Altera JNEye User Manual
Page 30
Pre-Emphasis
Select or specify the transmitter pre-emphasis, de-emphasis, or TX-FIR configuration in one of the
following modes:
• Auto—JNEye uses its link optimization algorithm to find the optimal transmitter FIR settings.
• Auto with Manual Starting Point—Specify the initial TX pre-emphasis or FIR configuration. JNEye’s
link optimization engine uses the TX settings as initial conditions.
• Manual—For non-Altera devices, you can manually input the tap coefficients. For Altera devices,
select individual FIR levels from the menus for each FIR tap. The FIR selection for Altera devices is
VOD dependent. Therefore, changing the VOD or device type can reset the TX FIR menu contents.
For a generic transmitter type, a set of typical FIR coefficients is included in the pull-down menu.
• Off
Estimated TX EQ AC Gain
Select pre-tap and post-tap values to estimate the AC gain in dB scale. The TX EQ AC gain is calculated as
the gain between the DC (0 Hz) and the Nyquist frequency of the link, assuming a FIR type of transmitter
pre-emphasis scheme.
Note: This is a rough analytical estimate of TX EQ AC gain that may differ from the actual AC gain
generated by the transmitter.
PLL Type and Bandwidth
Select the type and bandwidth of the PLL used in the transmitter to generate the transmitter clock.
• Ideal Clock—The default PLL setting. The PLL is disabled and the clock is passed from the external
reference clock.
• For Altera transmitters, PLL models and configurations are automatically set based on the following
settings:
• Data rate
• Reference clock frequency
• Oscillator type:
• Stratix V GX and Arria V GZ—ATX (LC) or CMU
• Stratix V GT—ATX (LC)
• Arria 10 GX/SX/GT—ATX (LC), Fractional PLL, or CMU
• PLL bandwidth
• Altera transmitter PLL configurations such as internal divider ratios
Altera recommends that you follow Altera’s reference clock selection and PLL configurations
recommendations when setting up the transmitter PLL. Without following the reference clock and
PLL guidelines, you might operate and simulate an unstable PLL and see unexpected results.
• For Custom transmitters, PLL models and configuration are set automatically based on settings
similar to that of Altera PLLs while more comprehensive PLL configuration capabilities are under
development. With custom transmitters, the VCO can be either LC type or ring oscillator (Ring) type.
More PLL to reference clock divider ratios are supported in the custom PLL type. Follow Altera's PLL
and reference clock guidelines when setting up transmitter PLLs to avoid unexpected results.
• PLL is currently not supported for IBIS-AMI transmitters.
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Transmitter Setting
UG-1146
2015.05.04
Altera Corporation
Functional Description