ARB and an Audio amplifier.

Set up the sweep frequency on an ARB and add the DC offset then use an audio
amp to make the signal the correct level (needs to be DC coupled)

Just an idea...

Steve

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Marcel Duchamp
Sent: 04 June 2007 23:58
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Alternator Whine Simulator

Carey Fisher wrote:
> I need to simulate alternator whine on a power supply so that I can
> design a whine filter. (No, I'm not gonna use it on the kids...)
> The specs are:  Power Supply is 12-14VDC and will supply about 1 A
> to the Unit Under Test (UUT).  I want to be able to superimpose a 800-2000
Hz
> sine wave (and/or triangle, square, whatever) on the supply line at .5Vp-p
to maybe
> 6Vp-p.  I have an audio sig gen but I tried capacitive coupling to the
> DC line and, of course, the input Z of the UUT is too low for good
> results.
> Anybody got any ideas on how to do this simply?
> Thanks,
> Carey
> 
> 
I would look at opening the supply up and feeding the AC into the 
reference point of the regulating circuit, assuming there is one. You 
will need to check it's AC response over the range of interest but if 
this works, it will be far easier than trying to push the output around.

If you absolutely have to push the output around, try isolating it with 
as big a resistor as your setup can tolerate.
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