2023年9月16日 · The phase of the loop gain must start at -180 deg for negative feedback (when the phase inversion within the loop is taken into account). Thats all. For finding the phase margin, you have to identify the phase ot 0 dB loop gain. Whe the phase is 25 deg less than -360 deg - the PM is 25 deg.

2005年1月9日 · Re: Phase margin It can be proved as a general case that given a phase margin of 60° the amplifier's step response will not have any peaking, thus very less possibility for it to become stable. Thus 60 degrees is normally chosen to be the phase margin. 45° degrees is taken as a tradeoff, to have faster risetime and less settling time.

2006年6月16日 · phase margin in cadence calculator Run AC analysis, View waveform of gain and phase then measure phase at 0dB gain this will give you the phase margin. 60º phase margin upto about 180º is considered stable.

2013年12月19日 · From Fig X we could observe that, the Gain Margin=15.9 db. With gain crossover frequency = 7.62x103 rad.sec-1, and Phase Margin=88.8 deg. With phase crossover frequqncy=582 rad.sec-1. Since phase crossover frequency is very less than gain crossover frequency, the controller reveals that, the system is highly stable.".

2012年3月8日 · I am measuring phase margin for this bandgap using iprobe from analogLib in Cadence by breaking the loop and inserting iprobe between the output of op amp and gate of two top transistors. However, the problem is that I have heard that this method doesn't work for circuit that has more than one loop.

2012年3月8日 · For phase margin determination we need the loop gain. This is the gain (as a function of frequency) of all loop components (loop open) - including the sign inversion at the inv. opamp input. Because DC stability requires negative feedback at DC the loop gain phase must start at 0 Hz with -180deg.

2005年3月9日 · I am designing a 400-800MHz PLL. I have calculated Bandwidth and Phase Margin of the PLL. But I donot know how to understand Bandwidth and Phase Margin of PLL. Is it as same as Bandwidth and Phase Margin of op amp? How can I simulate Bandwidth and Phase Margin of a PLL?

2011年5月22日 · *The phase margin applies to systems with feedback only. It is a measure for "safety" against oscillations in case of a closed loop - but it will be measured/simulated in OPEN loop conditions. * Thus, you have to open the loop for applying a test signal ac source.

2011年8月9日 · Both control actions can be described with a transfer function. And these transfer functions have a frequency response with a phase response and a respective group delay. At the stability limit (phase margin zero) the group delay is infinite (phase jump) and the delay becomes smaller for a rising phase margin. That is the background of my question.

2014年7月7日 · The phase margin stability criterion is valid for loop gain characteristics with single crossover, as the present one is. In case of multiple crossover, you have to check the more general Nyquist criterion. Phase margin is by definition measured at unity loop gain ("0 db …