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500mw
LEVEL DIAGRAM
CIRCUIT DESCRIPTION
The model TK-230 consists of a TX-RX unit, a con-
The transmit signal is generated by the PLL VCO and
200mvrmS
20mVrmsS
{2Omvrms
IF
|
: IN AFO
2
+13.0dBy
{(-82.0dBm)
(-940dBm)
+25.0dBy
—-14.0dBu
(-—l21.0dBm)
-I40dBu
(IZ1.0dBm)
-13.0dBp
(-120.0aBm
ANT
1
RX SECTION
SSG
OUTPUT:
162.1MHz/21.4MHz,
MOD:
1kHz,
DEV:
3.0kHz
1.
3. SSG
output
was
measured
using
a 1000pF
capacitor.
TX SECTION
AF (IKHz)
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be is)
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wus
ANT
is terminated
with
509.
3. Level
was
measured
using
high
impedance
type
voltmeter
2. DC power
supply:
7.5V
1.
type, and it consists of a 12.5MHz temperature com-
pensated crystal oscillator (TCXO), a PLL sub-unit and
a voltage-controlled oscillator (VCO) sub-unit.
The frequency synthesizer phase locked loop is com-
mon for both the transmitter and the receiver sections
except for the VCO, which contains dedicated oscillator
sections for the transmitter and the receiver.
* Receiver PLL (RX PLL)
In the receive mode, the RX PLL is formed by the PLL
sub-unit and Q1 in the VCO sub-unit with a reference
signal supplied from the TCXO.
Q1
(25K508),
RF oscillator,
in the VCO
sub-unit
generates a signal for the first local oscillator injection.
24
signal according to the mode of operation and when the
transceiver is in the receive mode, the RF signal is fed
through a 3dB attenuator before being applied to the RX
first mixer (Q14),
A portion of the above VCO output signal is sampled
and buffer amplified by Q12. The output signal of Q12
is applied to IC1 in the PLL sub-unit, where the signal
is divided by a dual modulus type programmable coun-
ter to become a 5.0kHz signal. The 5.0kHz reference sig-
nai is obtained by dividing the 12.5MHz TCXO output
signal, which has a frequency stability of + 2ppm from
— 30 degrees C to + 60 degrees C, at the fixed counter
section of IC1. Those two 5.0kHz signals are compared
at the phase detector section of IC1 and any error in
FS kK
trol unit and a microphone unit. The TX-RX unit has four
is routed to the antenna after being amplified by the pow-
Se
J
sub-units and six module units. In addition, the optional
er amplifier section. (Figure 1)
KDM-4 signaling unit may be added to TK-230.
fr=ft—21.4MHz
©
1.FREQUENCY
ORGANIZATION
Range
fr (L.O.)
fr
Ke
TK-230 incorporates a phase locked loop (PLL) digi-
-
3
tal frequency synthesizer, operating
with a 5kHz chan-
Fl: 150~174MHz | 128.6 ~152.6MHz
150
~ 174MHz
5
7
g
<x"
nel spacing.
F2: 134~150MHz | 112.6~128.6MHz
134 ~ 150MHz
To
The receiver is a double conversion superheterodyne
i
io
with the first and second IF frequencies set at 21.4MHz
=
and 455kHz. An incoming signal from the antenna is
=
zd 4
mixed with the first local oscillator
(L.O.) signal to
&
z a
produce the 21.4MHz first IF signal. This is mixed again
a $
»
with the 20.945MHz second L.O. signal to produce the
=
tT.
=
455kHz second IF signal.
§
"To
©
CF 455KHz2
iS
i
uJ
2°
150~ 174MHz
x2
134~ 150MH
-AMHz
° z
;
1st MIX
MCF
SP
€
_
a
A
y
'
ANT SW
>
RF AMP)
—-——>}|
i
2nd MIX
IF DET
|
= AF AMP
———
s
—
a
&
5)
A
h
r
a
us
3
&S5 20.945MHz
<3
Y
ao
_Y
3
A
n
E
Pl
§ ————-+] 0
q
©
=
°
:
:
=
S
_V
K,M
128.6
~ 152.6MHz
§
>o
A
M2
112,.6~128.6MHz
MIC
s
°
3
=
<
<_
PLL vco
[ee
MiC AMP
£
>
Ao
:
TX RF AMP
TXDRIVE
|
KM
150.0~ 174.0MHz
o
2
-
M2
134.0~ 150.0MHz
g
°
Fig. 1 Frequency Organization
c
3——_—-
>
's)
=
;
.
,
oe:
5
S
2.TX-RX UNIT
This RF signal is amplified by buffer amplifiers Q3 and
=
3
w
1. PLL Frequency Synthesizer
04 before it is routed to the TX-RX unit where the signal
oy
2
4
The frequency synthesizer is a dual modulus prescaled
is switched by a switching diode (D4). D4 steers the RF
=
oO
i
&
7
jeg
a
.
ao
3
6
>
3S
8
3
c
2
2)
oO
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nw
3
=
=
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