Therefore, since the signal from V3 is not present at the outputs of A1 and A2, the attenuation from V3 at 1 MHz to the mixer outputs is infinite. The 1 MHz inputs that each mixer receives are totally suppressed at the mixer outputs. The reason is that the balanced mixers A1 and A2 each deliver two outputs, one at the sum frequency of 1 MHz plus 1 MHz which equals 2 MHz and the other at the difference frequency of 1 MHz minus 1 MHz which equals zero Hz (hence the name zero frequency IF). However, the Bode plotter does not respond to this. Please consider this zero-frequency IF circuit from my Living Analog blog entitled, Zero frequency IF.įor the input V3, at the same frequency as the local oscillator represented by V1 and V2 at 1 MHz, the signal output at the junction of R3 and R4 replicates the signal input. To change the units on phase the function call would be: BodePaper(0.This is great, but there is a SPICE booby trap waiting for the unwary user of the Bode plotter. To make paper that goes from 0.1 Hz to 100 Hz, with the magnitude scale goingįrom -60 to 40 dB and the phase from -180 to 90 degrees, the function call would Om_hi the high end of the frequency scale. Om_lo the low end of the frequency scale. Units on the phase plot can be radians or degrees, at the discretion of theīodePaper(om_lo, om_hi, dB_lo, dB_hi, ph_lo, ph_hi, UseRad) Two semilog graphs for making Bode plots. > help BodePaperīodePaper is Matlab code to generate graph paper for Bode plots. The syntax for calling is given by the function's help file. There is also a fine in the repository called BodeMagPaper.m that creates only a magnitude plot. It and save it so that MatLab can find it (from the Matlab menu you can go toįile→Set Path and include the directory where you stored the BodePaper.m file.). The program described here, BodePaper.m, can be used to make paper. The magnitude plot and one for the phase. When making Bode plots one needs two pieces of semi-logarithmic paper, one for The code for BodePaper.m is available at

Multisim printing bode plots