Compensation (DVB-S2/S2X)

Compensation contains parameters that compensate for measured signal impairments.

Reference Bits Plane selects the reference bits plane when generating the reference symbols. Reference bits are used to create referrence symbols, which then are used to compute EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format..

Measured at FECFRAME - the reference bits are measured at the FECFrame plane.
Measured at BBHEADER/DATAFIELD - the reference bits are measured at the BBHeader/Datafield plane.
User supplied at BBHEADER/DATAFIELD - the reference bits are supplied by user at the BBHeader/Datafield plane. To select this option, the Payload must not be Unknown or Custom, and BCH/LDPC Encode On must be selected.

Default: Measured at FECFRAME

Choices: Measured at FECFRAME, Measured at BBHEADER/DATAFIELD, User supplied at BBHEADER/DATAFIELD

Frequency Estimation Mode determines whether the frequency error is estimated and compensated. Having an incorrect carrier frequency estimate can lead to significant errors during the demodulation process. The carrier frequency estimate is indicated in the Carrier Aggregation tab, where each component carrier has an absolute center and offset from that center frequency.

Off - There is no frequency error estimation and compensation.
Normal - The frequency error is estimated and compensated during the measurement interval.

Default: Normal

Choices: Off, Normal

Phase Tracking Mode determines how phase tracking and offset is performed.

Off - There is no phase tracking.
Interpolate with Pilot - Phase offset estimation is based on the pilot symbols, after which an interpolation is done between the pilot symbols to get per-symbol phase offset, which is then compensated, symbol by symbol. When Interpolate with Pilot is selected, the Phase Tracking Interpolation Mode is enabled to choose the interpolation method.
Moving Average Over All - Phase offset for symbols (pilot and data) is calculated, then a moving average is done for this phase offset. The moving filter length is decided by the Phase Tracking Filter BW parameter.

Default: Off

Choices: Off, Interpolate with Pilot, Moving Average Over All

Phase Tracking Interpolation Mode (enabled when Phase Tracking Mode is set to Interpolate with Pilot) determines the type of interpolation used.

Average And Nearest - Average the phase offset on the contiguous pilot symbols, then use that averaged value for the nearest pilot and data symbols.
Linear Interpolation - Linear interpolation on all data symbols with the phase offsets on all pilot symbols.

Default: Average And Nearest

Choices: Average And Nearest, Linear Interpolation

Phase Tracking Filter BW (enabled when Phase Tracking Mode is set to Moving Average Over All) determines the moving filter length (bandwidth) by multiplying the value entered in this field by the Symbol Rate.

Default: 0.01

Compensate Symbol Clock Error enables or disables compensation for measured symbol clock error.

Enabled - Compensation for measured symbol clock error is applied to the signal.
Disabled - No symbol clock error compensation is applied to the signal.

Default: Disabled

Range: Enabled, Disabled

Compensate IQ Offset enables or disables compensation for measured IQ offset.

Enabled - Compensation for measured IQ offset is applied to the signal.
Disabled - No IQ offset compensation is applied to the signal.

Default: Enabled

Range: Enabled, Disabled

Compensate IQ Gain Imbalance enables or disables compensation for measured IQ imbalance.

Enabled - Compensation for measured IQ imbalance is applied to the signal.
Disabled - No IQ imbalance compensation is applied to the signal.

Default: Disabled

Range: Enabled, Disabled

Use Multicarrier Filter specifies whether to apply a filter to the carrier to filter out adjacent carriers.

Enabled - When other carriers are expected to be adjacent to the DVB-S2/S2X carrier of interest, this multicarrier filter can be used to filter out the unwanted carriers and minimize leakage into the DVB-S2/S2X carrier of interest.
The multicarrier filter for a carrier is designed to have a default passband of (1+alpha)*SymbolRate and a stopband of either 2*SymbolRate, or halfway between the carrier and the closest adjacent carrier, whichever results in a narrower stopband. It is possible that the filter cannot be designed based on the constraints (carriers too close together). In this case, the multicarrier filter will not be applied to the carrier.
Disabled - No multicarrier filter is applied to the carrier.

Default: Disabled

Range: Enabled, Disabled