Equalization (DVB-S2/S2X)

The Equalization parameter group configures the measurement controls that relate to equalization.

Equalization Mode determines which mode to use when estimating the best possible equalizing FIR Finite Impulse Response filter taps that will compensate for variations in the IF.

Least Mean Squares - equalization filter will minimize the mean square error at the symbol decision points or for the entire error vector.
XCorrelation - the equalization impulse response is updated by the cross correlation between the error vector and the input data. When XCorrelation is selected, a Reset button appears to the right of the EQ Tracking parameter to allow resetting the adaptive equalization coefficients as a single point impulse response for the carriers.

Default: Least Mean Squares

Choices: Least Mean Squares, XCorrelation

Channel Estimation Source determines which fields are used to estimate the frequency response of the channel.

None - No equalization is applied to the frame.
Pilots - Pilots are used to estimate the channel for equalization.
SOF, Pilots, and Data - Start of Frame (SOF), Pilots, and Data allocations are used to estimate the channel for equalization.

Default: None

Choices: None; Pilots; SOF, Pilots, and Data

Normalized Channel Delay Spread sets the expected delay spread of the channel in units of symbols. The actual equalization filter length is 2 * Normalized Channel Delay Spread + 1.

Default: 5 symbols

EQ Tracking determines which impairments are tracked for equalization impulse response.

Off - there is no tracking for equalization impulse response, so the equalization impulse response is re-calculated for each run.
Track - (only available when Equalization Mode is set to XCorrelation) the equalization impulse response is updated run by run. When Track is selected, the Reset button is enabled
Hold - the equalization impulse response is held to the most recent equalization impulse response estimate.

Default: Off (Track when Equalization Mode is set to XCorrelation)

Choices: Off, Track, Hold

Reset (only available when Equalization Mode is set to XCorrelation) resets the adaptive equalization coefficients as a single point impulse response for the carriers. This makes the initial estimate transparent, causing no frequency response shaping to the channel.

Tracking Convergence (only available when Equalization Mode is set to XCorrelation) controls the rate of convergence of the adaptive equalizer of the digital demodulation measurement. Convergence determines how quickly the equalization filter coefficients converge to the estimated values for each measurement. Larger values converge faster but might not be as consistent, based on noise in the data. Smaller values converge more slowly but provide a more consistent equalization filter for a given channel. This provides a trade-off in the number of measurements required for convergence of the equalization filter taps, and the stability of those taps. For more information, see Convergence (Digital Demod).

Default: 1E-06