>Any comparator can only do a greater/less than operation. Thanks Gerhard - as I thought! >In fact, there exists nothing like equality of two signals, there exists only the >possibility that the absolute value of the difference between two signals >is less than some threshold. So could I do the sort of comparison you describe above using an ADC on a PIC? Thanks Alan -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu