Transmitter Frequency Multiplier Group 1A10 Circuit Functioning

TM 11-5820-695-35

are resont lines, with tuning provided by a plunger and

cuits is accomplished by a qurb-wave choke in the tuned

the input and output coupling is provided by adjustable

cavity. Two tuned stubs CA and CA suppress the

probe

fundamental LO. frequency The resulting sidebands are

reflected out of the diode cavity Z1 and enters coaxial

Coaxial circulator 1A10HY1 isolates the

circulator 1A9HY1 at port No. 2 (J2).

transmitter 2nd stage frequency multiplier from the

transmitter rd stage frequency multiplier. the input (J1

The coaxial circulator hs a bandpass from

INPUT) and output (J2 OUTPUT) impedance 6 are 0

4.4 to 5.0 GHz with a maximum insertion loss of 0.6 db

ohms resistive. The monitor output (J3 DC MONITOR)

(port 2 to port 3). This a four-port coaxial circulator with

provides a sample of the transmitter 2nd

stage

a resistive termination at

port 4.

The reflected

frequency multiplier output signal Level to the meter

sidebands enter the circulator at port No. 2 (J2) and

selector switch on meter panel assembly A15AS. The

leave at port No. 8 (J3). A tunable bandpass filter is

insertion Ioss for the circulator is 03 db maximum

connected at port No. 3 and is tuned to the desired

sideband which is passed by the filter. The unwanted

Transmitter 3rd stage frequency multiplier

sideband is reflected back to port No. 3 of the circulator

1A10A2 functions in a similar manner to the transmitter

which couples it to the dummy load at port 4.

2nd stage frequency multiplier. However since the

frequencies are higher, the input signal is coupled to the

diode type amplitude detector is

Varactor diode by a tuned cavity and the second

incorporated in the circulator for monitoring the local

harmonic output is selected by a single coaxial cavity.

oscillator chain pass band shape. The monitor dc

Tuning the coaxial cavity is provided by adjustable

output is taken from Connector J4.

probes

2-37.

Transmitter Frequency Multiplier Group

2-38.

Transmitter Amplifier-Frequency Multiplier

1A10 Circuit Functioning (fig. 2-17)

1A11 Circuit Functioning (fig. 5-27)

Transmitter frequency multiplier group

The transmitter amplifier-frequency multiplier amplifies

1A1010 multiplies the 113S75 to 121125 M local

and multiplies (times 4) the 2848-375 to 303.125 (20

oscillator frequency by four. The 4.55 to 4.85 GHz

millwatts, nominal ) input signal to a 1137.5 to 1212.5

output frequency is at a level of 1.7 watts (minimum)

MHz (8 watts, nominal) output signal. Transmitter

and is applied to transmitter frequency mixer stage 1A9.

amplifier-frequency multiplier 1A1-1 is encomprised of a

The transmitter frequency multiplier group consist of

300 to 600 MHz doubler, 600 MHz amplifier, isolator,

transmitter 2nd stage frequency multiplier 1A10A1

and a 600 to 1200 MHz frequency doubler.

(times 2), 22752425 KMHz e-vi-l circulator 1A10HY1,

and transmitter 3rd stage frequency multiplier 1A10A2

3 00 to 600 MHz Frequency Doubler. The

(times 2).

284.375 to 303.125 Hz signal from electrical frequency

synthesizer 1A.14 is applied to the primary of

The input signal to transmitter 2nd stage

transformer T1. The secondary of T1 is connected to

frequency multiplier 1A10A1 is applied to the low-pass

the anodes of diodes CR1 and CR2. This circuit is, in

filter consisting of C1, L1 and C2. Variable capacitor C1

effect, a full-wave rectifier, in which CR1 and CR2

provides impedance matching at the input. Series

alternately a half cycle of the input signal. Therefore,

variable capacitor C3 provides impedance matching to

the output frequency (568.760 to 606250 MHz) is twice

the varactor diode impedance (typically 1-10 ohms).

the input frequency. The 568.750 to 606.a60 MHz

The varactor diode is a step-recovery type. The step

signal is coupled to the base of Q1 in the G00 MHz

recovery diode stores a charge as it conducts in the

amplifier circuit through capacitors C1 and 051.

forward direction; when the applied voltage is reversed

Conductor 12 is used in conjunction with C1 and C51 to

the diode will conduct for a brief period in the reverse

filter out the 300 MHz component of the signal that

direction until the stored charge is removed, conduction

appears at the output of the full-wave rectifier. RI is a

then ceases abruptly. The abrupt step in current

dc load resistor and inductors L1 and IA are rf chokes.

through the diode produces a waveform that is rich in

harmonic power.

600 MHz Amplifier. The 600 MHz amplifier

The 2nd harmonic of the incoming frequency is selected

includes transistor stages Q1 to Q4

by tuned coaxial cavities Z11 and Z2A. These cavities

2-76

Change 5