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hspice用的hspice_Z-2007.03_Win版,看了手册里面的说明,
感觉还是搞不清楚。哪位牛人能给帮助解析一下。
测试了如下3个简单例子,发现它们在0时刻的值不一样外,
后面的值都是一样的。
vs 1 0 dc 5v
r1 1 2 1k
c1 2 0 1u ic=1v
.tran 1n 1u
.print v(2) i(r1)
**************************************
time voltage current
2 r1
0. 5.0000 0.
1.00000n 1.0000 4.0000m
**************************************
vs 1 0 dc 5v
r1 1 2 1k
c1 2 0 1u ic=1v
.tran 1n 1u uic
.print v(2) i(r1)
**************************************
time voltage current
2 r1
0. 0. 0.
1.00000n 1.0000 4.0000m
**************************************
vs 1 0 dc 5v
r1 1 2 1k
c1 2 0 1u
.ic v(2) = 1v
.tran 1n 1u uic
.print v(2) i(r1)
**************************************
time voltage current
2 r1
0. 1.0000 0.
1.00000n 1.0000 4.0000m
**************************************
而如下的例子,除0时刻的值与上面的不一样外,
后面的部分时间点的数据不完全一致,有较小的差别。
vs 1 0 dc 5v
r1 1 2 1k
c1 2 0 1u
.ic v(2) = 1v
.tran 1n 1u
.print v(2) i(r1)
**************************************
time voltage current
2 r1
0. 1.0000 4.0000m
1.00000n 1.0000 4.0000m
**************************************
附手册上的说明:
Use this command(指.IC) to set transient initial conditions in HSPICE RF. How it initializes depends on whether the .TRAN analysis statement includes the UIC parameter. In HSPICE RF, .IC is always set to OFF.
If you specify the UIC parameter in the .TRAN statement, HSPICE RF does not calculate the initial DC operating point, but directly enters transient analysis. Transient analysis uses the .IC initialization values as part of the solution for timepoint zero (calculating the zero timepoint applies a fixed equivalent voltage source). The .IC statement is equivalent to specifying the IC parameter on each element statement, but is more convenient. You can still specify the IC parameter, but it does not have precedence over values set in the .IC statement.
If you do not specify the UIC parameter in the .TRAN statement, HSPICE RF computes the DC operating point solution before the transient analysis. The node voltages that you specify in the .IC statement are fixed to determine the DC operating point. HSPICE RF does not output node voltage from operating point (.OP) if time (t) < 0. Transient analysis releases the initialized nodes to calculate the second and later time points. |
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