AMERITEC AM-48 - Figure 8-2. Impulse Noise Thresholds and Blanking Intervals

Measurements (18-0015) AM-48 Test Set
0015-S088-10
Blanking Interval . The blanking interval for a threshold is started
when a pulse exceeds the threshold for the first time. The noise pulse
counter does not count during the blanking interval. The purpose of
the blanking interval is to minimize the affect of ringing on the count.
Without the blanking interval, several counts could be made
immediately after the first pulse, due to secondary pulses caused by
ringing. The blanking interval allows time for the ringing to die
down.
Figure 8-2 illustrates example parameters and shows how the
blanking intervals are initiated.
NOISE SPIKE EXCEEDING
MIDDLE THRESHOLD
THRESHOLDS
LOW THRESHOLD BLANKING INTERVAL
MIDDLE THRESHOLD BLANKING INTERVAL
HIGH THRESHOLD BLANKING INTERVAL
125 ms
HIGH
MIDDLE
AVERAGE
NOISE
LOW
84 dBrn*
82 dBrn*
80 dBrn*
67 dBrn*
DELTA = 2 dB
DELTA = 2 dB
125 ms
125 ms
1
2
2
3
1
3
Figure 8-2. Impulse Noise Thresholds and Blanking Intervals