This e . g . allows the design of zero delay recursive filters, where the group delay of a causal filter is canceled by its Hermitian non-causal filter.
32.
An alternative form of group delay ripple, preferable to the equal amplitude Chebyshev ripple, has low amplitude ripples at low frequencies but ripples of increasing amplitude as frequency increases.
33.
The digital equivalent is the Thiran filter, also an all-pole low-pass filter with maximally-flat group delay, which can also be transformed into an allpass filter, to implement fractional delays.
34.
Note that the transition from the pass band to the stop band is much slower than for other filters, but the group delay is practically constant in the passband.
35.
The group delay characteristic for this expression can be derived as a power series expansion in ? about zero frequency ( i . e . a MacLaurin series ).
36.
Note that the group delay is by doubled, at this point, so that the results will apply to a sixth order all-pass network, rather than for the low-pass network.
37.
In fact, there is some phase information in the spectrogram, but it appears in another form, as time delay ( or group delay ) which is the Instantaneous Frequency.
38.
They also use acoustic suspension woofers ( sealed enclosures ), which have the lowest group delay of all configurations and thus the best chance of seamlessly integrating with the electrostatics.
39.
;Phase distortion ", " Group delay ", and " Phase delay : A perfect audio component will maintain the phase coherency of a signal over the full range of frequencies.
40.
A typical arrangement of poles and zeros to give, nominally, an electrical circuit with constant group delay follows the pattern shown in the figure below ( see also Stewart ).
