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TS-440
S
CIRCUIT DESCRIPTIO
N
ANT
Fig
. 2 PLL frequency configuratio
n
30
K
30MHz
1st MIX
MIX
3rd MI
X
2nd
D
AF OU
T
DE
T
/
\
I
5 KHZ
I
6
.22MHZ
P
D
120KHZI
1= 1800 1=450
1
J=72441=1811
1
FM
MOD
I
/
1
I
HI
IPLL 5
1
I I F
M
MIX 5
4
.55MH
AMR,FM
R
AMT, FMT
: 455 KH
z
USB, CW
: 456
.
5
LSB,
FSK
: 453
.
5
CA
R
1/1
0
IX 4
9
.9—10 4MH
1/2
0
1/
5
IPLL
31
I/1
0
MKR —
(=13720_
.20719)
1 1
RIT, XI
T
Y
I/L
11/180
0
L=19800
`_
MN614
7
20799
4
P
.D
99=104MH
z
(98_6 =103
.6MHZ
)
—
5KHZ
—
I
M=323
9
299 4
STEP 5
)Cw
R
1
/P
o
r
I
/P-
I
F
P
I/1
---
-
7006 J
58
.25-
u
53
.25MHz
BP
F
r
1
I
p,D
I/
M
}
20KH
Z
1/450
AM,FM
: 91 MH
z
USB,CW
: 91
.3 MH
z
LSB,FSK
: 90
.7MH
z
IPLL4I
I
AM,FM
: K=1820
0
USB,
CW
K=1826
0
LSB,FSK
K=1814
0
IPLL
11
D
I/N,I/A--L
1
8
SOOKHZ
INT=13-
.73
T _ MN614
7
NT=PN-A
L—
—
I
91 MH
z
/'
—
1
I
.98^-2
.08MH
z
64
.78
=
59
.88MHz
P
.D
5KH
z
I/K
1/180
0
—
As shown in figure 2, all received frequencies excluding th
e
local oscillator frequency fLo are generated in the PLL circuit
.
The frequencies generated in these loops are expressed a
s
follows
:
-
fsT
D
VC04
:
f
K04
4
800 •
. fvco4 = 7200 fSTD
. . .
3
.fsTD
L
VCO3
: fvLos =
4
800
fvcos = 7200 fSTD
. . . .
4
fvcoz + fvco3 + fvco4
1
'fsT
D
50
20
4
M
45 0
M
fsTD
fvco
_ s
fvco4
5
fvcoz = 1800
50
2
0
VC01
:
N
1
8
:
.
fvcos = 72 fSTD + fLo +
f
STD
f
1
002
. .
6
Based on these formulas, the frequencies fvcor fHET,
and
fCA
R
are expressed as follows
:
/
N
M
L
fvco
= fvcor =
(
72
1800 + 3600000
K
+ 1440000 + 1) fsTD + fLo
7
J
f
HET = fVCO5 = 41
fSTD
8
Formula 1 may now be rewritten as follows
:
N _
M
L
J
fIN 1
72
180000 + 3600000
41 +
1
)
.
fsT
D
1
0
Note that f
L
o
is
not included in formula 10
. That is,
a
received frequency is determined by the reference frequen-
cy fs
TD
and frequency division data
Ito
N
. Further analysi
s
of formula
10 shows the following
:
i)
Basically, frequency division data I to N contain no er-
ror because they are controlled by the microproces-
sor according to the operating frequency
.
ii)
The accuracy of the operating frequency is equal t
o
that of the reference frequency, because all frequen-
cies other than fs
TD
in formula 10 are determine
d
by the microprocessor
.
iii)
The operating frequency does not change even if k o
r
fLo changes
.
When f
IN
= 14 MHz (USB mode) in formula 10 , f
IN
an
d
f
STD have the following relationship
:
VCO5
:
fvcos
4 fsTD
fvcos =
J
I
4
1
fSTD
2
VCO2
:
fvcos — f
L
o — fSTD + fvcoz
1
f
10
4
sTD
fvco4
K
fcAR
200
1440000
fSTD
9
5