Bessel may refer to:
Bessel functions, first defined by the mathematician Daniel Bernoulli and then generalized by Friedrich Bessel, are canonical solutions y(x) of Bessel's differential equation
Linear filters process time-varying input signals to produce output signals, subject to the constraint of linearity. In most cases these linear filters are also time invariant in which case they can be analyzed exactly using LTI system theory revealing their transfer functions in the frequency domain and their impulse responses in the time domain. Real-time implementations of such linear signal processing filters in the time domain are inevitably causal, an additional constraint on their transfer functions. An analog electronic circuit consisting only of linear components will necessarily fall in this category, as will comparable mechanical systems or digital signal processing systems containing only linear elements. Since linear time-invariant filters can be completely characterized by their response to sinusoids of different frequencies, they are sometimes known as frequency filters.
Friedrich Wilhelm Bessel was a German astronomer, mathematician, physicist, and geodesist. He was the first astronomer who determined reliable values for the distance from the sun to another star by the method of parallax. Certain important mathematical functions were named Bessel functions after Bessel's death, though they had originally been discovered by Daniel Bernoulli before being generalised by Bessel.
Wiener may refer to:
Robertson may refer to:
In electronics and signal processing, a Bessel filter is a type of analog linear filter with a maximally flat group delay, which preserves the wave shape of filtered signals in the passband. Bessel filters are often used in audio crossover systems.
Nordenskiöld or Nordenskjöld or Nordenskjold or Nordenskiold may refer to:
In mathematics, Fourier–Bessel series is a particular kind of generalized Fourier series based on Bessel functions.
Prototype filters are electronic filter designs that are used as a template to produce a modified filter design for a particular application. They are an example of a nondimensionalised design from which the desired filter can be scaled or transformed. They are most often seen in regard to electronic filters and especially linear analogue passive filters. However, in principle, the method can be applied to any kind of linear filter or signal processing, including mechanical, acoustic and optical filters.
In signal processing, network synthesis filters are filters designed by the network synthesis method. The method has produced several important classes of filter including the Butterworth filter, the Chebyshev filter and the Elliptic filter. It was originally intended to be applied to the design of passive linear analogue filters but its results can also be applied to implementations in active filters and digital filters. The essence of the method is to obtain the component values of the filter from a given rational function representing the desired transfer function.
In signal processing, a filter is a device or process that removes some unwanted components or features from a signal. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspect of the signal. Most often, this means removing some frequencies or frequency bands. However, filters do not exclusively act in the frequency domain; especially in the field of image processing many other targets for filtering exist. Correlations can be removed for certain frequency components and not for others without having to act in the frequency domain. Filters are widely used in electronics and telecommunication, in radio, television, audio recording, radar, control systems, music synthesis, image processing, computer graphics, and structural dynamics.
Bessel Fjord is a fjord in northeastern Greenland. Administratively it belongs to the NE Greenland National Park area.
King Christian X Land is an area of northeastern Greenland.
King Frederick VIII Land is a major geographic division of northeastern Greenland. It extends above the Arctic Circle from 76°N to 81°N in a North-South direction along the coast of the Greenland Sea.
Adolf S. Jensen Land is a peninsula in the southern limit of King Frederick VIII Land, northeastern Greenland. Administratively it belongs to the NE Greenland National Park area.
Queen Margrethe II Land is a peninsula in the northern limit of King Christian X Land, northeastern Greenland. Administratively it belongs to the NE Greenland National Park area.
Bessel Fjord is a fjord in northwestern Greenland. Administratively it belongs to the Avannaata municipality.