Figure 6-19. Station to station total peak and average bias telegraph teat.

TM 11-5895-1012-10

6-20. Total Peak and Average Bias Tele-

graph Distortion Test

(e) INPUT SELECT SWITCH to BRIDGING

H1Z.

(f) BAUD RATE SELECTOR to 75.

(g) DISTORTION SELECT to TOTAL PEAK.

(h) TRANSITION SELECT to ALL.

WARNING

(i) ALARM switch to RESET.

DANGEROUS VOLTAGES are present dur-

(3) Procedure.

ing the preparation of the test circuits speci-

(a) Turn on the power. If the distant station dis-

fied in figures 6-19 and 6-20. Turn all power

tortion analyzer signal lamp does not light, reverse the

switches off before constructing these test

polarity switch. At the transmitting station, transmit

circuits. Failure to observe safety precautions

the message "Quick Brown Fox".

could result in serious injury or death.

(b) At the receiving station, read the total peak

c. Station-to-Station Test. Contact distant station

distortion in percent and record it. The place the dis-

and arrange for one station to act as transmitter and

tortion analyzer ALARM switch to RESET and the

as a receiver. Perform the procedure below and then

DISTORTION SELECTOR to AVERAGE S/M.

reverse roles and repeat the procedure.

(1) Transmitting Circuit. If the local station is to

message "Quick Brown Fox". The receiving station will

act as transmitter, prepare the transmitting circuit

mad the average displacement of the mark-to-space

shown in figure 6-19 and set the AN/GGM-15(V)1

transitions of the input signal as indicated on the per-

test pattern generator controls as follows:

cent distortion meter. If the mark indicator lamp is on,

(a) Use DATAOUTPUT.

marking bias distortion is indicated. If the space indi-

(b) P-N switch to P.

cator lamp is on, spacing bias distortion is indicated.

Record the results.

(d) LEVEL CODE to 5.

(d) Turn power off at both stations.

(e) CHARACTER LENGTH to 7.

(4) Performance Standards. The maximum total

(f) MESSAGE SELECT to MSG.

peak telegraph distortion permissable is 20%. The

(g) BAUD RATE to 75.

maximum mark or space bias distortion permissable is

(2) Receiving Circuit. If the local station is to act

12%.

as receiver, prepare the receiving circuit shown in fig-

Figure 6-19. Station to station total peak and average bias telegraph teat.

6-23