In a message dated 10/02/02, DSaum@............ writes:

> You can reject 60Hz if you have control of your a/d sampling rate, 
> or if you can integrate after the a/d.

       I used to set up our 12 Bit Integrating A/Ds so that they Integreted 
for a whole number of mains cycles, to eliminate mains noise almost 
completely. They gave me 10 SPS without any problems. 

       Another alternative is to include a Twin Tee notch filter set to the 
mains frequency. They can give >55 dB rejection, which is often good enough. 
The Set Frequency is 2xPixRxC. You may also find that there is a tiny bit of 
120 Hz feedthrough from the rectified AC. Some rectifiers have a snap action 
turn off which can cause problems. Voltage spikes which are synchronised with 
the mains can also give trouble.

       Regards,

       Chris Chapman
In a message dated 10/02/02, DSaum@............ writes:



You ca
n reject 60Hz if you have control of your a/d sampling rate, 

or if you can integrate after the a/d.



       I used to set up our 12 Bit Integrating A/Ds so that they Integreted for a whole numbe
r of mains cycles, to eliminate mains noise almost completely. They gave me 10 SPS without any problems. 



       Another alternative is to include a Twin Tee notch filter set to the mains frequency. 
They can give >55 dB rejection, which is often good enough. The Set Frequency is 2xPixRxC. You may also find that there is a
 tiny bit of 120 Hz feedthrough from the rectified AC. Some rectifiers have a snap action turn off which can cause problems. Vo
ltage spikes which are synchronised with the mains can also give trouble.



       Regards,



       Chris Chapman