Design a digital ring oscillator using logic inverters that have propagation delay times of tPLH = 28ns and tPHL = 42ns. 3. The attempt at a solution I'm using a general ring oscillator design using 3 CMOS inverters like this: http://upload.wikimedia.org/wikipedia/commons/7/75/Ring_osc_5.png I can't get this to work in Capture (Pspice) though. All I'm getting on the ouput is a DC signal. Can somebody explain to me how to get an oscillator to work in Capture? Also, how would you measure the tPLH and tPHL values?