R&S 1129.7246.03, Operating Manual

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Operating Manual 1302.6163.12 - 03 4.97
R&S ESU Instrument Functions
APD Mode
Fig. 4.30 Zero span of a pulsed signal (single or low PRF)
Fig. 4.31 APD of a pulsed signal (single or low PRF)
Next, let us consider the case that the repetition frequency of the impulse increases
as shown in
Fig. 4.32 . The disturbance shown in Fig. 4.32 has a higher average
value than Fig. 4.30 because of the increasing pulse repetition frequency, but the
log-average value (X
avg
) of Fig. 4.32 does not show any difference from that of Fig.
4.30 . This is because the log-average value mainly depends on the receiver noise
and strongly suppresses impulsive noise in this case. But the APD of the distur-
bance, shown in
Fig. 4.33 , has high sensitivity to variation in the average value.
Clearly the probability presented in Fig. 4.33 increases when compared with Fig.
4.31 .