Newtec Proprietary
Confidentiality: Unrestricted
R3.2_v1.0
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Feature Descriptions
MDM9000 Satellite Modem
Parameter Description
Enable
Enable or disable 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 will start. Set this value to 0 when doing a
back-to-back test.
A typical value is 240 ms.
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
In most cases this parameter can be set to 0 MHz.
Because most use cases are symmetrical links where the transmission
between hub and remote site are the same.
In non symmetrical use cases the carrier that we wish to cancel can have
a different frequency than the carrier we want to receive.
The demodulator sees two carriers at its input:
• Remote Carrier: The carrier we whish to receive (this is the
demodulator input frequency). This frequency is called the remote
since it is sent by another modem.
• Local Carrier: The carrier sent by this modem and also received by
this modem. Its receive frequency can be different than the frequency
of the remote carrier. The difference between both is the local carrier
center frequency offset.
This is indicated in the following figure:
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