Chapter 7
DS0 VF Test Commands
Description of VF test commands
72
CT-650 Command-Line Reference Guide
Release 9.4
3 kHz notch
noise
3k_Notch
Measures noise with a 1004 Hz holding tone
(typically at -16 dBm, assuming a 0 dB TLP)
applied at the circuit's originating point. This test
provides a measure of the noise encountered
by a continuous data signal, because the hold-
ing tone activates the channel equipment that
can create noise. Results range from 20 dBrn to
70 dBrn.
Attenuation
distortion
Atten_Dist
>
>
>
>
Measures the difference between the loss of a
transmitted 1004 Hz holding tone versus the
loss of a tone transmitted at a measurement fre-
quency. Once the loss of the holding tone has
been established, the unit compares the loss of
the measurement frequencies (typical range
from 300 to 3500 Hz) to the holding tone to cre-
ate an Attenuation Distortion table or curve con-
taining 30 measurements. This measurement is
limited to 30 start to stop frequency measure-
ments. The test does not test within the range
from 2500 Hz to 2700 Hz to avoid interfering
with in-band signaling.
C-Message
noise
C_Message_Noise
Measures the unwanted noise on an idle chan-
nel using a digital filter that is C-Message
weighted. The measurements on an idle chan-
nel are taken and the results are expressed in
dBrnC, ranging from 10 to 90 dBrnC. If the C-
Message Noise is outside the range of 10 to 90
dBrnC, the system indicates whether the value
is less than 10 or greater than 90 dBrnC.
C-notch
noise
C_Notch_Noise
Measures the unwanted power on a channel.
Specifically, the test measures the C-Notch
Noise level (dBrnC) and the Signal-to-Noise
(S/N) ratio (dB). If the C-Notch Noise level is
less than 10 dBrnC or greater than 90 dBrnC,
the CT-650 indicates that the value is out of
range. A holding tone of 1004 Hz is required to
perform this test.
Table 4
VF measure tests (Continued)
Test
Syntax
Description
Summary of Contents for CT-650
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