VXR-9000 UHF Service Manual
squelch threshold level to that which is memorized in EE-
PROM
Q3006
(
BR24L32F
) or set by the front panel
SQL
control.
RX PLL
AND
VCO C
IRCUITS
The receiver’s PLL circuitry consists of PLL subsystem IC
Q1052
(
MB15A02PFV1
) on the MAIN Unit, which con-
tains a reference oscillator/divider, serial-to-parallel data
latch, programmable divider, phase comparator and a
swallow counter. Stability is obtained by a regulated 5
VDC supply via
Q1062
(
L78M05T
) and temperature com-
pensated 14.4 MHz crystal oscillator
X1003
.
The RX VCO made up two VCO circuit, one is Low-Band
RX VCO, consisting of FET
Q1048
(
2SK508
) and varactor
diodes
D1018
and
D1019
(both
1SV282
), and another one
is High-Band RX VCO, consisting of FET
Q1049
(
2SK508
)
and varactor diodes
D1020
and
D1021
(both
1SV282
), os-
cillates between 376.65 MHz and 416.65 MHz according to
the programmed receiving frequency. The RX VCO out-
put passes through buffer amplifier
Q1059
(
2SC5226
) and
first local amplifier
Q1019
(
2SC3357
) to the first mixer
Q1018
(
SPM5001
), as described previously. A portion of
the RX VCO output is applied to the prescaler/swallow
counter section in the PLL IC
Q1052
(
MB15A02PFV1
).
There the RX VCO signal is divided by 64 or 65, according
to a control signal from the Main CPU
Q3014
(
HD64F2238
)
on the CNTL Unit, before being applied to the program-
m a b l e d i v i d e r s e c t i o n o f t h e P L L I C
Q 1 0 5 2
(
MB15A02PFV1
).
T h e d a t a l a t c h s e c t i o n o f t h e P L L I C
Q 1 0 5 2
(
MB15A02PFV1
) also receives serial dividing data from
the Main CPU
Q3014
(
HD64F2238
), which causes the pre-
divided RX VCO signal to be further divided by 75,330 ~
81,330 (or 60,264 ~ 65,064) in the programmable divider
section in the PLL IC
Q1052
(
MB15A02PFV1
), depend-
ing upon the desired receive frequency, so as to produce
a 5 kHz (or 6.25 kHz) derivative of the current RX VCO
frequency. Meanwhile, the reference divider section of the
PLL IC
Q1052
(
MB15A02PFV1
) divides the 14.4 MHz
crystal reference from the reference oscillator
X1003
and
Q1045
(
2SC4116GR
) by 2880 (or 2304) to produce the 5
kHz (or 6.25 kHz) loop reference.
The 5 kHz or 6.25 kHz signal from the programmable di-
vider (derived from the RX VCO) and that derived from
the crystal are applied to the phase detector section of the
PLL IC
Q1052
(
MB15A02PFV1
), which produces a pulsed
output with pulse duration depending on the phase dif-
ference between the input signals. This pulse train is then
converted to DC, low pass filtered, then fed back to the
RX VCO varactor diodes
D1018/D1019
and
D1020/D1021
(all
1SV282
).
Changes in the DC voltage applied to the varactor diodes
D1018/D1019
and
D1020/D1021
(all
1SV282
) affect the
reactance in the tank circuit RX VCO
Q1048/1049
(both
2SK508
), changing the oscillating frequency according to
the phase difference between the signals derived from the
RX VCO and the crystal reference oscillator. The RX VCO
is thus phase-locked to the reference frequency standard.
T
RANSMIT
S
IGNAL
P
ATH
The speech audio from the CNTL Unit is applied to the
varactor diode
D1010
(
HVU350
), which frequency mod-
ulates the TX VCO from the unmodulated carrier at the
transmit frequency. The modulated transmit signal is buff-
ered by
Q1026
(
2SC5226
), then passes through the RF
amplifier
Q1030
(
2SC3357
) and RF diode switch
D1016
(
RN739F
) to the PA Unit.
The transmit signal is applied to the RF amplifier
Q5001
(
2SC3357
) and
Q5008
(
PD55008
), then finally amplified
by power amplifier
Q5015
and
Q5016
(both
PD55025S
)
up to 50 Watts. Harmonic and spurious radiation in the
final output is suppressed by a low pass filter consisting
of coils L5007 ~ L5010, plus capacitors C5071, C5078,
C5082, C5085, and C5088 on the PA Unit, before delivery
to the TX antenna jack.
TX PLL
AND
VCO C
IRCUITS
The Transmitter’s PLL circuitry consists of PLL subsystem
IC
Q1008
(
MB15A02PFV1
) on the MAIN Unit, which con-
tains a reference oscillator/divider, serial-to-parallel data
latch, programmable divider, phase comparator and a
swallow counter. Stability is obtained by a regulated 5
VDC supply via
Q1062
(
L78M05T
) and temperature com-
pensated 14.4 MHz crystal oscillator
X1001
.
