I am plotting a Amplitude spectrum of a magnetic field?When I am using the Bode plot command I getting the exact curve.But when I using the normal method via 20*log(abs()), I am getting the trend but I am not getting the exact curve.Please help me?

I am trying to find out the amplitude of magnetic spectrum with the function for magnetic field is given by "H(w)=10*(s/0.006-1)*(s^2/0.64+((2*s)/0.8+1))*(s/10-1)*(s^2/2250000+((2*s)/1500+1))/((-s^2/0.000004+((2*s)/0.002+1))*(s^2/49+((2*s)/7+1))*(s^2/400000000+((2*s)/20000+1))*(s/100-1))".When I am using the code "s = tf('s'); sys =10*(s/0.006-1)*(s^2/0.64+((2*s)/0.8+1))*(s/10-1)*(s^2/2250000+((2*s)/1500+1))/((-s^2/0.000004+((2*s)/0.002+1))*(s^2/49+((2*s)/7+1))*(s^2/400000000+((2*s)/20000+1))*(s/100-1)) %w=[0.0001:10:10000]; %bode(...,w) bode(sys,{0.0001,10000})" I am getting the exact plot but when I calculating the absolute values and then using 20*log() to calculate I am getting the trend of the plot at some places and others I am facing problems.At the places where there is a mismatch the curves are strainght? Please help me.

Answer 1

[ROSHAN SINGH]

I am trying to find out the amplitude of magnetic spectrum with the function for magnetic field is given by "H(w)=10*(s/0.006-1)*(s^2/0.64+((2*s)/0.8+1))*(s/10-1)*(s^2/2250000+((2*s)/1500+1))/((-s^2/0.000004+((2*s)/0.002+1))*(s^2/49+((2*s)/7+1))*(s^2/400000000+((2*s)/20000+1))*(s/100-1))".When I am using the code "s = tf('s'); sys =10*(s/0.006-1)*(s^2/0.64+((2*s)/0.8+1))*(s/10-1)*(s^2/2250000+((2*s)/1500+1))/((-s^2/0.000004+((2*s)/0.002+1))*(s^2/49+((2*s)/7+1))*(s^2/400000000+((2*s)/20000+1))*(s/100-1)) %w=[0.0001:10:10000]; %bode(...,w) bode(sys,{0.0001,10000})" I am getting the exact plot but when I calculating the absolute values and then using 20*log() to calculate I am getting the trend of the plot at some places and others I am facing problems.At the places where there is a mismatch the curves are strainght? Please help me.