Config: Comp) Decompression; Config:) Dpd (Dynamic Predistortion); Config: Dpd) Mode; Config: Dpd) Min / Max Search Delay - Comtech EF Data CDM-760 Installation And Operation Manual

Front Panel Operation
CDM-760 Advanced High-Speed Trunking Modem
Use the  arrow keys to set Compression as Enabled or Disabled. Press ENTER.
When Compression is Enabled, ALL traffic on all active ports and all active PIIC interfaces will be
routed through the compression card and will be compressed. The Tx side of the modem will be
symbol rate-limited by the lesser of the FAST-activated Tx or Tx compression symbol rate. All
other FAST Options (e.g., CnC data rate) will still apply.

6.2.2.6.2 (CONFIG: Comp) Decompression

Decompression enables or disables the Rx decompression path (Satellite to LAN). Rx
decompression is not a FAST Option, and it does not require activation with a FAST Access Code.
Use the  arrow keys to set Decompression as Enabled or Disabled. Press ENTER.
When Decompression is Enabled, Rx decompression works at all data rates regardless of the
FAST-activated Tx compression. The decompression setting must match the far side CDM-760 Tx
compression setting. A mismatch causes all data to be dropped.
6.2.2.7

(CONFIG:) DPD (DYNAMIC PREDISTORTION)

Appendix L. DYNAMIC PREDISTORTION (DPD) OPTION
DPD: Mode:Off
MaxSearchDelay:290 ms
Use the   arrow keys to select a parameter. Press ENTER.

6.2.2.7.1 (CONFIG: DPD) Mode

DPD operation requires installation of the DoubleTalk Carrier-in-Carrier module. With
no module installed, DPD Mode is forced Off and this submenu is inoperable. You
must also purchase the DPD FAST option.
Use the arrow keys to select CnC operation as Off or On. Press ENTER.

6.2.2.7.2 (CONFIG: DPD) Min / Max Search Delay

To reduce the time taken for the predistorter to fully converge, you can restrict the range of
delay the search uses. Factory default values for satellite operation are set to a minimum of 230
ms and a maximum of 290 ms. Once DPD has found the exact delay, the value can be further
reduced, but care should be taken to allow sufficient range to accommodate changes in path
delay due to Doppler.
MinSearchDelay:230 ms
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