TK-8100H
17
■
Unlock Circuit
During reception, the 8RC signal goes high, the 8TC signal
goes low, and Q34 turns on. Q33 turns on and a voltage is
applied to the collector (8R). During transmission, the 8RC
signal goes low, the 8TC signal goes high and Q36 turns on.
Q35 turns on and a voltage is applied to 8T.
The CPU in the control unit monitors the PLL (IC401) LD
signal directly. When the PLL is unlocked during transmis-
sion, the PLL LD signal goes low. The CPU detects this sig-
nal and makes the 8TC signal low. When the 8TC signal goes
low, no voltage is applied to 8T, and no signal is transmitted.
IC101
CPU
Q34
SW
Q33
SW
IC401
PLL
Q36
SW
Q35
SW
LD
8RC
8C
8R
8T
8TC
PLL lock
: LD “H”
Fig. 7
Unlock circuit
Transmitter System
■
Outline
The transmitter circuit produces and amplifies the desired
frequency directly. It FM-modulates the carrier signal by
means of a varicap diode.
■
Power Amplifier Circuit
The transmit output signal from the VCO passes through
the transmission/reception selection diode (D409) and ampli-
fied by Q500, Q501, Q502 and Q503. The amplified signal
goes to the final amplifier (Q504) through a low-pass filter.
The low-pass filter removes unwanted high-frequency har-
monic components, and the resulting signal is goes the an-
tenna terminal.
■
APC Circuit
The automatic transmission power control (APC) circuit
detects part of a final amplifier (Q504) output with a diode
(D606, D607) and applies a voltage to IC501. IC501 com-
pares the APC control voltage (PC) generated by the D/A con-
verter (IC161) and DC amplifier (IC203) with the detection
output voltage. IC501 generates the voltage to control Q502,
Q503 and Q504 and stabilizes transmission output.
The APC circuit is configured to protect over current of
Q502, Q503 and Q504 due to fluctuations of the load at the
antenna end and to stabilize transmission output at voltage
and temperature variations.
RF
AMP
Q500
DRIVE
AMP2
Q503
DRIVE
AMP1
Q502
FINAL
AMP
Q504
PRE
DRIVE
AMP
Q501
DC
AMP
IC203
ANT
SW
D601~D604
LPF
ANT
POWER
DET
D606
D607
IC501
APC
CONTROL
D409
PC
IC161
3pin
VR1
Q411
RF AMP
2SC5108
(Y)
Q500
RF AMP
2SC5110
(O)
Q501
PRE
DRIVE AMP
2SC3356(R24)
Q503
ANT
DRIVE
AMP 2
PD55008TR
Q502
DRIVE
AMP 1
2SK2596
Q504
FINAL AMP
RD60HUF1
-01
IC161
Q406
D/A
CONVERTER
M62363FP
X401
TCXO
16.8MHz
VCO
2SK508NV
(K52)
IC401
PLL
MB15A02
Q410
BUFFER
2SC5108
(Y)
Q404
RF AMP
2SC4649
(N,P)
IC203
BUFFER
NJM2902V
IC101
IC161
MIC KEY
INPUT
CPU
30622MAA
-B76GP
D/A
CONVERTER
M62363FP
IC161
D/A
CONVERTER
M62363FP
IC203
SUM AMP
NJM2902V
IC202
IC201
MIC
MIC/IDC
NJM2100V
Splatter
FILTER
NJM2904V
Fig. 9
APC circuit
Fig. 8
Transmitter system
CIRCUIT DESCRIPTION
