PSpice ABM prob

A

Active8

Guest
hi:

i'm feeding an ABM expr part [ EXP1=acos(V(%IN)) ] with a 1Vpp sine
wave. i get errors saying my input is invalid (i.e., >1). something's
wrong here. my input is 2 1Vpp sines multiplied which is 1Vpp (probe
output doesn't even come close to the reported error values) and then
fed to the acos() part.

i see the acos function isn't even listed as an ABM math function in the
PSpice ref, but PSpice hasn't choked on it.

i also can't figure how to get the Average value of a sine wave. not
doable with an ABM expression, is it?

TIA,
mike
 
Active8 wrote:
hi:

i'm feeding an ABM expr part [ EXP1=acos(V(%IN)) ] with a 1Vpp sine
wave. i get errors saying my input is invalid (i.e., >1). something's
wrong here. my input is 2 1Vpp sines multiplied which is 1Vpp (probe
output doesn't even come close to the reported error values) and then
fed to the acos() part.

i see the acos function isn't even listed as an ABM math function in
the PSpice ref, but PSpice hasn't choked on it.

i also can't figure how to get the Average value of a sine wave. not
doable with an ABM expression, is it?
Click to expand...
Make a little integrator. I think pspice allows "time" as a variable, so
you can divide the integrated value by time.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
 
In article <2fomlv880d9r3mcnf28sprh24dnks49lrd@4ax.com>, Jim-T@golana-
will-get-you.com says...
On Sun, 07 Sep 2003 03:06:29 GMT, Active8
mcolasono@earthlink.net.invalid> wrote:

hi:

i'm feeding an ABM expr part [ EXP1=acos(V(%IN)) ] with a 1Vpp sine
wave. i get errors saying my input is invalid (i.e., >1). something's
wrong here. my input is 2 1Vpp sines multiplied which is 1Vpp (probe
output doesn't even come close to the reported error values) and then
fed to the acos() part.

i see the acos function isn't even listed as an ABM math function in the
PSpice ref, but PSpice hasn't choked on it.

From "pspcref.pdf":

ACOS(x) -1 <= x <= +1

So you must be going slightly over. Tweak your amplitudes slightly
lower.
Click to expand...
i have to "tweak" by .6 ... .7*Vmultout when over once. that's not
right. 1*1=1 from the mult.

mike
i also can't figure how to get the Average value of a sine wave. not
doable with an ABM expression, is it?

TIA,
mike

Running AVG(x) or interval AVG(x,t) in PROBE ONLY... NOT in an ABM.

...Jim Thompson
Click to expand...
 
On Sun, 07 Sep 2003 20:10:58 GMT, Active8
<mcolasono@earthlink.net.invalid> wrote:

[snip]
ACOS(x) -1 <= x <= +1

So you must be going slightly over. Tweak your amplitudes slightly
lower.

i have to "tweak" by .6 ... .7*Vmultout when over once. that's not
right. 1*1=1 from the mult.

mike
[snip]
Click to expand...

Congratulations! You've found a bug in PSpice. Looks like *both*
ASIN and ACOS are defective.

CHARLIE???

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
In article <9o5nlvohsovim993evdfm4r7797q0sevcb@4ax.com>, Jim-T@golana-
will-get-you.com says...
On Sun, 07 Sep 2003 20:10:58 GMT, Active8
mcolasono@earthlink.net.invalid> wrote:

[snip]

ACOS(x) -1 <= x <= +1

So you must be going slightly over. Tweak your amplitudes slightly
lower.

i have to "tweak" by .6 ... .7*Vmultout went over once. that's not
right. 1*1=1 from the mult.

mike
[snip]

Congratulations! You've found a bug in PSpice. Looks like *both*
ASIN and ACOS are defective.
Click to expand...
why do you say that? are those functions messing with you?

no. it's telling me the output of the multiplier is 1.2xxx, rather the
input to the acos function is to high. but as i said, the output of the
mult, when probed, never shows anything over 1. maybe a little over, but
not 1.2xxx or even the 1.4xxx i remember seeing on one run.

i can't figure out how the ABM integral works thank's to lame docs. the
integrator part *and* the STD function both return 0V DC for an input
sin/cos which goes from 0V to 1V.

mike
CHARLIE???

...Jim Thompson
Click to expand...
 
On Sun, 07 Sep 2003 21:01:46 GMT, Active8
<mcolasono@earthlink.net.invalid> wrote:

In article <9o5nlvohsovim993evdfm4r7797q0sevcb@4ax.com>, Jim-T@golana-
will-get-you.com says...
On Sun, 07 Sep 2003 20:10:58 GMT, Active8
mcolasono@earthlink.net.invalid> wrote:

[snip]

ACOS(x) -1 <= x <= +1

So you must be going slightly over. Tweak your amplitudes slightly
lower.

i have to "tweak" by .6 ... .7*Vmultout went over once. that's not
right. 1*1=1 from the mult.

mike
[snip]

Congratulations! You've found a bug in PSpice. Looks like *both*
ASIN and ACOS are defective.

why do you say that? are those functions messing with you?

no. it's telling me the output of the multiplier is 1.2xxx, rather the
input to the acos function is to high. but as i said, the output of the
mult, when probed, never shows anything over 1. maybe a little over, but
not 1.2xxx or even the 1.4xxx i remember seeing on one run.

i can't figure out how the ABM integral works thank's to lame docs. the
integrator part *and* the STD function both return 0V DC for an input
sin/cos which goes from 0V to 1V.

mike

CHARLIE???

