MATCHING UNIT TF1790 (Figures 7-5 and 7-6)

T.O. 31W2-4-206-2

TM 11-5805-622-14/1

4-37. At terminal B, one amplifier TF3333-5 is

Channel Modem bandpass filter at terminals 4 and 5.

used in the transmit path to supply the 556.6 to 559.7

The 15 kHz carrier signal divided by transformer T3

kHz transmit signal to the directional coupler. The

is applied to the bridge circuit consisting of diodes

received 16.3 to 19.4 kHz signal IS passed in a

CR7 through CR10. The 16.3 to 19.4 kHz is demodu-

through connection TF1700 to the matching circuit

lated at L21 of the bandpass filter with the resultant

and channel modulator.

0.3 to 3.4 kHz VF band fed to an input filter circuit

consisting of L4, C10, C11 and C9 to reject all but

the VF frequencies. The receive level is adjusted by

4-38. DIRECTIONAL COUPLER TF1788 (Figure 7-2).

R15 before the signal is coupled to the receive ampli-

4-39. The directional coupler TF1788 serves to direct

fier circuit by transformer T4. Following amplifi-

incoming and outgoing signals through the orderwire

cation through transistors Q2, Q3 and Q4 the VF sig-

circuit. At terminal A, the 16.3 to 19.4 kHz trans-

nal is applied to a filter circuit consisting of C18,

mit signal is fed to the sable out system while the

C19, C20, C21, L6, L7 and L8 which further re-

556.6 to 559.7 kHz receive signal is directed to the

stricts the bandwidth. Transformer T6 couples the

receive circuit.

signal to the output terminals 1 and 2 for transmittal

to the VF Interface Matching Unit.

4-40. The frequency discrimination is accomplished

through the use of bandpass filter circuits. At ter-

4-31. MATCHING UNIT TF1790 (Figures 7-5 and

minal A, a transmit signal of 16.3 to 19.4 kHz applied

7-6).

to terminals 1 and 2 from the amplifier, passes

through the filter consisting of L1, L2, Cl, C2 and

4-32. The Matching Unit TF1790 although comprised

C3. The output to the cable appears at terminals 5

of the same components is wired differently for use in

and 6. At the same time the 556.6 to 559.7 kHz re-

terminal A orderwire equipment than it is for termi-

ceive signal at terminals 5 and 6 is coupled through

nal B. In the terminal A transmit path, the modulated

transformer T1 and appears at terminals 20 and 21

VF Signal of 16.3 to 19.4 kHz is applied to terminals

for transmittal to the receive amplifier.

1 and 2 of the matching unit card. Impedance match-

ing to the amplifier stage is accomplished through

transformer T1. In the terminal B receive path this

4-41. At terminal B, a transmit signal of 556.6 to

dance matching device between

unit serves as as

559.7 kHz is directed through the coupler and appears

the through connection and the Channel Modem.

as an output at terminals 5 and 6 while the 16.3 to

19.4 kHz receive signal at terminals 5 and 6 is

4-33. DIRECTIONAL MODULATOR TF1789

coupled through transformer T1 and appears at ter-

(Figure FO-10).

minals 20 and 21 for transmittal to the through con-

&or.

4-34.

4-42. 16 AND 576kHz CARRIER SUPPLY TF1792

(Figure FO-11),

4-43.

4-44

4-45

4-35

4-36.

4-46.

4-6