc o 3 .
as In A M o r F M receive mode,
stopped . In F M receive mode, fHET is mod u l ated by adding
a u dio sig n als to VC 0 5 from the micropho n e . FSK (RTTY) is
1 2
transmitted in LS B mode and uses AFS K by adding audio sig­
n als extern ally .
The type of freq u e n cy dis p l ayed diffe rs, d e pe n ding on the
mode, as shown in Ta ble 1 .
- 300
M o d e
U S B , L S B , F S K
c w
A M , F M
012
2 S C 2459BL
f vc o
i s shifted d o w n 8 0 0 H z a n d used
f c AR
D i s p l a y e d freq u e n c y
C a rr i e r p o i n t f r e q u e n c y
Tra n s m i s s i o n c a rr i e r freq u e n c y
IF f i l t e r c e n t e r freq u e n c y
Ta ble 1 Dis played frequencies
IC 7
g e n e ration is