SECTION VI DESCRIPTION OF SYSTEM TIE-IN OF EQUIPMENT

T.O. 12P4-2APX-192

NAVAIR 16-35TS1843-1

TM 11-6625-1646-25

5-35. PRF GENERATOR (See figure FO-2) Part of Mode

approximately 6.5 volts are dropped. The remaining 5 volts is

Generator (A2). The PRF generator. A2Q1 Is activated

applied to the cathode of the 5.1 volts zener diode A3CR2.

whenever the power supply is energized. A2Q1 is a unijunction

A3CR2 maintains a constant 5.1 volts output with variations in

transistor which conducts when the voltage across A2C1

the 5.1 volt current demand.

reaches the triggering level of A2Q1. The charge rate of A2C1

5-34.

RF GENERATOR (A1A1) (See figure FO-5). RF

and the frequency of repetition is determined by A2R1. When

generation is accomplished by the use of a colpitts crystal

the charge across A2C1 is sufficient to fire A2Q1, a positive

controlled oscillator with in-phase capacitor feedback. The

pulse is developed across A2R2, and applied to the base of

oscillator is free running at 85.833 MHz whenever the power

A2Q2. A2Q2 amplifies and Inverts the pulse and routes the

supply is activated. The output of the oscillator is applied to a

pulse to the PRF enable NAND gate A2A3A, pin 9.

step recovery diode A1A1A4CR1. A1A1A4CR1 acts as a

5-36. CLOCK GENERATOR (See figure FO-2) Part of Mode

frequency multiplier providing a large number of harmonics.

Generator (A2). The one MHz clock source is provided by a

The one quarter wave guide selects the 12th harmonic, 1030

crystal controlled oscillator. The clock generator is energized

MHz, and applies the signal to A1A1A4CR2. A1A1A4CR2 is

whenever the power supply is activated.

Oscillation is

normally at a 0 volt potential until a pulse from the mode

maintained as a result of regenerative feedback through

generator applies voltage across A1A1A4CR2.

When

inverter A2A2E. A2Q3 provides isolation and some gain

A1A1A4CR2 conducts, RF transmission across the

between the oscillator and the clock NAND gate. The output

mechanical variable directional coupler (strip line type) is

of the clock generator is a string of positive-going square wave

achieved. In the Monitor mode of operation AlAlA5CR1 is

pulses spaced one-half usec apart going from approximately a

forward biased by a +5 volt output from A3Q8. When

+5 v as a high to approximately ground potential (0.5 to 0.7

AlAlA5CR1 is forward biased A1AlA4CR1 is reverse biased by

vdc) as a low.

+5 volts, thus preventing any RF generation.

SECTION VI

DESCRIPTION OF SYSTEM TIE-IN OF EQUIPMENT

INDEX OF DIAGRAMS

Figure

Title

Page

6-1

System Tie-in ...................................................................

6-2

6-1. GENERAL.

6-4. The TS-1843A/APX provides both In-Flight-testing and

monitoring of an IFF/SIF transponder system. The test set is

6-2. This section describes the integration of the Transponder

installed between the aircraft antenna system and transponder

Set, Test Set TS-1843A/APX into an operational IFF/SIF

set (figure 6-l)and controlled externally by a control unit. The

transponder system. The TS1843A/APX, at the present time,

control unit provides the means of selecting the desired mode

is intended for use with Transponder Sets AN/APX-64 and

of operation. The performance of the transponder system Is

AN/APX-72, but will perform satisfactorily with any equipment

evaluated on a go. no-go basis by sampling and analyzing the

compatible with the AIMS transponder characteristics.

transponder replies. The go or no-go indication is provided by

a TEST lamp also located on the control unit.

6-3. EQUIPMENT TIE-IN.

5-7/6-1