Leon Heller, G1HSM Suzuki SV1000S motorcycle [EMAIL PROTECTED] http://www.geocities.com/leon_heller ----- Original Message ----- From: "Frank" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, October 23, 2006 4:24 AM Subject: [soft_radio] Power supply filtering: When a C becomes RLC and an L becomes an RLC
> Power supply filtering: When a C becomes RLC and an L becomes an RLC > Hello, > I have a circuit with one digital and one analog 7805 regulator. I am > having trouble filtering out the EMI caused 64MHz 5V oscillator in the > digital circuit from entering the 7805 regulator on the analog > circuit. I built some filters using second order LC, pi C-R-C > circuits, pi C-L-C with limited success. I tested them all on a plain > pre-drilled board where I soldered the components in a neat fashion > and checked using 5V oscillator modules with a 100MHz oscilloscope and > 10X probes . All of them attenuated well 5V square waves up to a few > MHz, but when I put a 64MHz signal at the input, it just went straight > though. It is as if all the capacitors have parasitic inductances that > make the components act like inductors and the inductors acted like > L-C resonators... Could somebody recommend a topology for my filters , > type of dielectric, type of inductor etc... > Frank How about a 64 MHz notch filter? You really need a decent layout with careful attention paid to the analogue and digital ground connections. 73, Leon -- Leon Heller, G1HSM Suzuki SV1000S motorcycle [EMAIL PROTECTED] http://www.geocities.com/leon_heller Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/soft_radio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
