Alpha Technologies XP-EDH4 - Technical Manual - Manual (Page 59)

59 745-419-B0-001 Rev. A (11/2013)
3.9.17 RF Constellation Page
Select the RF tab to access the Constellation page. Click the Constellation button to view the
constellation display for DOCSIS channel. The page will automatically refresh until the updates
remaining counter reaches 0. Clicking the Run button restarts the automatic refresh, and clicking
the Stop button stops it.
Fig. 3-18, Constellation Page
3.9.18 Controls
• Run — Start the sampling of data by pushing the Run button. The unit will acquire 100 samples
and then stop.
• Stop — Use the Stop button to end the sampling.
3.9.19 Downstream Data
• Frequency — is the downstream frequency given in mHz.
• Power — is the downstream power given in dBmV.
• SNR / (RxMER) — this is the downstream signal quality. Modulation Error Ratio (SNR)
• EVM —Error Vector Magnitude (from hardware MER (Modulation Error Ratio) / software MER).
• CER Interval — Codeword Error Rate (CER) refresh rate.
• Pre FEC CER — Codeword Error Rate (CER) BEFORE forward error correction is applied.
• Post FEC CER — Codeword Error Rate (CER) AFTER forward error correction is applied.
• Updates Remaining — this is the number of sample updates remaining for this session.
3.0 Configuration and Operation, continued