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Re: [Help-gnucap] (no subject)
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From: |
al davis |
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Subject: |
Re: [Help-gnucap] (no subject) |
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Date: |
Tue, 9 Apr 2013 13:41:03 -0400 |
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User-agent: |
KMail/1.13.5 (Linux/2.6.32-5-amd64; KDE/4.4.5; x86_64; ; ) |
On Sunday 07 April 2013, Karl Hammar wrote:
> I get different volt calculated vs. measured in node 2 of
> simulation below. Can anyone point to where my mistake is?
>
> It should be 0.5 V for 50 Ohm input impedance but only
> measures to less than 200 mV. Replacing circuit 50 Ohm BNC
> terminator gives me the correct 500mV.
>
> My stuff is available in:
>
> http://turkos.aspodata.se/git/openhw/rfid/
It works for me.
My guess at where the mistake is .. something you haven't shown
us.
From your batch file ...
#Freq I(L) V(2)
12.5E+6 0.023063 0.030071
12.51E+6 0.023253 0.031361
.....
13.55E+6 0.073021 0.49164
13.56E+6 0.073039 0.49553
13.57E+6 0.072994 0.49898
13.58E+6 0.072886 0.50198
13.59E+6 0.072715 0.50454
13.6E+6 0.072482 0.50665
13.61E+6 0.07219 0.50831
13.62E+6 0.071839 0.50953
13.63E+6 0.071434 0.51032
13.64E+6 0.070975 0.51068
13.65E+6 0.070468 0.51063
13.66E+6 0.069913 0.5102
13.67E+6 0.069317 0.50939
13.68E+6 0.06868 0.50822
13.69E+6 0.068009 0.50673
13.7E+6 0.067305 0.50492
13.71E+6 0.066573 0.50283
13.72E+6 0.065816 0.50047
I also ran some interactive tests.
Gnucap 2009.12.07 RCS 26.136
.....
gnucap> spice
gnucap-spice>C1a 2 4 7.39e-10
gnucap-spice>C1b 0 3 7.39e-10
gnucap-spice>C2 2 0 1.65e-09
gnucap-spice>Cpar 4 3 1e-11
gnucap-spice>L 4 3 4.4e-07
gnucap-spice>Rpar 4 3 1500
gnucap-spice>.print ac z(2) zp(2) zr(2) zi(2)
gnucap-spice>.ac 12meg 14meg 10k
#Freq z(2) zp(2) zr(2) zi(2)
12.Meg 1.6451 -72.192 0.50313 -1.5663
12.01Meg 1.6104 -71.54 0.50991 -1.5275
.....
12.28Meg 0.81418 -21.71 0.75642 -0.30118
12.29Meg 0.80752 -17.859 0.76861 -0.24764
12.3Meg 0.80467 -13.907 0.78108 -0.1934
12.31Meg 0.80583 -9.8929 0.79384 -0.13845
12.32Meg 0.81114 -5.8555 0.80691 -0.082753
12.33Meg 0.82071 -1.8369 0.82028 -0.026307
12.34Meg 0.83455 2.1224 0.83398 0.030907
12.35Meg 0.85266 5.9852 0.84801 0.088909
.....
13.55Meg 48.258 5.1804 48.061 4.3574
13.56Meg 49.099 1.9652 49.07 1.6837
13.57Meg 49.789 -1.3062 49.776 -1.135
13.58Meg 50.316 -4.6125 50.153 -4.0463
13.59Meg 50.671 -7.9309 50.187 -6.9915
13.6Meg 50.85 -11.238 49.875 -9.9101
13.61Meg 50.855 -14.512 49.233 -12.743
13.62Meg 50.694 -17.73 48.286 -15.438
13.63Meg 50.376 -20.874 47.069 -17.95
13.64Meg 49.917 -23.928 45.627 -20.246
13.65Meg 49.335 -26.877 44.006 -22.303
13.66Meg 48.648 -29.712 42.252 -24.112
.....
gnucap-spice>r0 1 2 50
gnucap-spice>V1 1 0 generator(1) ac 1
gnucap-spice>.print ac v(2) vp(2) vr(2) vi(2)
gnucap-spice>.ac
#Freq v(2) vp(2) vr(2) vi(2)
12.Meg 0.032559 -70.415 0.010914 -0.030675
12.01Meg 0.031868 -69.808 0.011 -0.02991
.....
12.28Meg 0.016041 -21.37 0.014938 -0.0058451
12.29Meg 0.015906 -17.579 0.015163 -0.0048039
12.3Meg 0.015846 -13.689 0.015396 -0.0037499
12.31Meg 0.015865 -9.7367 0.015636 -0.002683
12.32Meg 0.015965 -5.7622 0.015884 -0.0016029
12.33Meg 0.016149 -1.8072 0.016141 -509.29u
12.34Meg 0.016417 2.0876 0.016406 598.03u
12.35Meg 0.016769 5.8851 0.01668 0.0017193
.....
13.55Meg 0.49164 2.6362 0.49112 0.022612
13.56Meg 0.49553 0.99154 0.49545 0.0085749
13.57Meg 0.49898 -0.6545 0.49894 -0.0056998
13.58Meg 0.50198 -2.299 0.50158 -0.020137
13.59Meg 0.50454 -3.939 0.50335 -0.034659
13.6Meg 0.50665 -5.5716 0.50426 -0.04919
13.61Meg 0.50831 -7.194 0.50431 -0.063655
13.62Meg 0.50953 -8.8035 0.50353 -0.077982
13.63Meg 0.51032 -10.398 0.50194 -0.092101
13.64Meg 0.51068 -11.974 0.49957 -0.10595
13.65Meg 0.51063 -13.53 0.49646 -0.11947
13.66Meg 0.5102 -15.064 0.49266 -0.1326
.....
It's interesting that zero-phase occurs at a different frequency
than max voltage or max impedance.
Your use of the "generator" keyword is probably not what you
want, but that is not the problem here. Since you specified an
AC value, it overrides the "generator" making it apply only to
transient analysis.