DFE Operator (Advanced)

The Advanced tab lets you Specify Pattern Symbol Sequence and enter the input signal's pattern, the equalizer's Clock Delay, Tap Limits, and Threshold Bandwidth.

Specify Pattern Symbol Sequence

Use these settings to specify input waveform's pattern symbol sequence (NRZ or PAM4). You can select to have the pattern automatically detected (default), select from a know standard Known Pattern, or a BERT Pattern File (*.ptrn). Available known patterns are listed in the following table. If you select to import a Pattern File, you can specify if the pattern uses Gray Coding. Gray coding, or reflected binary code, is a coding pattern where successive symbols differ by one binary bit. For example in the case of PAM4, binary bit sequences 00, 01,10, and 11 represent levels 0, 1, 2, and 3.

Standard Pattern Selections

Selection	Format		Command Argument	Description
	NRZ	PAM4
PRBS 7 (127 symbols)	♦	♦	PRBS7	27−1 pseudo-random symbol sequence (127 symbols).
PRBS 7 (128 symbols)	♦	♦	EPRBs7	27 pseudo-random symbol sequence (128 symbols).
PRBS 9 (511 symbols)	♦	♦	PRBS9	29−1 pseudo-random symbol sequence (511 symbols).
PRBS 9 (512 symbols)	♦	♦	EPRBs9	29 pseudo-random symbol sequence (512 symbols).
PRBS 11 (2047 symbols)	♦	♦	PRBS11	211−1 pseudo-random symbol sequence (2,047 symbols).
PRBS 11 (2048 symbols)	♦	♦	EPRBs11	211 pseudo-random symbol sequence (2,048 symbols).
PRBS 13 (8191 symbols)	♦	♦	PRBS13	213−1 pseudo-random symbol sequence (8,191 symbols).
PRBS 13 (8192 symbols)	♦	♦	EPRBs13	213 pseudo-random symbol sequence (8,192 symbols).
PRBS 15 (32767 symbols)	♦	♦	PRBS15	215−1 pseudo-random symbol sequence (32,767 symbols).
PRBS 15 (32768 symbols)	♦	♦	EPRBs15	215 pseudo-random symbol sequence (32,768 symbols).
Linearity (160 symbols)		♦	LPAM4
K28.5 (20 symbols)	♦		K28P5
PRBS9Q (511 symbols)		♦	PRBQ9	PRBS9Q (511 symbols).
PRBS13Q (8191 symbols)		♦	PRBQ13	PRBS13Q (8,191 symbols).
CEI SSPR (32762 symbols)	♦		SSPR
SSPRQ (65535 symbols)		♦	QSSPr	SSPRQ (65,535 symbols).

Clock Delay

Clock Delay to delay the decision point used by the slicer. The decision point is placed directly between the edges, so the edges are delayed by the same amount. The Clock Delay is specified in seconds.

Tap Limits

Tap Limits can be selected as based on maximum, bbmax(n), and minimum, bbmin(n), tap values tap. If the Use Pulse Response Optimization) setting in the dialog's Taps tab is on, you can also select Limit Tap Magnitudes and enter a string of comma separated maximum tap magnitudes, bmax(n).

Threshold Bandwidth

Enter the Threshold Bandwidth to set the cutoff frequency of the Gaussian filter. Auto sets the cutoff frequency equal to the symbol rate. You can also select to Display Thresholds Instead of Signal. This allows you to view the way a hardware DFE works by varying the slicer threshold. The waveform viewed is labeled Operator Threshold Waveform in the Block Diagram of Hardware DFE in this topic.

DFE Input Waveform	DFE Output Waveform