The block diagram arrangements of tests for idle noise and impulse
noise are similar. One difference between the two tests is that the
instantaneous reading of noise peaks in terms of RMS values.
substitution of a "hit" counter for an analog measuring device.
removal of the terminating resistor at the sending end of the
Assume that you want to quote the noise level in terms of dBrnc. You
must place the weighting switch of the TTS-37B on the position marked
Impulse Noise Counter Model TTS-58A (appendix A, section IV, figure 4)
uses LO, MED, and HI counters. Why are MED and HI counters provided
when the total count shows on LO?
The threshold is adjusted so that the noise spectrum is indicated
by the MED and HI counters.
By observing the three counters, the technician can determine the
number of noise peaks in a given time occurring at three
The HI counter is necessary because the number of peaks may be
more numerous than the LO counter can indicate.
MED and HI counters are needed
occurrence of the noise peaks.