Filters a set of data with a digital FIR filter.

Syntax

OutSignal = FirFilter(Order,Fc,Window,InSignal)

OutSignal = FirFilter(Order,Fc,Band,Window,InSignal)

OutSignal = FirFilter(Order,Fc1,Fc2,Window,InSignal)

Arguments

Name

Description

Order

A positive integer specifying the order of the filter. For high pass and band stop filter, the order must be even.

Fc

The corner frequency in Hz of a low pass or high pass filter, or a vector of two corner frequencies for a band pass or band stop filter. For a digital filter, Fc is normalized by the Nyquist frequency and has values in the interval (0,1). For an analog filter, Fc has positive value(s).

Band (optional)

The filter band specifier. When Fc is a value, Band can be either ‘low’ (default) or ‘high.’ When Fc is a vector, Band is omitted for a band pass filter and ‘stop’ for a band stop filter.

Window

A vector of length Order + 1 for windowing the impulse response.  An empty vector, [ ], results in a rectangular window.

Fc1, Fc2

For the Templex™ style convention, Fc1 and Fc2 are the normalized corner frequencies in Hz of a digital filter. For a low pass filter, Fc1 = 0. For a high pass filter, Fc2 = 0 or 1. For a band pass filter, Fc1 < Fc2. For a band stop filter, Fc1 > Fc2.

InSignal

A vector of real data to be filtered.

Outputs

Name

Description

OutSignal

A vector of filtered data. Same size as the input data.

Example

A low-pass second order digital FIR filter with a cut-off frequency at 250 Hz, where the data sampling frequency is 1000 Hz. Use the default window.

Syntax

OutData = FirFilter(2,0,250/500,[],InData)

Results

OutData is a vector of filtered data.

See Also:

ButterFilter

Cheby1Filter

Cheby2Filter

EllipFilter