EXFO CableSHARK P3 VF/DSL Cable Qualifier - Manual (Page 114)

VF / DSL Cable Qualifier
102
Press the RUN / STOP button on the front of the CableSHARK to initiate the test.
Figure 8.3.3A shows an example of the results obtained from an ADSL2+ Test
0 555 1106 2200 kHz 1657
MAIN
MENU
E CHG
DMT TEST RESULT
TEST
SETU P
Single end D MT test complete.
SHOW
REF
Cursor Tone/Freq
Tone Level
Noise Level
S/N R atio 127 / 547.687 kH z
-5 3.32 dBm/H z
-1 32.28 dBm/ Hz
80.4 dB Num ber Of Bits
Upstream Ra te
Dow nstream Rate
Noise Margin Up/D own 11
1024 kbps
2302 4 kb ps
6 / 7
-1 0
-2 0
-3 0
-4 0
-5 0
-6 0
-7 0
-8 0
-9 0
-1 00
-110
-1 20
-4 6
-5 6
-6 6
-7 6
-8 6
-9 6
-1 06
-116
-1 26
-1 36
-1 46
-1 56
dBm/to ne dBm/H z
=
=
=
= =
=
=
=
F
SAVE/
UPLOAD ZOOM IN
HORI Z
EXTR APOL ATED ADSL2+ ITU Ann ex A/POTS R ATES
PROBABLE SIGNAL - AD SL U p
F IGURE 8.3.3A – ADSL2+ D ATA R ATE P REDICTION T EST
The ADSL2 / ADSL2+ Data Rate Prediction test looks at the attenuation of the ATU PSD Mask rather than
the simple frequency response of the original DMT test. This process provides a more accurate estimation of
the data rate expected by the customer.
Here are the PSD masks for ATU-R (CPE) and ATU-C (CO). The transmit level of the signal will depend
upon the length of the circuit under test. For short lengths, a low transmit level will be used to prevent
unnecessary crosstalk in adjacent pairs. For long lengths, a higher transmit level will be used to allow the
signal to reach the far end.