A band-stop filter passes frequencies above and below a certain range.A band-pass filter passes a limited range of frequencies.A high-pass filter passes high frequencies fairly well it is helpful as a filter to cut any unwanted low-frequency components.A low-pass filter is used to cut unwanted high-frequency signals.Typical examples of frequency function are: The larger weight, the more important is a close approximation. In relation to the desired frequency function, there may also be an accompanying weighting function, which describes, for each frequency, how important it is that the resulting frequency function approximates the desired one. To achieve steeper slopes, higher-order filters are required. For many purposes, this is not sufficient. This means that the slope of the frequency response is limited to 6 dB per octave. In particular, the steepness and complexity of the response curve is a deciding factor for the filter order and feasibility.ДЄ first-order recursive filter will only have a single frequency-dependent component. The filter should be implemented in particular hardware or softwareДЄn important parameter is the required frequency response.The computational complexity of the filter should be low.The filter should be localized (pulse or step inputs should result in finite time outputs).The filter should have a specific impulse response.The filter should have a specific phase shift or group delay.The filter should have a specific frequency response.Typical requirements which are considered in the design process are: 3.1 Simultaneous optimization in both domains.2.3 Discontinuities versus asymptotic behaviour.Although filters are easily understood and calculated, the practical challenges of their design and implementation are significant and are the subject of advanced research. The design of digital filters is a deceptively complex topic. Certain parts of the design process can be automated, but normally an experienced electrical engineer is needed to get a good result.

The filter design process can be described as an optimization problem where each requirement contributes to an error function that should be minimized. The purpose is to find a realization of the filter that meets each of the requirements to a sufficient degree to make it useful.

( December 2012) ( Learn how and when to remove this template message)ДЇilter design is the process of designing a signal processing filter that satisfies a set of requirements, some of which may be conflicting. Please help to improve this article by introducing more precise citations.

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Matlab filter designer specify order