Figure 3-5. Connection for loop mode

TM 11-6625-922-15

(3) Operate SWEEP CALIBRATE switch to

dbm/1% MODULATION meter, for example:

LOW CAL.

(4) Operate the CARRIER FREQUENCY control

TRANSMIT

dbm/%

Output

to the desired low end frequency, monitored on the

LEVEL DBM

MODULATION

level

FREQUENCY display, of the frequency band to be

switch

meter

swept.

(5) Operate the SWEEP CALIBRATE switch to

-10

-3 DB

-13 DBM

HIGH CAL.

0 DB

0 DBM

(6) Operate the SWEEP WIDTH control to the

+10

-5 DB

+ 5 DBM

desired high end frequency, monitored on the

FREQUENCY display, of the frequency band to be

m. Operate the RANGE (KHZ) switch to the desired

swept.

frequency range. To operate between 100 Hz and 50

(7) Operate the SWEEP CALIBRATE switch to

kHz, use the .1-50 position. If operating in the 50- to

SWEEP. The output signal will automatically sweep

552-kHz range, use the 50-600 position.

between the frequency limits set up at LOW CAL and

HIGH CAL positions. The rate of the frequency sweep

n. The CARRIER FREQUENCY control is used to

is adjustable by the SWEEP TIME control.

vary the transmit signal within the desired range. This

control can vary the signal out of the ranges, but

p. Connect the input signal to either RECEIVE jack

operation should be maintained within the designated

of the TS-2669/GCM. This is the signal which is

ranges. The reference frequency can also be used by

obtained from the opposite end of the transmission path

operating the SWEEP - CARRIER - REFERENCE

to which the transmit signal is connected. The 75 Ω

switch to REFERENCE and using the REFERENCE

FREQUENCY control as described for the CARRIER

UNBAL RECEIVE jack is used only for 75-ohm

FREQUENCY control. The reference frequency will

impedances in the frequency range from 50 kHz to 552

also be transmitted at the TRANSMIT jacks. It is used

kHz. The BAL RECEIVE jack is used for 130/135-, 150-

as a fixed reference frequency in the band of operation

, 600-, and 900-ohm impedances in the frequency range

which can always be returned to in order to check for

from 0.1 kHz to 110 kHz.

drift in measurements without having to crank the

CARRIER FREQUENCY control all the way back. The

Caution: Do not connect the BAL

CARRIER FREQUENCY control is normally used to

RECEIVE jack directly to a line

make all measurements and the REFERENCE

having a dc potential. Use external

FREQUENCY control is left at a fixed frequency.

coupling

capacitors

for

these

connections.

o. Operate the TS-2669/GCM in the sweep mode

for the signal frequency as follows:

q. Operate the RECEIVE IMPEDANCE Ω switch to

the proper position to match the transmission line being

(1) Operate SWEEP-CARRIER-REFERENCE

used.

switch to SWEEP.

Operate the % MOD-RECEIVE LEVEL-

(2) Operate RANGE (KHZ) switch to desired

TRANSMIT LEVEL switch to RECEIVE LEVEL. Monitor

frequency range of operation.

the level at the RECEIVE jacks on the dbm/%

MODULATION meter.

Figure 3-5. Connection for loop mode.

3-7