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From: Bill Kennedy on 26 Jun 2010 21:43
I have been using the tone generator in CoolEdit Pro for designing
continuous FM audio test signals (typically 10 minutes duration) and
the mix-paste function to add AM, noise, etc.

However, this method has a number of limitations. For example, the
phase relationships of different channnels cannot be adjusted.
Enveloping is tedious if if needs to be applied to the repetitive AM
component of an entire signal. CoolEdit will also not direct
individula channels to specific outputs of 5.1 or 7.1 soundcards.

Can anyone suggest any alternatives, which are more "advanced" in
these regards than CoolEdit, for producing complex audio test signals
entirely in software?

Bill Kennedy
From: Randy Yates on 27 Jun 2010 08:33
billkennedy(a)intertemp.com (Bill Kennedy) writes:

> I have been using the tone generator in CoolEdit Pro for designing
> continuous FM audio test signals (typically 10 minutes duration) and
> the mix-paste function to add AM, noise, etc.
>
> However, this method has a number of limitations. For example, the
> phase relationships of different channnels cannot be adjusted.
> Enveloping is tedious if if needs to be applied to the repetitive AM
> component of an entire signal. CoolEdit will also not direct
> individula channels to specific outputs of 5.1 or 7.1 soundcards.
>
> Can anyone suggest any alternatives, which are more "advanced" in
> these regards than CoolEdit, for producing complex audio test signals
> entirely in software?

Sure, Matlab or GNU-Octave. They will both write .wav files directly and
have an extensive set of vector math functions that can be used for creating
discrete-time test signals.
--
Randy Yates % "And all that I can do
Digital Signal Labs % is say I'm sorry,
mailto://yates(a)ieee.org % that's the way it goes..."
http://www.digitalsignallabs.com % Getting To The Point', *Balance of Power*, ELO
From: Bill Kennedy on 27 Jun 2010 18:51
On Sun, 27 Jun 2010 08:33:07 -0400, Randy Yates <yates(a)ieee.org>
wrote:

>Sure, Matlab or GNU-Octave. They will both write .wav files directly and
>have an extensive set of vector math functions that can be used for creating
>discrete-time test signals.
>

Thank you for your reply.

So, for example, let's say I want to generate a 10 minute signal that
consists of a frequency modulated AF (with specified deviation),
amplitude modulated at ELF with the latter being an arbitrary
(irregular) waveform. Then I want four of them with progressive 90
degree phase shifts.

I have looked at MatLab previously (and SciLab) and noted the rather
steep learning curve.

Before proceeding along these lines, I would need to know to what
extent signals of the above complexity are practical to implement, and
second where to find instructional material targeting, as closely as
possible, this specific use.

To help clarify the situation in my mind, is there any chance you
could provide a sample of the type of notation required for the
complex signal described above?

Finally, is it conceivable someone has already devised a MatLab
routine whereby the appropriate values for these type of signals could
be entered in fields?

Bill Kennedy
From: Richard Dobson on 27 Jun 2010 20:10
On 27/06/2010 23:51, Bill Kennedy wrote:
> On Sun, 27 Jun 2010 08:33:07 -0400, Randy Yates<yates(a)ieee.org>
> wrote:
>
>> Sure, Matlab or GNU-Octave. They will both write .wav files directly and
>> have an extensive set of vector math functions that can be used for creating
>> discrete-time test signals.
>>
>
> Thank you for your reply.
>
> So, for example, let's say I want to generate a 10 minute signal that
> consists of a frequency modulated AF (with specified deviation),
> amplitude modulated at ELF with the latter being an arbitrary
> (irregular) waveform. Then I want four of them with progressive 90
> degree phase shifts.
>


So, a simple FM tone with slow irregular tremolo.
You can do all of that and more with Csound. Text-based (various GUI
front-ends available), real-time plus read/writing multi-channel
soundfiles - you set up Unit Generators doing all sorts of synthesis and
modulation including audio-rate FM; and depending on which UGs you use
you can in most cases choose an arbitrary starting phase for
oscillators. And it is free. www.csounds.com


Richard Dobson
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