Digital FR Measurements

Rarkov · 14th November 2003, 10:54 PM

Hi,
I am finally doing my dissetation for Uni. The subject is the measurement of frequency response from a standalone unit. It is limited to audio circuits and after calculating the FR it sends the results as a standard text file via RS232 to hyperterminal in the format:

frequency value

Anyway - up until today, I've been looking at strictly analogue methods:

PIC->VCO->Device Under Test->RMS2DC->ADC->PIC->RS232

but someone mentioned that I could use an impulse and convert the output from the device using FFT to retrieve the FR. Apparently this is a DSP trick called Dirac or something. Anyway - I'm looking at using the dsPIC range of products.

Can anyone give me any information about a digital method of FR measurement (NOT COMPUTERS PLZ!!!)

Thanks,
Gaz

till · 14th November 2003, 10:59 PM

use some signal like this instead of sine? http://www.ph.ed.ac.uk/~jonathan/thesis/node82.html

14th November 2003, 10:54 PM	#1
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Digital FR Measurements Hi, I am finally doing my dissetation for Uni. The subject is the measurement of frequency response from a standalone unit. It is limited to audio circuits and after calculating the FR it sends the results as a standard text file via RS232 to hyperterminal in the format: frequency value Anyway - up until today, I've been looking at strictly analogue methods: PIC->VCO->Device Under Test->RMS2DC->ADC->PIC->RS232 but someone mentioned that I could use an impulse and convert the output from the device using FFT to retrieve the FR. Apparently this is a DSP trick called Dirac or something. Anyway - I'm looking at using the dsPIC range of products. Can anyone give me any information about a digital method of FR measurement (NOT COMPUTERS PLZ!!!) Thanks, Gaz

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14th November 2003, 10:59 PM	#2
till Banned Join Date: Apr 2002 Location: Germany, Clausthal	use some signal like this instead of sine? http://www.ph.ed.ac.uk/~jonathan/thesis/node82.html