EXFO CableSHARK P3 VF/DSL Cable Qualifier - Manual (Page 112)

VF / DSL Cable Qualifier
100
noise floor on potential data rate. A 'bit/bin' graph showing a relatively filled in box will indicate a cable that is
capable of transmitting / receiving at very high data rates.
Use the Cursor Pad LEFT/RIGHT arrow keys to move the cursor from left to right and back on the screen.
The cursor position indicates Cursor Tone, Cursor Frequency, Tone Level, Noise Level, and number of
bits/bin, etc..
Interference from radio transmission towers can be seen affecting the DMT line coding even though they
only occupy a very small bandwidth. Figure 8.3.2B shows the test result on a cable with G.Lite / POTS
selected as Rx ADSL Evaluation.
MAIN
MENU
E CHG
TEST
SETUP
Single end DMT test complete (for 3971 ft) CPE
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-46
-56
-66
-76
-86
-96
-106
-116
-126
-136
-146
-156
dBm/tone dBm/Hz
4 141 278 552 kHz 415
F
SHOW
REF ZOOM IN
HORIZ
EXTRAPOLATED G.LITE / POTS RATES
PROBABLE SIGNAL - undetermined
Cursor Tone/Freq
Tone Level
Noise Level
S/N Ratio
63 / 271.687 kHz
-57.32 dBm/Hz
-132.28 dBm/Hz
74.96 dB
Number Of Bits
Upstream Rate
Downstream Rate
Noise Margin Up/Down
8
512 kbps
1856 kbps
20 / 24
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SAVE/
UPLOAD
F IGURE 8.3.2B - R ESULTS OF A G.L ITE T EST
At the completion of a test, the function button command selection at the bottom of the DMT Test Result
screen consists of seven options available to the operator. The following are brief descriptions of each of the
Function button options:
SHOW REF Pressing the function button corresponding to SHOW REF allows a user to
overlay a REFERENCE MASK over the test result on screen to compare the
two. See Section 5.4 for more information about the REFERENCE MASK
feature.