>From my Twister a 200MHz ringing 10mVpp leaks out, with the exact frequency of the clock signal. The gates inside are HC. The thing is in a shielded enclosure. There is a hole 5mm in the enclosure through which 1mm thick copper wire goes. In the place where it leaves there are 3 1uF and 1 100nF ceramic caps. Soldered with 2.5mm leads as close as possible. The place at the hole is connected with 2.5cm thin wire (from UTP) to the board. The board has 100nF and 10nF blocking. Farther into the board there is airwire coil 500nH to filter the power line. However it's not enough - there is still those 10mV noise going out and interfering with some people's TV.
I found some time ago that the mechanism how it gets out is that it catches on the 2.5cm wire like on an antenna and goes through the blocking caps on leaving the shielding enclosure because their impedance is too high to kill it. Do you think it will be solved when I put 47nH SMD 1210 size polymer core coil just before the leave-the-box caps? Or will it catch on the 47nH like on an antenna again? I would like to get it down at least to 1mVpp. I calculated the 47nH to have 100x attenuation with 300mOhm internal resistance of the capacitor. CL<
