amplifier source load impedance measurement

[bsaulquin]

Dear all,

 

i would like to measure the complex source impedance output of an amplifier using the analog discovery 3 i have. I have the impedance module. i need to do impedance matching after the amplifier.

from what i read i need to put an input signal? like this the values are very far from what expected.

 

could you please help me thanks

 

[attila]

Hi @bsaulquin

See the Help tab of the application. Provide more information about the project and screenshot.

[bsaulquin]

Dear Attila, there is not much to say.

i bought a digilent discovery 3 with the impedance analyzer.

i am building a modem 

i bought an amplifier and want to measure output impedance using the digilent i  bought 

i am looking for help to get any information, i am sure it can be done 

many thks

[attila]

Hi @bsaulquin

See the following: 
https://www.google.com/search?q=how+to+measure+amplifier+output+impedance+%3F

For frequency response use the Network Analyzer and the spectrum options under Magnitude.

[bsaulquin]

Not sure to understand.

What is the procedure using the digilent discovery 3.

Do you mean the discovery 3 is à vna or do i have to use a vna instead ?

The spectrum option is for the discovery 3 or a vna?

May be it is trivial but not for me.

Many thanks

Regards

Edited March 26 by bsaulquin

[attila]

Hi @bsaulquin

 

The Impedance Analyzer is not suitable for such measurement.
This is intended for low power testing of component, passive filters...

The amplifier needs high power reference load.
https://sengpielaudio.com/calculator-InputOutputImpedance.htm

Here I used an floating external supply and 6.2R power resistor, I had at hand, connected to the output.

I measured an output impedance of 0.31 Ohms.

 

Here R1 is without and C2 is with load.
For me the THD and noise my be high due to the wiring or this is just a cheap amplifier.