I'm looking for an opamp adder in an eval board or "black box" that I can use to add (not mix) two RF signals of between about 80 and 150 MHz. I know I could build one using any number of available opamps but I'm looking for a proven design that I don't have to analyze/verify myself. Thanks. - Martin K --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .