AMERITEC AM-48 - Notched Impulse Noise; Phase Hits; Gain Hits; Dropouts

Measurements (18-0015) AM-48 Test Set
0015-S088-12
8.12 Notched Impulse Noise
This test is the same as the Idle Channel Impulse Noise Test, ¶8.9,
except that it is made over an
active line with a holding tone which is
notched out before the measurements are performed.
8.13 Phase Hits
A phase hit is a sudden change in the phase of the modulation of a
Holding Tone. A threshold of from 5 to 45 degrees is set, and the
number of phase hits that exceed that threshold during the timed
study is counted.
8.14 Gain Hits
A gain hit is a sudden change in the amplitude of the modulation of a
Holding Tone. A threshold of 2, 3, 4, or 6 dB is set, and the number
of gain hits that exceed that threshold during the timed study is
counted.
8.15 Dropouts
A dropout is the loss of the Holding Tone. The number of losses of
the Holding Tone during a timed study is counted. A “loss” of the
Holding Tone occurs if the Holding Tone level and/or frequency go
out of the acceptable range for valid transient measurements.