They match well near the resonant frequency, both the linear changes and frequency, which means a small phase distortion
As [H.sub.C] shows no ripple along the pass-bands and no phase distortion
, these characteristics allow the application of [H.sub.C] in a cascade implementation ((15) to improve the attenuation in the stopbands.
QMF bank has three type of distortion: amplitude distortion, phase distortion
and aliasing distortion.
To get rid of phase distortion
, decrease the harmonics pollution, and get faster dynamic response, a Predictive Current Control (PCC) strategy combined with PLL and band-stop filter is designed.
For second order Butterworth filtering, there is a phase lag of 90[degrees] between input and output of the filter at cutoff frequency causing phase distortion
. To cancel out this phase lag, the once-filtered data is filtered again in reverse direction of time.
Using MARP and DP may be a problem in a serial task because discontinuous movements may create phase distortion
in continuous relative phase curves.
2(b)) consisting of closely spaced eigenmodes with random phase distortion
. This phase distortion
is heavily dependent on the position of the ports and scatterers which determine the propagation condition.
(5) Phase distortion
:A waveform distortion attributable to changes in the signal's propagation delay that vary depending on the frequency.
These result in amplitude attenuation, wavelet phase distortion
and loss of resolution.
Linear devices such as filters typically add phase distortion
and group delay to the signal, and nonlinear components such as amplifiers cause intermodulation (IM) products that generate additional harmonics.
The criteria for amplitude and phase distortion
are the same.
In both cases the amplitude response of the whole (N-order) filter is identical but the phase response is not: the phase distortion
caused by the causal filter is the double of that of its N/2-order section, whereas that of the acausal filter is zero (the "direct" and "reverse" phase distortions