User guide

Syntax
set_instance_assignment -name XCVR_A10_RX_ADP_VGA_SEL <value> -to <rx_serial_data pin
name>
Decision Feedback Equalizer (DFE) Settings
The decision feedback equalizer (DFE) amplifies the high frequency component of a signal without
amplifying the noise content. The DFE removes the post-cursor Inter Symbol Interference (ISI) of the bits
received previously from the current bit and improves the Bit Error Rate (BER). The DFE architecture
supports seven fixed taps and four floating taps. The fixed taps in DFE remove the ISI of the previous 7
bits from the current bit.
The DFE circuit stores delayed versions of the data. The stored bit is multiplied by a coefficient and then
summed with the incoming signal. The polarity of each coefficient is programmable.
Note: The DFE fixed tap assignments are described in the following section.
XCVR_A10_RX_ADP_DFE_FXTAP
Description
The following assignments specify the coefficient of DFE fixed taps 1 through 7. Use these assignments
only when the DFE is enabled and adaptation is disabled for the DFE (DFE operates in manual mode).
The default value for all assignments is set to RADP_DFE_FXTAP<1 to 7>_0 for DFE fixed tap<1 to 7>
coefficient setting 0.
Table 8-11: DFE Fixed Tap Assignments
Assignment Pin Planner or
Assignment Editor
Name
Value Description
XCVR_A10_RX_
ADP_DFE_
FXTAP1
Receiver Decision
Feedback Equalizer
Fixed Tap One
Coefficient.
RADP_DFE_
FXTAP1_<0 to 127>
DFE fixed tap 1 Coefficient Setting
<0 to 127>
XCVR_A10_RX_
ADP_DFE_
FXTAP2
Receiver Decision
Feedback Equalizer
Fixed Tap Two
Coefficient.
RADP_DFE_
FXTAP2_<0 to 127>
DFE fixed tap 2 Coefficient Setting
< 0 to 127>
XCVR_A10_RX_
ADP_DFE_
FXTAP3
Receiver Decision
Feedback Equalizer
Fixed Tap Three
Coefficient.
RADP_DFE_
FXTAP3_<0 to 127>
DFE fixed tap 3 Coefficient Setting
<0 to 127>
XCVR_A10_RX_
ADP_DFE_
FXTAP4
Receiver Decision
Feedback Equalizer
Fixed Tap Four
Coefficient.
RADP_DFE_
FXTAP4_<0 to 63>
DFE fixed tap 4 Coefficient Setting
<0 to 63>
8-10
Decision Feedback Equalizer (DFE) Settings
UG-01143
2015.05.11
Altera Corporation
Analog Parameter Settings
Send Feedback