The TX VCO, consisting of FET
Q1021
(
2SK508
) and var-
actor diodes
D1008
and
D1009
(both
1SV282
), oscillates
between 450 MHz and 490 MHz according to the pro-
grammed transmit frequency. The theory of operation of
the remainder of the PLL circuitry is similar to that of the
RX PLL circuit; however, dividing data from the Main
CPU
Q3014
(
HD64F2238
) on the CNTL Unit is such that
the VCO frequency is the actual transmit frequency.
APC
(
A
UTOMATIC
P
OWER
C
ONTROL
)
RF power output from the final amplifier
Q5015
/
Q5016
(both
PD55025S
) is sampled by C5061/C5056 and is then
rectified by
D5007
and
D5008
(both
HSM88AS
). The re-
sulting DC voltage is applied to the comparator
Q5005
(
TA75S01F
), where the voltage is compared with a refer-
ence voltage from the Main CPU
Q3014
(
HD64F2238
) on
the CNTL Unit, to produce a control voltage for the Auto-
matic Power Controller
Q5004
(
2SC4116GR
) and
Q5002
(
2SB1122S
), which regulates supply voltage to
Q5001
(
2SC3357
).
Circuit Description
F-2
Содержание VXR-9000 Series
Страница 6: ...VXR 9000 UHF Service Manual B 4 DSUB 25 pin Accessory Connector Note ...
Страница 9: ...D 1 Block Diagam VXR 9000 UHF Service Manual MAIN Unit ...
Страница 10: ...D 2 Block Diagam VXR 9000 UHF Service Manual CNTL Unit PANEL Unit PA Unit ...
Страница 11: ...E 1 Connection Diagam VXR 9000 UHF Service Manual ...
Страница 12: ...E 2 Connection Diagam with Optional 100 W PA Unit VXR 9000 UHF Service Manual ...
Страница 16: ...VXR 9000 UHF Service Manual Circuit Description F 4 Note ...
Страница 24: ...VXR 9000 UHF Service Manual Alignment G 8 Note ...
Страница 26: ...MAIN Unit Lot 1 2 H 2 VXR 9000 UHF Service Manual Note ...
Страница 29: ...MAIN Unit Lot 3 24 H 5 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 30: ...MAIN Unit Lot 3 24 H 6 VXR 9000 UHF Service Manual Note ...
Страница 33: ...MAIN Unit Lot 25 H 9 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 34: ...MAIN Unit Lot 25 H 10 VXR 9000 UHF Service Manual Note ...
Страница 54: ...H 30 MAIN Unit Parts List VXR 9000 UHF Service Manual Note ...
Страница 55: ...CNTL Unit Lot 1 2 I 1 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 56: ...CNTL Unit Lot 1 2 I 2 VXR 9000 UHF Service Manual Note ...
Страница 59: ...CNTL Unit Lot 3 I 5 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 60: ...CNTL Unit Lot 3 I 6 VXR 9000 UHF Service Manual Note ...
Страница 72: ...I 18 CNTL Unit Parts List VXR 9000 UHF Service Manual Note ...
Страница 73: ...PANEL Unit J 1 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 74: ...PANEL Unit J 2 VXR 9000 UHF Service Manual Note ...
Страница 81: ...K 1 VXR 9000 UHF Service Manual Circuit Diagram PA Unit Lot 1 2 ...
Страница 82: ...K 2 VXR 9000 UHF Service Manual Note PA Unit Lot 1 2 ...
Страница 84: ...K 4 VXR 9000 UHF Service Manual Parts Layout Side B 1 3 5 2 4 b a d c f e g h PA Unit Lot 1 2 ...
Страница 85: ...K 5 VXR 9000 UHF Service Manual PA Unit Lot 3 20 Circuit Diagram ...
Страница 86: ...K 6 VXR 9000 UHF Service Manual PA Unit Lot 3 20 Note ...
Страница 88: ...K 8 VXR 9000 UHF Service Manual PA Unit Lot 3 20 Parts Layout Side B 1 3 5 2 4 b a d c f e g h ...
Страница 93: ...L 1 VXR 9000 UHF Service Manual Circuit Diagram PA 2 Unit Lot 21 ...
Страница 94: ...L 2 VXR 9000 UHF Service Manual Note PA 2 Unit Lot 21 ...
Страница 96: ...L 4 VXR 9000 UHF Service Manual Parts Layout Side B 1 3 5 2 4 b a d c f e g h PA 2 Unit Lot 21 ...
Страница 100: ...L 8 PA 2 Unit Lot 21 Parts List VXR 9000 UHF Service Manual Note ...
Страница 101: ...M 1 REG Unit VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 103: ...N 1 SUB Unit Lot 1 2 VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 105: ...O 1 100W PA Unit Option Version D VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 106: ...O 2 100W PA Unit Option Version D VXR 9000 UHF Service Manual Note ...
Страница 113: ...P 1 RELAY Unit Option VXR 9000 UHF Service Manual Circuit Diagram ...
Страница 117: ......