On 6/18/08, Sean Breheny wrote: > Hi all, > > I'm working on a DDS (Direct Digital Synthesizer) and although it > works great, I'm having trouble keeping leakage from the several > digital clocks in the circuit from getting into the output. I've done > some tests which seem to indicate that even a 1cm piece of wire inside > the (shielded) container will pick up enough leakage to be a problem > (this is going to be the LO for a receiver). Are you sure is not about the phase noise ? In other words, the > problem doesn't seem to be conducted leakage through the circuit but > rather simple coupling to the tiny bit of wire at the end of the > shielded output cable as it connects to the PCB). Use either a SMD ferrite (around 1K impedance above 100MHz) or better a ferite ring on which turn twice the wire which is carrying the signal. So, can anyone tell > me what the usual practice is when you have a shielded can with > several RF signals present inside and you want to get *one* of them > out without the others leaking in? 50 ohm in/output impedance, real SMA connectors, real RF cables > > Thanks, > > Sean > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist