Interface circuit card

TM 9-1240-369-34

range to the target exceeds the systems capacity, the

assemblies,

transmitter

logic,

transmitter

logic

9995 signal, developed when the counters are full and

components, boresight and field stop assembly

the min range signal, developed for a period immediately

photomultiplier, video amplifiers, A-trigger assemblies,

after laser pulse transmission in order to close the video

and a malfunction 3/buffer logic card.

(a) Transmitter logic and transmitter logic

gate to spurious nearby backscattered returns from

component cards. The transmitter logic circuit card

surface objects. The test range gate circuit applies a

test range signal to the video amplifier during the test

assembly performs these functions: switching for the Q-

mode. The reset and malfunction 8 logic circuitry

switch assembly senses the speed of the Q-switch motor

contains a flip-flop that is set to the malfunction state by

to provide triggering for the flashtube, and it generates

the reset signal, and reset to the nonmalfunction state by

the SCR-trigger signal for the reset flip-flop and the reset

inputs from 100-meter signals from each counter. Thus,

signal for the fire logic circuit in the PFN charge power

failure of any of the three counters to count results in

supply. The transmitter logic component assembly

generation of a malfunction 8 signal for application to the

contains the trigger transformer for firing the flashtube.

digital indicator.

When the fire signal is applied to the Q-switch power

(g) Interface circuit card. The interface circuit

switch circuit, a return path for the motor is closed and

card serves as an interface between the power supply

the motor starts. The motor coasts to a stop when the

control unit and the receiver-transmitter unit.

The

fire signal is removed. The Q-switch timing circuit acts in

interface circuit buffers and inverts the A-trigger, video

conjunction with the Q-switch speed sensing circuit to

min range inhibit and test range signals; generates the

determine when the motor has increased to the speed

malfunction 2 and 4 signals; and generates a +15 V

required before firing of the laser can occur. These

interlock to prevent the PEN from charging in the test

circuits compare the fixed-length pulse of a monostable

mode. The interface circuit receives the A-trigger and

multivibrator with the time interval of magnetic pickup

video signals from the malfunction 3/buffer logic card

pulses from the Q-switch. A linear ramp is generated in

and sends the A-trigger and video signals to the reply

the Q-switch timing circuit, and at the end of the timing

gating circuit. The interface card also receives the reset

cycle the SCR trigger timing logic circuit, if the Q-switch

signal from the R/T control unit and sends the reset (1)

speed is high enough, generates a signal that is inverted

signal to the counters and reply gating circuits. The reset

and applied to the flashtube trigger SCR. The SCR

(2) signal is sent from the interface card to the PEN

trigger timing logic simultaneously generates the SCR

charge power supply.

trigger signal.

(b) Transmitter component assembly. The

When the system is operating in the test mode the

test signal comes through transistor Q2 and inhibits the

transmitter

component

assembly

contains

the

generation of a +15 V interlock which in turn prevents the

recollimating transmitter telescope, the Q-switch

PEN from charging in the test mode.

assembly, the flashtube and ruby rod, and associated

Malfunction 2 is generated from malfunction 7 and

optics. The flashtube requires two voltages: a high

malfunction 8. Malfunction 7 and malfunction 8 are OR'd

voltage to fire it and a sustained voltage. Upon firing, the

together and when either is low, this causes the

flashtube trigger SCR dumps + 400 volts stored in a

commander's control unit MALF light to illuminate and a

capacitor through the primary of a transformer. A pulse

"2" readout to be seen on the RANGE (METERS)

of about + 10 kv developed in the secondary in series

indicator showing that a malfunction has occurred in

with the + 1200 V from the PFN ionizes the gas in the

either the reply gating or counters circuits. Malfunction 4

flashtube and the stored energy in the PFN dumps into

is generated as a result of fault in the PEN circuit. When

the flashtube sustaining its output until the laser pulse is

the RANGE switch is activated. the fire signal should

generated. An elliptical reflector directs the light from the

come through and clear the flip-flop circuit (Z, 5). If the

flashtube into the ruby rod. which forms an optical

fire signal is not generated, the flip-flop will go high and

resonant cavity with a reflective porro prism at one end.

cause the MALF light to illuminate, and a "4" readout to

two relay prisms with 4.5 degree hypotenuse angles to

be seen on the RANGE (METERS) indicator.

fold the beam 180 degrees, and a resonant reflector that

The test range signal comes in and is buffered and

is partially reflective and partially transmissive at the

sent to the malfunction 3 / buffer logic circuit.

output end. One of the relay prisms is mounted on the

(2) Receiver-transmitter unit.

The receiver-

Q-switch assembly. It is rotated at a specific speed to

transmitter unit consists of the following circuits or

govern the precise time of development of the laser

pulse; it serves as a "Q-spoiling" device except for a brief

instant when it is alined to form a resonant optical

1-7