Chapter 7
DS0 VF Test Commands
Description of VF test commands
74
CT-650 Command-Line Reference Guide
Release 9.4
Intermodu-
lation distor-
tion
Intermod_Dist
Measures the second and third harmonics of a
test signal. To measure the harmonics, the
CT-650 uses a test tone that comprises four
equal-level tones. Two of the tones are centered
at 858.95 Hz and are 53 Hz apart; the other two
tones are centered at 1379.1 Hz and are 10.7
Hz apart. The test uses narrow band filters at
520 Hz and 2240 Hz. The average of these two
values is the second-order distortion. A narrow-
band filter at 1900 Hz measures the third-order
distortion. The values are expressed in dB
below the received signal. Before sending the
four test tones, the CT-650 measures the noise
in the filters. This value is subtracted from the
four-tone power measurements to ensure accu-
rate values for the second and third order distor-
tion.
Line tran-
sients
Line_Transient
Measures gain hits, phase hits, and dropouts
that occur in a high-speed data circuit. A gain hit
is a rapid change in the level of the signal and is
usually accompanied by a phase hit. A phase hit
is a rapid change in the phase of the signal. A
dropout is a rapid loss in the signal level usually
greater than 12 dB for 4 milliseconds. These
types of line transients can disrupt high-speed
data circuits, and are primarily caused by
switching to standby facilities, radio fades in
microwave paths, and noise transients that
affect carrier equipment. A transient exceeds
the thresholds defined by the user and has a
duration of greater than 4 ms. However, the
CT-650 does not count transients when a drop-
out occurs on the circuit under test. This test is
not available when testing signaling.
Table 4
VF measure tests (Continued)
Test
Syntax
Description
Содержание CT-650
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Страница 104: ...Chapter 7 DS0 VF Test Commands Description of VF test commands 78 CT 650 Command Line Reference Guide Release 9 4 ...
Страница 108: ...Chapter 8 Batch Files Unavailable commands for batch files 82 CT 650 Command Line Reference Guide Release 9 4 ...
Страница 198: ...Appendix A Test Results Definitions Loopback status information 172 CT 650 Command Line Reference Guide Release 9 4 ...
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