:SPRocess:PFIT:DISPlay

Command Syntax

:SPRocessN:PFIT:DISPlay {PRESponse | SRESponse | FWAVeform}

<cutoff_frequency> is a double.

Where N identifies one of up to 64 possible operators {1:64} that can be defined as part of a math function. The operators are numbered in the order that they were originally added to the function.

Query Syntax

:SPRocessN:PFIT:DISPlay?

Description

Specifies the display mode of a Pulse Fit filter operator (:FUNCtion:FOPerator PFIT). Display mode determines the algorithm that Pulse Fit uses to model the system pulse response waveform. To specify the filter's pulse delay (Dp), use the :SPRocess:PFIT:DELay command. To specify the filter's pulse length (Np), use the :SPRocess:PFIT:LENGth command.

PRESponse (Pulse Response)

Pulse Fit determines the pulse response waveform from the characteristics of the pseudo-random input pattern which is treated as a series of pulses having different polarities and amplitudes. The pulse fit operator uses the entire pattern and the pulse response is modeled (repeats) at the repetition rate of the pattern. This allows signal processing (for example, CTLE and linear equalization) on the response waveform. This is the default setting.

SRESponse (Step Response)

Step Response fits the pattern to a step waveform.

FWAVeform (Fit Waveform)

Fit Waveform allows you to view how well the pulse response models the actual behavior of your waveform. Fit Waveform converts the pulse response back to the ideal input waveform which should closely match the original waveform.

The following figures compare how the Display Mode settings result in different response waveforms. An additional picture shows the Fit Waveform's error waveform which results from adding a Subtract operator to the Pulse Fit Operator. In these pictures, the red trace is the input pattern and the green waveform is the output response.

Display Mode Waveforms

Pulse Response	Step Response	Fit Waveform

Example Command Sequence

:FUNCtion2:FOPerator PFIT
:SPRocess2:PFIT:DISPlay PRESponse 
:SPRocess2:PFIT:DELay 3
:SPRocess2:PFIT:LENGth 200
:SPRocess2:PFIT:ZPAD OFF
:FUNCtion2:DISPlay ON