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Re: Audio Generator or Function Generator? Which to get?

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On 13/03/2017 09:32, Jasen Betts wrote:
> On 2017-03-13, oldschool@tubes.com <oldschool@tubes.com> wrote:
>> I've been looking into buying an Audio Generator (Sine and Square Wave).
>> I mainly want this to run thru an amplifier to listen to the frequency
>> repsonse of the amp and speakers. Nothing very scientific, just to see
>> what these amps and speakers can do.... And on occasion to inject an
>> audio signal into amp sections to dee if the audio is passing that
>> stage.
>
> Any reason you've not looked at PC software?

Indeed. I favour Daquarta (sp?) for this sort of thing.

The paid for version will even give you a realtime FFT vs time waterfall 
plot of the input signal and the signal generator part continues to work 
after the evaluation period. It can do the usual waveforms well enough 
for all but the most demanding tests.

It is easily good enough for most audio work and allows you to see 
harmonic content of signals in realtime. The only disadvantage is that 
it perhaps isn't going to like mains voltages on the inputs/outputs of 
your PC so you would need to be careful.

>> My search on ebay lead me to something called a "Function Generator".
>> What the heck is that??? And also called a DDS device. (I have no clue
>> what DDS means).
>
> look it up on wikipedia. it means that inside there's some sort of computer
> generating a digital wavform, that gets converted and comes out the output

There used to be old school analogue function generator chips that made 
a triangle wave and then applied diode shaping to get a pseudo-sine 
wave. HP made one design implementation that was surprisingly good.
Intersils 8038 was the poor mans alternative for DIY.

http://www.intersil.com/content/dam/intersil/documents/icl8/icl8038.pdf

These days DDS is probably the way to go since it can do so much more. 
Testing power amps it is wiser to use frequency shaped noise rather than 
pure sine waves since you can hit mechanical resonances and damage 
acoustic drivers with quite modest power levels of pure sine wave.

-- 
Regards,
Martin Brown

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Thread

Audio Generator or Function Generator? Which to get? oldschool@tubes.com - 2017-03-13 02:26 -0600
  Re: Audio Generator or Function Generator? Which to get? Colin Horsley <horsley-spam@westnet.com.au> - 2017-03-13 20:20 +1100
  Re: Audio Generator or Function Generator? Which to get? Jasen Betts <jasen@xnet.co.nz> - 2017-03-13 09:32 +0000
    Re: Audio Generator or Function Generator? Which to get? Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2017-03-14 09:22 +0000
      Re: Audio Generator or Function Generator? Which to get? Phil Allison <pallison49@gmail.com> - 2017-03-14 03:14 -0700
        Re: Audio Generator or Function Generator? Which to get? "pfjw@aol.com" <pfjw@aol.com> - 2017-03-14 05:13 -0700
  Re: Audio Generator or Function Generator? Which to get? Ralph Mowery <rmowery28146@earthlink.net> - 2017-03-13 10:13 -0400
  Re: Audio Generator or Function Generator? Which to get? "pfjw@aol.com" <pfjw@aol.com> - 2017-03-13 07:54 -0700
  Re: Audio Generator or Function Generator? Which to get? Jeff Liebermann <jeffl@cruzio.com> - 2017-03-13 09:27 -0700
    Re: Audio Generator or Function Generator? Which to get? oldschool@tubes.com - 2017-03-13 14:23 -0500
      Re: Audio Generator or Function Generator? Which to get? "pfjw@aol.com" <pfjw@aol.com> - 2017-03-13 12:33 -0700
        Re: Audio Generator or Function Generator? Which to get? oldschool@tubes.com - 2017-03-13 15:03 -0500
      Re: Audio Generator or Function Generator? Which to get? Ralph Mowery <rmowery28146@earthlink.net> - 2017-03-13 16:28 -0400
      Re: Audio Generator or Function Generator? Which to get? rickman <gnuarm@gmail.com> - 2017-03-14 19:57 -0400
  Re: Audio Generator or Function Generator? Which to get? amdx <nojunk@knology.net> - 2017-03-13 13:43 -0500
    Re: Audio Generator or Function Generator? Which to get? amdx <nojunk@knology.net> - 2017-03-13 14:01 -0500
    Re: Audio Generator or Function Generator? Which to get? oldschool@tubes.com - 2017-03-13 14:33 -0500
      Re: Audio Generator or Function Generator? Which to get? amdx <nojunk@knology.net> - 2017-03-13 14:51 -0500
      Re: Audio Generator or Function Generator? Which to get? rickman <gnuarm@gmail.com> - 2017-03-14 20:02 -0400
  Re: Audio Generator or Function Generator? Which to get? "Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com> - 2017-03-13 21:15 +0000
  Re: Audio Generator or Function Generator? Which to get? rickman <gnuarm@gmail.com> - 2017-03-14 14:31 -0400
  Re: Audio Generator or Function Generator? Which to get? jurb6006@gmail.com - 2017-03-15 00:22 -0700

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