Magnitudresponsen

Magnitudresponsen, often called the magnitude response, is a characteristic of linear time-invariant systems that describes how the amplitude of the output signal varies with the frequency of a sinusoidal input. It is obtained from the system’s frequency response, typically represented as a complex function H(jω) for continuous-time systems or H(e^{jΩ}) for discrete-time systems. The magnitude response is the nonnegative function |H(jω)| (or |H(e^{jΩ})|), and is commonly expressed in decibels as 20 log10|H(jω)|. The phase response, given by ∠H(jω), describes the frequency-dependent phase shift imposed by the system.

To compute the magnitude response, one can use the system’s transfer function H(s) or impulse response h(t) (continuous) or h[n] (discrete). For continuous time, H(jω) is the Fourier transform of h(t); for discrete time, H(e^{jΩ}) is the discrete-time Fourier transform of h[n]. The magnitude response indicates how different frequency components are attenuated or amplified, revealing whether the system behaves as a low-pass, high-pass, band-pass, or all-pass filter.

Applications of magnitudresponsen include filter design, audio processing, telecommunications, and control engineering. It is essential for assessing performance such as bandwidth, selectivity, and stability margins. In practice, magnitude response can be obtained analytically from a known transfer function or measured experimentally using signal excitation (impulse or swept sine) and Fourier analysis, often visualized with a Bode magnitude plot.