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testing for filter response?
- Thread starter Moleculo
- Start date
Assuming you have a calibrated generator, and an o'scope which has a perfectly flat response within its specififed bandwidth (or a chart/formula to show/calculate the amount of response change with frequency), all you need to do is inject equal-amplitude signals at regular frequency intervals and meaure the input vs output of the filter, and record your data. You will then be able to build a graph of the filter response. Better yet, use one of those circuit simulator packages such as Circuitmaker or Electronics Workbench. Electronics Workbench even has a filter design wizard which really speeds up design.
yes, just plot P-P voltage vs frequency.
you could also use a detector to get a DC voltage on the scope, then if your scope is a storage scope, and your sweep generator has a volts/freq sweep output (or sweep ramp output), you could use X-Y mode and get the plot right on the scope, then if your scope is PC interfaceable, like with GPIB/parallel, or has print screen, there you go....
For example, most of my sources output a sweep voltage that corresponds to the start frequency of 0V and stop frequency of 10V. It is a ramp voltage that tracks my sweep.
Or, if you have a fancy analyzer with a sweep generator, you could just drive the filter with the generator output...
Or just whip out your vector network analyzer
you could also use a detector to get a DC voltage on the scope, then if your scope is a storage scope, and your sweep generator has a volts/freq sweep output (or sweep ramp output), you could use X-Y mode and get the plot right on the scope, then if your scope is PC interfaceable, like with GPIB/parallel, or has print screen, there you go....
For example, most of my sources output a sweep voltage that corresponds to the start frequency of 0V and stop frequency of 10V. It is a ramp voltage that tracks my sweep.
Or, if you have a fancy analyzer with a sweep generator, you could just drive the filter with the generator output...
Or just whip out your vector network analyzer
Oh yea, you probably don't have an extra $50K laying around for one of those...In that case, you can, all by yourself, build an N2PK vector network analyzer to measure filter response...amongst a but load of other neato stuff...
Build you one today, build you an N2PK
www.n2pk.com
:naughty :twsted :wow :wav :guitar :welcomeint :beer :moon :naughty
You gonna like it!
Build you one today, build you an N2PK
www.n2pk.com
:naughty :twsted :wow :wav :guitar :welcome
int :beer :moon :naughty You gonna like it!
Actually what's kinda funny is that I found that I have a book ("The Complete RF Technician's Handbook") that I just found tells you how to do exactly what I was asking about. I don't have time to post what it says right now, but I'll try to do it tomorrow.