P/Ar (Peak To Average Ratio); Principles - HP 4934A Operating And Calibration Manual

P/AR (Peak to Average Ratio)
Principles
P/AR is a good quick measure of the combined effect of impairments which
produce intersymbol interference on a data signal (for example, phase/delay
distortion, attenuation distortion, intermodulation distortion and noise).
P/AR cannot determine which impairment is causing the problem - its value
is primarily as a benchmark measurement to show up degradations with time
in the transmission quality of a line.
A deviation of more than 4 P/AR units from the benchmark value usually
indicates that some characteristic of the channel has changed significantly.
KEY
FREQUENCY KEY FREQUENCY
A 140.625 Hz 2140.825 Hs
B 380.825 J 2390.625
0 640.626 K 2640.625
D S80.625 L 2890.625
E
114!J.@?.S
M 3140.625
F
13S0.625
N
3380,825
e 1640.626 0 3S40.625
H 1SS0.62S P -369D.«?.6
ABCDEP<3M!JKLMNOP
300 2000 3000
FREQUENCY
Wt)
P/AR SPECTRUM
Making Measurements 2-21