Use the Test Point Compensation (TPC) configuration screen to mathematically
adjust DSAM level readings. This better represents the level value at
a common point of reference, such as adding 10dB automatically to level
readings taken at a 10 dB down tap to better represent the level value
on the main distribution hard line. TPC affects the measurement levels
of most measurement modes on the DSAM. A graphical representation of the
way the user-entered TPC values affect the level readings is available
by pressing Summary softkey while in the configuration mode. TPC values
are saved inside of each saved measurement file and permanently associated
with the file.
Test Point Compensation will display an icon in each of the modes it applies
to. If a mode is created that has a total effect of 0 dB on the current
mode, the icon will not be displayed (Default Settings has an effect of
0 dB). The total effect of the current Test Point Compensation file (if
non-zero) is displayed to the right of the icon. The Test Point Compensation
configuration screen can be reached within each of these modes by pressing
the keypad shortcut of shift-4. When the user is finished with the Test
Point Compensation configuration, press Done to return to the original
measurement mode.
Test Point Compensation applies to the following modes:
- Level
- Miniscan
- Full Scan
- Tilt
- Constellation
- DOCSIS Range (downstream results only)
- Upstream Spectrum
- Downstream Spectrum
- Ingress Resistance
- Forward Sweep
- Reverse Sweep
- Combo AutoTest
- Video AutoTest
- CM AutoTest
-
NOTE: Forward TPC values are applied to all modes except Reverse
Sweep. Reverse TPC values are applied to only the Reverse Sweep mode.
The main Test Point Compensation (TPC) screen contains a listing of TPC
files. TPC files can be created from this screen or deployed to the meter
via the JDSU Test Productivity Pack software. Each file displays the reverse
and forward compensation to the right of its name. Files can be created,
edited, and deleted. Select files by using the up and down keys.
The "edit TPC Plan" screen provides the following settings.
REVERSE:
Internal Loss (dB)
Example: Attenuation pad within an amplifier under test
The range is -50.0 to 50.0 dB and the default value is "0.0 dB".
External Loss (dB)
Example: A distribution tap value on a drop
The range is -50.0 to 50.0 dB and the default value is "0.0 dB".
Probe Loss (dB)
Example: Attenuator added inline with test lead
The range is -50.0 to 50.0 dB and the default value is "0.0 dB".
NOTE: The sum of the Internal,
External, and Probe loss
values is restricted to a minimum of -100 dB and a maximum of +100 dB.
Reverse Telemetry Level
The range is 10 to 55 dBmV and the default value is "20 dBmV".
Reverse Sweep Insertion Level
The range is 10 to 55 dBmV and the default value is "20 dBmV".
FORWARD:
External Loss (dB)
Example: A distribution tap value on a drop
The range is -50.0 to 50.0 dB and the default value is "0.0 dB".
Probe Loss (dB)
Example: Attenuator added inline with test lead
The range is -50.0 to 50.0 dB and the default value is "0.0 dB".
Use the arrow keys to highlight the item you want to edit on the configuration
screen. Press ENTER to open the edit box and use the alphanumeric
keypad to type your entry or the arrow keys to select the choice you prefer.
Then press ENTER to complete the edit.
Test Point Compensation menu options include:
FILE:
Allows you to create a NEW file,
RENAME an existing file, or DELETE an existing file. NOTE:
If the "OFF" TPC file is selected, the RENAME
and DELETE menu items are unavailable.
EDIT:
Allows you to edit the forward and reverse parameters. NOTE:
This button is unavailable if the "OFF" TPC file is selected.
SUMMARY:
Displays a graphical representation of the user-entered TPC values for
the selected TPC file.
DONE:
Activates the currently selected file and closes the mode