Programmable De-Emphasis - Intel Agilex User Manual

2. Intel Agilex I/O Features and Usage
UG-20214 | 2019.04.02
unlike the overshoot caused by signal reflection. The amount of pre-emphasis required
depends on the attenuation of the high-frequency component along the transmission
line.
Figure 3. Programmable Pre-Emphasis
This figure shows the true differential output with pre-emphasis.
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2.2.7. Programmable De-Emphasis

The programmable de-emphasis feature is supported for all voltage-reference I/O
standards. This feature supports a two-taps de-emphasis implementation, which
consists of a main tap and a 1-UI delayed post tap.
When using this feature, the height of the I/O signal is attenuated whenever a symbol
is longer than one UI. This feature supports two types of de-emphasis:
• Constant impedance—available for single-ended and differential SSTL-12,
HSTL-12, and HSUL-12 I/O standards.
• Low power (non-constant impedance)—available for single-ended and differential
SSTL-12, HSTL-12, HSUL-12, and POD12 I/O standards.
Each of the de-emphasis has three equalization settings - low, medium, and high.
Constant impedance de-emphasis has double effective equalization level of the low
power de-emphasis.
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Voltage boost
from pre-emphasis
V
V
P
P
V
OD
Differential output
voltage (peak–peak)
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Intel Agilex General Purpose I/O and LVDS SERDES User Guide
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