Circuit For frequency response analyser

[Wayne at NTL]

Hi

Has anyone got a circuit for a frequency response analyser .

cheers

 

[Stefan Heinzmann]

Hi

Has anyone got a circuit for a frequency response analyser .

.---------------. .----------. .-----------.
| | | | | |
| | | | | |
| Sinewave | | | | True RMS |
| Generator |----| DUT |----| Voltmeter |
| | | | | |
| | | | | |
| | | | | |
'---------------' '----------' '-----------'

 

[John Woodgate]

I read in sci.electronics.design that Stefan Heinzmann
online.com>) about 'Circuit For frequency response analyser', on Tue, 27
Jan 2004:

.---------------. .----------. .-----------.
| | | | | |
| | | | | |
| Sinewave | | | | True RMS |
| Generator |----| DUT |----| Voltmeter |
| | | | | |
| | | | | |
| | | | | |
'---------------' '----------' '-----------'

You don't really need a true RMS voltmeter. You measure frequency
response BELOW maximum output of the DUT, so you are measuring only sine
waves. The results you get when the DUT is overloaded are of no use at
all.

 

[Robert Lacoste]

For 10MHz-1GHz band you can have a look at my "Vector'Soc" transmission
vectorial network analyzer article published in Demcember 2002 in the
Circuit Cellar magazine (#149).

Friendly yours,

Robert Lacoste - ALCIOM : The mixed signals experts
http://www.alciom.com

 

[Wayne]

What artical was it in. And is this true Stephan Heinzmann. If so could
you send it either to me or to the New Group?


regards

Wayne

 

[Stefan Heinzmann]

What artical was it in. And is this true Stephan Heinzmann. If so could
you send it either to me or to the New Group?


regards

Wayne

Hi Wayne,

Paul is entirely right, provided that the DUT has negligible distortion.
If not, True RMS is preferred. See for example Langford-Smith "Radio
Designer's Handbook" 4th Ed. 1953, Chapter 37.3D