...Jim Thompson
Click to expand...
I ran ACOS with just a single-sine input... crashed PSpice v9.2.3 :)

Reduced amplitude until it ran... 0.6V peak... output was absurd, but
*was* centered on 1.57 which smells like 1.57 radians = 90°.

Further testing reveals a cumulative problem. Works right up to input
amplitude of 0.99. Amplitude of 1.0 locks up PSpice, trying a smaller
value then crashes PSpice.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
In article <FhA6b.22$aF4.7@newsfep3-gui.server.ntli.net>,
kevin@anasoft.co.uk says...
Active8 wrote:
hi:

i'm feeding an ABM expr part [ EXP1=acos(V(%IN)) ] with a 1Vpp sine
wave. i get errors saying my input is invalid (i.e., >1). something's
wrong here. my input is 2 1Vpp sines multiplied which is 1Vpp (probe
output doesn't even come close to the reported error values) and then
fed to the acos() part.

i see the acos function isn't even listed as an ABM math function in
the PSpice ref, but PSpice hasn't choked on it.

i also can't figure how to get the Average value of a sine wave. not
doable with an ABM expression, is it?


Make a little integrator. I think pspice allows "time" as a variable, so
you can divide the integrated value by time.
Click to expand...
thought about that.

i can't figure out how the ABM integral works thank's to lame docs. the
integrator part *and* the SDT function both return 0V DC for an input
sin/cos which goes from 0V to 1V.


thanks,
mike
Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
Click to expand...
 
In article <o68nlvk9keh5ul0els1b69938h45br7j1h@4ax.com>, Jim-T@golana-
will-get-you.com says...
On Sun, 07 Sep 2003 21:01:46 GMT, Active8
mcolasono@earthlink.net.invalid> wrote:

In article <9o5nlvohsovim993evdfm4r7797q0sevcb@4ax.com>, Jim-T@golana-
will-get-you.com says...
On Sun, 07 Sep 2003 20:10:58 GMT, Active8
mcolasono@earthlink.net.invalid> wrote:

[snip]

ACOS(x) -1 <= x <= +1

So you must be going slightly over. Tweak your amplitudes slightly
lower.

i have to "tweak" by .6 ... .7*Vmultout went over once. that's not
right. 1*1=1 from the mult.

mike
[snip]

Congratulations! You've found a bug in PSpice. Looks like *both*
ASIN and ACOS are defective.

why do you say that? are those functions messing with you?

no. it's telling me the output of the multiplier is 1.2xxx, rather the
input to the acos function is to high. but as i said, the output of the
mult, when probed, never shows anything over 1. maybe a little over, but
not 1.2xxx or even the 1.4xxx i remember seeing on one run.

i can't figure out how the ABM integral works thank's to lame docs. the
integrator part *and* the SDT function both return 0V DC for an input
sin/cos which goes from 0V to 1V.

mike

CHARLIE???

...Jim Thompson


I ran ACOS with just a single-sine input... crashed PSpice v9.2.3 :)

Reduced amplitude until it ran... 0.6V peak... output was absurd, but
*was* centered on 1.57 which smells like 1.57 radians = 90°.

Further testing reveals a cumulative problem. Works right up to input
amplitude of 0.99. Amplitude of 1.0 locks up PSpice, trying a smaller
value then crashes PSpice.

...Jim Thompson
Click to expand...
that's what i got for a DC input... .99V max. the error for 1VDC says
the acos input is 1.001

that .6V sin wave seems to work here. returns a value in radians for the
given input. acos(.595) = .933, acos(-.593) = 2.2, acos(0) = 1.5708...
why we can't input 1V is beyond me.

mike
>
 
On Sun, 07 Sep 2003 22:44:17 GMT, Active8
<mcolasono@earthlink.net.invalid> wrote:

[snip]
Congratulations! You've found a bug in PSpice. Looks like *both*
ASIN and ACOS are defective.

why do you say that? are those functions messing with you?
[snip]
that's what i got for a DC input... .99V max. the error for 1VDC says
the acos input is 1.001

that .6V sin wave seems to work here. returns a value in radians for the
given input. acos(.595) = .933, acos(-.593) = 2.2, acos(0) = 1.5708...
why we can't input 1V is beyond me.

mike
Click to expand...
I have reported the problem to PSpice support.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
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