Fig. 4. Nyquist chart created from the Bode plot data in Fig. 1 shows the phase margin, gain margin, and stability margin. Three points are indicated on the Nyquist chart; phase margin, gain ...

Bode plots – or frequency response graphs – are found in just about every piece of literature for high-end audio equipment. It’s a simple idea, graphing frequency over amplitude, … ...

The Bode plot shown above in Fig. 6 has a phase margin of 46 degrees at a crossover frequency of 3.92MHz. The minimum distance from (1,0) occurs at 5.50MHz with a phase of 34 degrees.

This is great, but there is a SPICE booby trap waiting for the unwary user of the Bode plotter. Please consider this zero-frequency IF circuit from my Living Analog blog entitled, Zero frequency IF.