004_dot_vec : .VEC statement use
Requires: SmartSpice & Smartview
Minimum Versions: SMARTSPICE 3.16.12.R
This example illustrates the AC magnitude response of the 2-pole Chebyshev Low Pass Filter schematic. The example uses the JFET-based LF356 operational amplifier. The Chebyshev magnitude response in db is shown from the magnitude.png waveforms screenshot to change as the poles of the filter are changed.
There are several ways to do this in SPICE, but a common method is to use a form of parametric analysis. In this example, the .ST statement is used to modify the capacitance value of C1 which is increased from 0.8uF to 1.2uF in steps of 0.1uF. The five magnitude responses from these values can be seen in the plot.
Input Files
DotVecIOSources.in
* TEST Vec file for input/output sources with parameters -
* slope, tris/tfall, period, t(o)delay vih/vil, vth, vol/voh
***** Circuit description
*****************************
r node 0 1
*******************************************************************
* .VEC WITH RIGHT FILENAME
********************************************************************
.Vec "DotVecIOSources.vec"
.TRAN 0.1ns 40ns
.PRINT v(node)
.options nomod
.END
DotVecIOSources.vec
; TEST Vec file for input/output sources with parameters - slope, tris/tfall, period, t(o)delay vih/vil, vth, vol/voh radix 11 io io tunit ns slope 0.6 0 1 trise 0.2 10 tfall 0.7 01 period 3 tdelay 10 vih 1.2 vil 0 odelay 10 01 vth 0.6 0 1 vol 0 01 voh 1.2 01 vname node node ; initial pattern 1 0 1 1 0 1 1 1 0 1 0 0 1 X
DotVecMemory.in
* .VEC - SRAM 512K TEST - only input signals *
.vec "DotVecMemory.vec"
.OPTIONS ACCT=2
r1 da0 0 1
r2 da1 0 2
r3 wr 0 3
r4 rd 0 4
r5 pch 0 5
r6 wl0 0 6
r7 wl1 0 6
r8 wl2 0 6
r9 wl3 0 6
****************************
.TRAN 0.5ns 50ns
.options nomod nowarn
.tran 1n 250n
.print v(da0) v(rd) v(wr) v(pch) v(wl0) v(wl1) v(wl2) v(wl3)
.end
DotVecMemory.vec
; .VEC - SRAM 512K TEST - only input signals * RADIX 111111111 vname da0 da1 wr rd pch wl[0:3] io iiiiiiiii tunit ns vih 3.3v vil 0.0v triz 110000000 tdelay 0.5 110101110 0.0 000000000 5.0 101011000 25.0 100000000 30.0 011010100 50.0 010000000 55.0 101010010 75.0 100000000 80.0 011010001 100.0 010000000 105.0 000000000 120.0 zz0111000 140.0 zz0000000 145.0 zz0110100 165.0 zz0000000 170.0 zz0110010 190.0 zz0000000 195.0 zz0110001 215.0 zz0000000
004_dot_vec
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Graphics
