Editing Bode plot (section)

===Magnitude plot===
The magnitude (in [[decibel]]s) of the transfer function above (normalized and converted to angular-frequency form), given by the decibel gain expression <math>A_\text{vdB}</math>:
:<math>\begin{align}
A_\text{vdB} &= 20 \log|H_{\text{lp}}(\mathrm{j}\omega)| \\
    &= 20 \log \frac{1}{\left| 1 + \mathrm{j} \frac{\omega}{\omega_\text{c}} \right|} \\
    &= -20 \log \left| 1 + \mathrm{j} \frac{\omega}{\omega_\text{c}} \right| \\
    &= -10 \log \left( 1 + \frac{\omega^2}{\omega_\text{c}^2} \right).
\end{align}</math>
Then plotted versus input frequency <math>\omega</math> on a logarithmic scale, can be approximated by ''two lines'', forming the asymptotic (approximate) magnitude Bode plot of the transfer function:
* The first line for angular frequencies below <math>\omega_\text{c}</math> is a horizontal line at 0&nbsp;dB, since at low frequencies the <math>\omega/\omega_\text{c}</math> term is small and can be neglected, making the decibel gain equation above equal to zero.
* The second line for angular frequencies above <math>\omega_\text{c}</math> is a line with a slope of −20&nbsp;dB per decade, since at high frequencies the <math>\omega/\omega_\text{c}</math> term dominates, and the decibel gain expression above simplifies to <math>-20 \log(\omega/\omega_\text{c})</math>, which is a straight line with a slope of −20&nbsp;dB per decade.

These two lines meet at the [[corner frequency]] <math>\omega_\text{c}</math>. From the plot, it can be seen that for frequencies well below the corner frequency, the circuit has an attenuation of 0&nbsp;dB, corresponding to a unity pass-band gain, i.e. the amplitude of the filter output equals the amplitude of the input. Frequencies above the corner frequency are attenuated{{snd}} the higher the frequency, the higher the [[attenuation]].