8.1 Amplify frequency response

# amplitude frequency response
set samples 160
A(jw) = ({0,1}*jw/({0,1}*jw+p1))*(1/(1+{0,1}*jw/p2))
p1 = 10
p2 = 10000
set dummy jw
set grid
set key
set logscale xy
set title "Amplitude Frequency Response"
set xlabel "jw (radians)"
set xrange [1.1 : 90000.0]
set ylabel "magnitude of A(jw)"
set autoscale  y
plot abs(A(jw))

# phase frequency response
set nolog y
set logscale x
set title "Phase Frequency Response"
set ylabel "Phase of A(jw) (degrees)"
plot 180/pi*arg(A(jw))

此例为某一放大器的频率响应图，先绘增益部份再绘相位部份。其将座标轴改为 对数方式显示。因 A(jw) 为一复数方程式，故增益部份取其函数实数部份，而相位 部份取其函数的相角的变化。