The CONSTELLATION mode allows you to:
- view a graphic depiction of the signal,
- view the QAM type (64 or 256),
- view the channel number,
- view the channel frequency level information,
- examine Modulation Error Ratio (MER) and Bit Error Ratio (BER) Pre and
Post data,
- determine the interleave depth parameter for the demodulated QAM carrier
(Annex B only)
- select closer views of impairment with Zoom,
- view the zoom level, and
- edit the number or samples taken per screen refresh.
The CONSTELLATION mode continuously updates the graphic depiction of the
signal along with the MER and BER data.
Softkeys
Four softkeys on the Constellation screen provide the following options:
FILE
Save a completed test. You also can open an existing CONSTELLATION file
to compare previously collected data. Use the arrow keys to choose the
menu item you prefer and press ENTER to make your selection.
VIEW
Use the arrow keys to choose the menu item you prefer and press ENTER
to make your selection.
Select (or deselect) Reset to manually reset the Constellation function.
Select Pause to suspend measurement updates (Keystroke shortcut:
SHIFT 8).
Select Single Channel to view the level measurement screen for a
single channel.
Select DQI to view the DQI measurement
screen.
Select
ZOOM
Select Zoom to examine the constellation in more detail. (Note:
Level of zoom is provided in lower right portion of screen. Zoom:
1 indicates that the entire constellation is displayed with no
zoom applied)
SETTINGS
Use the arrow keys to select Samples or Channel Plans and
press ENTER to make your selection.