CIRCUIT DESCRIPTION
6-12
September 1994
Part No. 001-2008-300
8. Transmit Audio Modulation
9. High Stability Exciter Lock Detector
10.Exciter Lock Detector
11. Receiver Detector Audio
12.Receive Signal Strength Indicator
13.Receiver Injection Level
14.High Stability Receive Lock Detector
15.Receiver Lock Detector
16.Fan Current 1
17.Fan Current 2
18.Fan 1 On Sense
19.Power Supply Temp
20.Battery Voltage
21.High-Low Power
Pin 28
RF DATA
A data pin with TTL levels from the Controller
which has the dual role of loading the synthesizer
chips and adjusting the power control D/A lines for
proper output power. Up to four synthesizer chips and
a shift-register could be connected to this pin.
Pin 29
SYN CS RX
This is the chip select pin for the main receiver
synthesizer chip. This chip is the same part as used in
the Exciter. A low loads the synthesizer.
Pin 30
RSSI
This pin is the Receive Signal Strength Indication
to the Controller. This RSSI is used for tune-up of the
Receiver front-end during factory test mode. The
dynamic range is 40-60 dB. It will have an output
from an op-amp with the voltage going from 0.5V to
4.5V. The level will have an adjustment in the
Receiver.
Pin 31
GROUND
Carries ground current between the RFIB and
Chassis Backplane.
Pin 32
-
36
UNUSED
6.4.3 FAN CONNECTORS (J104/J105)
The outputs to the fan connectors are 4-pin plug-
in terminals that supply DC voltage. The plug on the
fan is a 2-pin connector. The plug-in terminals are
located on the back of the RFIB.
Pin 1
FAN 1 LOW
The ground return for the motor in Fan 1.
Pin 2
FAN HI
Connected to Pin 4. Carries the voltage to Fan 1
and/or Fan 2. The current is 1/4A nominal at 20V to
30V. This pin goes high when the PA heat sensor rises
above 50
°
C and goes low below 42
°
C.
Pin 3
FAN2 LO
Ground return for the motor of Fan 2.
Pin 4
FAN HI
Connected to Pin 2. Carries the voltage to Fan 1
or Fan 2. The Voltage is 20V-30V at 1/4A nominal.
This pin goes high when the PA heat sensor rises
above 50
°
C and goes low below 42
°
C.
6.4.4 POWER AMPLIFIER CONNECTIONS
WO 116
+26V DC
This capacitive feedthrough pin is at +26.5V DC
and carries the PA current, 12A nominal at 75W from
the RFIB to the Power Amplifier board.
WO 117
+26V DC GROUND
This capacitive feedthrough pin carries ground
current from the RFIB to the Power Amplifier board.
It must be capable of carrying up to 20A.
WO 118
+15V DC
This capacitive feedthrough pin co15V
DC from the RFIB to the PA, Exciter, and Forward/
Reverse Power Detect boards. Maximum current han-
dling is 6A (1.5A nominal at 75W).
WO 119
UNUSED
