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getBandwidth

Get 3 dB bandwidth

Description

example

BW = getBandwidth(npFilter) returns the 3 dB bandwidth for the notch peak filter. If the Specification property is set to 'Quality factor and center frequency', the 3 dB bandwidth is determined from the quality factor value. If the Specification property is set to 'Coefficients', the 3 dB bandwidth is determined from the BandwidthCoefficient value and the sample rate.

Examples

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Create a dsp.NotchPeakFilter object with the Specification property set to 'Quality factor and center frequency'. The default quality factor Q is 5, and the center frequency Fc is 11,025 Hz.

np = dsp.NotchPeakFilter('Specification','Quality factor and center frequency')
np = 
  dsp.NotchPeakFilter with properties:

      Specification: 'Quality factor and center frequency'
      QualityFactor: 5
    CenterFrequency: 11025
         SampleRate: 44100

Compute the 3 dB bandwidth of the notch peak filter using the getBandwidth function. The bandwidth is computed as the ratio of the center frequency and the quality factor, FcQ.

getBandwidth(np)
ans = 2205

Visualize the filter response using fvtool.

fvtool(np)

Figure Filter Visualization Tool - Magnitude Response (dB) contains an axes object and other objects of type uitoolbar, uimenu. The axes object with title Magnitude Response (dB) contains an object of type line.

Input Arguments

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Notch peak filter whose 3 dB bandwidth is measured, specified as a dsp.NotchPeakFilter object.

Output Arguments

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3 dB bandwidth of the filter, returned as a scalar.

Data Types: double

Introduced in R2014a