Signal to noise calculation of a constant current source

Before you can calculate a signal to noise ratio you have to decide what your signal is, what your noise is, and what metric you want to use (I'll use 'power' without defining it). Then it's an easy thing to divide their respective powers and get a SNR.

The circuit shown has nothing that indicates what you're calling 'signal'. One could calculate the degree to which the circuit contributed to the noise power spectral density of the current in the load. Without knowing what your signal is and whether you want to filter your signal+noise somehow before calling it good you cannot calculate SNR.

So what are you _really_ doing, and does SNR really mean anything in that context?

Signal reference voltage, source impedance, bandwidth.

Bandwidth of interest, source impedance.

That differential amp isn't particularly quiet either.

Graham

Hi,

I need some document and tips which helps me to find the way to calculate it. like some body already did it and then I will replicate it with some modifications.

Regards John

Google ?

Why not post the requested data here and someone will probably post back the calaculation for you to see.

If you don't even know what bandwidth you need to calculate for though, you're frankly rather stuck !

Graham