Is it possible to simulate ac signal with dc?..tia sal

Wed Sep 14, 2005 1:25 pm   

Greetings All

Before everyone says use an converter/inverter please read on to see if
what I'm trying to do is possible.

I have a program called cool edit pro which allows me to create different
frequency signals on the left and right audio channels using my sound card.
I was wondering if I offset/change the phase of the signals in a certain
way could I simulate an AC signal. I know the circuit programs Spice and
Multisim can due this within the compnter, but I would like to create an AC
TYPE signal using my sound card if possible...trying to keep it cheap.

Thanks Sal

Wed Sep 14, 2005 1:40 pm   

sal wrote:

Every audio signal you create with the sound card is an AC signal.
Could you be a little more specific?
--
St. John

Wed Sep 14, 2005 1:44 pm   

On 9/14/05 7:25 AM, in article Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130,
"sal" <sal_at_spp.net> wrote:


The signal Cool Edit generates IS an AC signal.

Wed Sep 14, 2005 2:07 pm   

Sal,

If you are outputting any tones, other than just a click, from your sound
card, you already have AC signals. When you say "different frequency
signals", those are AC (other than a frequency of zero Hertz, which is DC).

You also wrote, "I know the circuit programs Spice and Multisim can due this
within the compnter...". With Spice or Multisim, you typically set the
parameters of the AC input signal you desire, then "stimulate" the circuit
with that signal. Basically, these programs use math functions to simulate
the reaction of the stimulated circuit. Alternatively, as in the case of an
oscillator circuit, the program computes and displays the output based on
the circuit components chosen. I don't believe these programs simulate AC
signals from DC, unless you are talking the fact that digital computer
circuitry eventually boils down to 1's and 0's.

Did I misunderstand your question?

Richard

"sal" <sal_at_spp.net> wrote in message
news:Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130...

Wed Sep 14, 2005 2:32 pm   

"sal" <sal_at_spp.net> wrote in message
news:Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130...

Sal:

Cool Edit Pro, Great program.

Define what you mean by, "AC type signal". The sound you hear comming
from your speakers is AC. Your sound card cannot or should not output DC
voltages as speakers don't much care for DC current in the voice coil. Tell
more about what you are trying to do..

Wed Sep 14, 2005 3:56 pm   

"sal" <sal_at_spp.net> wrote in message
news:Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130...

Sal:

Cool Edit Pro, Great program.

Define what you mean by, "AC type signal". The sound you hear comming
from your speakers is AC. Your sound card cannot or should not output DC
voltages as speakers don't much care for DC current in the voice coil. Tell
more about what you are trying to do..

Wed Sep 14, 2005 9:00 pm   

On Wed, 14 Sep 2005 14:25:15 GMT, sal <sal_at_spp.net> wrote:


Your sound card produces AC signals - that's what sound is, that's
what the speakers need.

Am I missing something here? Are you meaning to say that you want to
put a DC offset on the AC signal the sound card normally outputs? Or
are you meaning to say you want to create a beat signal? Or mixer
output (sum and difference signal)?

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Thu Sep 15, 2005 12:49 am   

Not sure what you mean by "AC signal". Audio frequencies are AC.


"sal" <sal_at_spp.net> wrote in message
news:Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130...

Thu Sep 15, 2005 2:30 am   

Thanks all....

I was just trying to find a cheap way of using my sound card as a
frequency generator.

This is what I want to test out.
http://www.pat2pdf.org/pat2pdf/foo.pl


sal <sal_at_spp.net> wrote in news:Xns96D16B82A2E9Dsalsppnet_at_140.99.99.130:

Thu Sep 15, 2005 6:59 am   

sal wrote:

The output of your sound card IS AC. Be more specific in your request.
mike

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Thu Sep 15, 2005 7:30 am   

"sal" <sal_at_spp.net> wrote in message
news:Xns96D1F09FBF17Asalsppnet_at_140.99.99.130...

Returns Patent not found message.

Thu Sep 15, 2005 11:04 am   

sal wrote:

When I click on that link, the site gives me this error message:

"Patent not found. Please check the value you entered.
Number not defined."

Do you just want to generate a single-frequency sine wave? Cool Edit
2000 does that, so probably Cool Edit Pro does as well.

Open the program, then:
Click on "Generate"
Select "Tones"
In the "generate tones" window that appears:
Click on "A 440 (default)" in the "presets" section (to force all
settings to generate a single frequency)
Type in any audible frequency number next to "Base frequency"
Click "OK", then play it.

Mark

Thu Sep 15, 2005 11:09 am   

On Wed, 14 Sep 2005 14:25:15 GMT, sal <sal_at_spp.net> wrote:


First off, I'm guessing that by "AC" you mean "the waveform
that comes out of the wall outlets", namely 60 Hz or 50 Hz.
I suspect Cool Edit can do this easily. If not, my own DaqGen
freeware can certainly do it, and further allow you to add all
sorts of modulations, noise, and other imperfections if you
want to simulate real-world problems.

The strict use of the term AC simply means Alternating
Current, and doesn't imply a certain frequency. Sound
cards *only* put out AC, and can pretty much put out
anything up to half the selected sample rate on the high
frequency end. But on the low frequency end, they are
limited to a few Hz minimum (the minimum may be as high
as 20 Hz or more on some older cards). That's because
there are DC blocking capacitors in the output (and input)
lines. Since they are designed for audible sound, and
since you can't hear much below 20 Hz anyway (and since
this makes it *way* simpler/cheaper to design) this is no
big deal for most uses.

Let me know if you have any questions about your specific
simulation using DaqGen... there are a *lot* of controls,
which might be intimidating at first. But a simple 60 Hz
sine should be a piece of cake.

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

Thu Sep 15, 2005 11:20 am   

The signal comming out of the analog output jack(s) of your soundcard IS
AC. So you dont have to worry about converting it.

--Andy P




sal wrote:

Thu Sep 15, 2005 1:28 pm   

Sorry about that this link should work


I wanted to test this patent out using my sound card
http://www.pat2pdf.org/patents/pat4394230.pdf

"St. John Smythe" <UndisclosedRecipient_at_privacy.net> wrote in
news:dg9cb1$v8j$11_at_n4vu2.n4vu.com: