Anywave ATSC 25W Краткое руководство по эксплуатации - Страница 11

Просмотреть онлайн или скачать pdf Краткое руководство по эксплуатации для Передатчик Anywave ATSC 25W. Anywave ATSC 25W 13 страниц. Dtv transmitter

8. Check the SNR and Shoulder (LIMD and UIMD) RF performance of your

system on the Exciter hi level status screen as shown below. Linear and Non-

Linear corrections were already performed and optimized at a TPO of 30W

(after the BPF) in the factory and so the stored correction coefficients should

produce good results.

If you are operating at a TPO less than 30W and wish to rerun corrections, please

proceed with the following steps, otherwise please skip ahead to step 12.

9. (Optional Step - Rerunning Corrections) If you are operating at reduced power

and wish to rerun corrections to achieve better performance, you may now

perform Linear and Non-Linear corrections. (Please refer to the Exciter User

Manual for detailed instructions on running corrections). Before running

corrections, it is important to verify proper feedback signal levels. There are two

feedback signal samples used to compute corrections. "RF IN A" (After BPF)

is used to calculate Linear correction coefficients while "RF IN B" (Before BPF)

is used to compute the Non-Linear correction coefficients.

10. (Optional Step) Navigate to the Exciter "DPD" submenu in the Advanced User

menu (simultaneously press Left and Right buttons, then simultaneously press

UP and Down buttons). Be sure the value of Feedback Sample Signal Input

(FSSI) for both A (after) and B (before) reads somewhere between 45% and 75%

- which roughly corresponds to a value of -15 to -5 dBm as measured on a power

meter (note: the FSSI indicator toggles between A and B and will "flash" when

the signal level is out of range, too high or too low). Add or remove the

appropriate attenuator padding to achieve feedback signal levels in the desired

range. Note the AFTER filter feedback sample is used to compute the SNR and

Shoulder Metrics displayed.

11. (Optional Step) Navigate to the Exciter "SYSTEM" submenu and select

UPDATE under ADPC to run corrections. The exciter will then proceed through

4 stages of correction, computing Linear and Non-Linear corrections, and

automatically saving the coefficients into non-volatile memory upon

completion. The correction process typically takes from 8-10 minutes to

complete while real-time performance metrics of SNR and Shoulder

performance are displayed on the LCD.

ACT-25-QSG-DOC-V1.2, 09/29/2014

ATSC 25W TX Quick Start Guide

Page 11 of 13