急，请教高手达人，怎么用spectre仿真高速D触发器的眼图？

最近我设计了一款高速的DFF，速率可以达到1GHz,
跑完spectre tran仿真后，
出现了还算可以的波形信号，于是就直接调用scanwave中的caculator工具中的
eyediagram函数，设定begin time 为“0”，end time 为tran仿真结束时间，
period 设定为 “100p” 然后plot。
可得不到像样的眼图，请教高人如何进行此类数字电路的眼图仿真?
ps：输入输出信号为单级NRZ数字信号（如 1V-2V）

eyeDiagram
eyeDiagram ( o_waveform n_start n_stop n_period ?advOptions t_advOptions )
=> o_waveform/nil

Description
Returns an eye-diagram plot of the input waveform signal. It returns the waveform object of the eye-diagram plot. Using an advanced option, the function also calculates the maximum vertical and horizontal opening of the eye formed when the input waveform is folded by the specified period to form the eye.
Arguments
o_waveformInput waveform signal.
n_startThe X-axis start value from where the eye-diagram plot is to begin.
n_stopThe X-axis stop value where the eye-diagram plot is to terminate.
n_periodThe period after which the waveform is to be folded to form the eye.
t_advOptionsThe option to specify whether the vertical or horizontal opening of the eye is to be calculated.
Valid values: vertical, horizontal
Default value: nil
Note:If t_advOptions is specified, the function approximates vertical eye height and horizontal eye width to assume the symmetry of the eye. The function returns the most optimum results for single eye scenarios.
Value Returned
o_waveformReturns a waveform object representing the eye-diagram plot of the input waveform
nilReturns nil and an error message otherwise
Example
eyeDiagram( v("/out" ) 0n 500n 12.5n )
Returns a waveform that represents an eye-diagram plot.
eyeDiagram( v("/out" ) 0n 500n 12.5n ?advOptions "vertical" )
Calculates the maximum vertical opening of the eye that is formed when the input waveform is folded after 12.5n
eyeDiagram( v("/out" ) 0n 500n 12.5n ?advOptions "horizontal" )
Calculates the maximum horizontal opening of the eye that is formed when the input waveform is folded after 12.5n

很不错。

很受用！

看不懂