Figure 3-3. Conversion of analog to digital signals.

TM 11-490-5

Figure 3-3. Conversion of analog to digital signals.

system to interference is a major factor in the error rate

(2) Since interference in a digital system causes

the system can tolerate without total loss of information

errors in the digital bit stream, some method of error

transfer.

detection can be used to monitor system 'performance.

(4) Since the interference does not appear directly

If adequate error correction cannot be provided,

in the audio channel output, the output will not provide

retransmission must be requested, either automatically

reliable information for interference identification.

or manually. In a voice channel these errors can cause

However, the total or composite signal is generally

a change in one or more words with little indication that

present in some form at the receiver detector.

interference is present. In a data channel, erroneous

Therefore, by monitoring this composite signal prior to

data is the result.

pulse detection and restoration. an appropriate display

(3) Most digital systems require some type of time

could be used to detect and identify interference in a

synchronization between the encoder at the transmitting

manner similar to that used in an analog system.

end and the decoder at the receiving end.

The

susceptibility of this synchronization

3-3