Re: Using a sound card for measurement.On Mon, 12 May 2008 05:34:19 -0700, Richard Crowley wrote:
> "Edmund" wrote ...
>> I want to do some testing with a sound card for measurements. A few
>> things I need are :
>> 1 Some player which can play 192kHz sampled sounds.
>
> So go shopping for a sound card that fits your requirements. Don't be
> surprised if you don't find any popular-priced products that will have
> that range, however. You may be forced to look at industrial lab
> equipment if you want waveform generation up in those ranges.
The sound card in my laptop is able to do that.
>> 2 A way of ?making? such sound file from a PCM data text file.
>
> The math for creating sine waves is pretty simple. Most any programming
> language (even one-chip microcontrollers) have a "sine" function.
OK that's not a problem, but I need play that sine, so I
expect it has to be in a some standardized format that
a windows player understands. So I must make an 192kHz
sampled wav file?? if that is possible.
>
>> 3 An oscilloscope program which can record about 20 minutes
>> of 192kHz sampled data and save it as PCM text data.
>
> Are you sure you want that? You are talking about 230,400,000 sample
> values per channel. Do you have the software it takes to analyze (or
> even view) a text file that large?
I realize it is quite a lot data but thats not a real problem, I don't
need all that, I need some parts of it. These parts I can easily select.
An alternative would be a 'logging' program that automatically
starts and stops simultaneous with the played or generated sound.
Recording all seems simple.
>
> You also don't mention any bit-depths (8 bit?, 16 bit?, 24 bit?) What
> is the application?
That depends what my sound card supports, 16 bit will be good enough.
One thing I like to do is automatically measure the impedance from
a speaker unit.
>
>> My sound card can produce a remarkably good sine wave up til a least 45
>> kHz ( did not yet test higher yet ) with a sound generator but this
>> generator can not automatic produce all frequencies I want.
>
> The only difference between a sine wave at 1KHz and a sine wave at
> 100KHz is the period. The math is the same
I am talking about the analoge output, measured with an oscilloscope.
>
>> What kind sound file format can be used for reproducing 96kHz with a PC
>> / laptop ?
>
> No difference from the one that will do 9.6 KHz. The difference is in
> the hardware, not the software or the data.
Hmm CD's use a sample rate of 44.1 kHz so that will definitely not
produce 96 kHz.
>
>> Is there any (free?) tool out there to make such a sound file?
>
> How are you making the files you are using now?
I don't have anything for it now, so far I only used a sound generator.
>
> There are free and inexpensive software applications that will create
> various waveforms using your computer sound card. Google can find them
> for you in a few milliseconds.
>
> If you get hardware that supports 192KHz, it will almost certainly come
> with software that will run it, or at least demonstrate its
> capabilities.
Not with my laptop :-)
Edmund