On the Threshold Performance of a PCM/FM Receiver

Studies for the Skylab PCM links reveal that for a binary PCM/FM communication receiving system with a rectangular predetection bandpass filter, an ideal limiter discriminator and an ideal integrate-and-dump postdetection filter, suboptimal system performance can be achieved by choosing the largest possible value of deviation index which lies approximately at
0.7 + 2n
, where
n = 0,1,.. ,k
. The upper limit
k
of
n
is partially determined by the reconstructability of the PCM signal after passing through the bandpass filter. Experimental data support favorably the theoretical result.