AVR-Chat

Doug Locke wrote:
> I wonder if someone could help me with some advice please. I am trying
> to use an AVR microcontroller to monitor an analogue signal. The
> signal is both very low and of high impedance, so initially I wish to
> experiment a little by using a general purpose amplifier between the
> source and the AVR. I have found a HP 465A or a Brookdeal 9452 for not
> too much cash. Does anyone have any experience with either instrument,
> the HP has fixed gains of 20db or 40db while the Brookdeal is
> apparently variable 30-100db so either has suitable gain.
> Thanks for your time.
> Doug Locke.

An important thing to specify is the signal bandwidth, or what the source
of the signal is. If you're "monitoring" the signal with a digital input,
you just need a comparator and simple RC filter. For an ADC input, an opamp
amplifier and some RFI filtering will do.