Newtec MDM9000 - Page 300

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Feature Descriptions
MDM9000 Satellite Modem
Parameter Description
Enable
Enable the bandwidth cancellation.
Expected Round Trip
Delay
Set this to the round trip delay the carrier (that is uplinked, received and
canceled out) will experience. The closer this value is to the actual delay,
the faster the canceling starts.
Set this value to 0 when doing a back-to-back test.
Round Trip Delay
Search Window
Enter the round trip delay search window that the cancellation function
uses to try to acquire full lock.
The advised starting value is set to 20 ms but once the actual round trip
delay is known, the search range can be decreased. This to reduce the
search time and speed up full lock. However, keep some range to allow
for delay due to Doppler effects.
Local Carrier Rx
Freq Offset
Enter the local carrier Rx frequency offset.
0 MHz in this example.
Local Carrier Rx
Freq Search Window
The frequency search window in which the demodulator searches for the
received local carrier. By observing the local carrier center frequency
offset, this value can be decreased to reduce the search time and speed
up full lock.
Local Carrier
Spectral Inversion
In case an upconverter or the satellite transponder inverses the
spectrum of the carrier, the cancellation function needs to re-inverse the
spectrum prior to actual cancellation. In case automatic is used, the
canceler toggles continuously between inverted and direct spectrum.
In order to speed up lock time, observe the detected inversion in the
monitoring parameter "local carrier spectral inversion" and set the
detected inversion here.
Bandwidth Mode This parameter sets the range of parameters of the acquisition loops.
Use the bandwidth mode to balance the search range versus the
acquisition time.
• Normal: Standard settings for the acquisition loops.