[sdiy] How to convert mis-matched noise measurements?

[Glen]

I've been looking at two different op-amp data sheets. I tried to compare the
noise specs of the two different parts, but they are specified with different
units / measurement techniques. Is there any easy way to convert these specs to
the same format? 

For example, one op-amp specs input noise voltage like this:

   F=20Hz-20kHz 5.0 uV RMS (max)

The other op-amp does it this way:

   F = 30 Hz            10nV / SQR(Hz)
   F =   1 kHz           6nV / SQR(Hz)


(That's the reciprocal of the square root of the frequency. I'm really not sure
how to write a square-root symbol in email.)


***********************

As for Noise current, we have this:

   F=20Hz-20kHz 25 pA RMS (max)   

Compared to this:

   F = 30 Hz            2.7 pA / SQR(Hz)
   F =   1 kHz          0.7 pA / SQR(Hz)

***********************  

Does anyone know how to accurately compare these mis-matched specs?


thanks,
Glen