Component: Filter (DSP)

Author	Matrix Ltd
Version	1.2
Category	DSP

Image Filter component

Filter component to allow basic filtering to be performed Filters include: LowPass, HighPass, BandPass, BandStop, FIR, IIR

Examples

Low Pass Filter

Example of the filter component set up to create a low pass filter with the input frequency controlled using the potentiometer on the panel.

File:LowPassFilter.fcfx

Low pass filter running at a low frequency - note that the amplitude of the filtered data closely matches that of the original waveform data.

Low pass filter running at a high frequency - note that the amplitude of the filtered waveform is now greatly attenuated.

High Pass Filter

Example of the filter component set up to create a high pass filter with the input frequency controlled using the potentiometer on the panel.

File:HighPassFilter.fcfx

High pass filter running at a low frequency - note that the amplitude of the filtered waveform is greatly attenuated.

High pass filter running at a high frequency - note that the amplitude of the filtered data closely matches that of the original waveform data.

Band Pass Filter

Example of the filter component set up to create a band pass filter with the input frequency controlled using the potentiometer on the panel.

File:BandPassFilter.fcfx

Band pass filter running at a low frequency - note that the amplitude of the filtered waveform is greatly attenuated.

Band pass filter running at a mid frequency - note that the amplitude of the filtered data closely matches that of the original waveform data.

Band pass filter running at a high frequency - note that the amplitude of the filtered waveform is greatly attenuated.

Downloadable macro reference

Filter

Performs the filter operation to the contents of the entire buffer in one go.

Parameters

This macro has no parameters

Return value

This call does not return a value

FilterTick

Performs the filter operation to the current value in the buffer.

Parameters

This macro has no parameters

Return value

This call does not return a value

Simulation macro reference

This component does not contain any simulation macros

Property reference

Buffer Manager

This property is of type Fixed list of ints and can be referenced with the variable name buffer_manager.

Determines which buffer manager component to refer to

Input

This property is of type Fixed list of ints and can be referenced with the variable name input_a.

Specifies the input buffer which will pass values into the filter

Output

This property is of type Fixed list of ints and can be referenced with the variable name output_c.

Specifies the output buffer which will store values from the filter

Type

This property is of type Fixed list of ints and can be referenced with the variable name type.

Specifies the filter type created by the component:

Low Pass - Filters out frequencies above the cutoff frequency

High Pass - Filters out frequencies below the cutoff frequency

Band Pass - Combination of High Pass and Low Pass Filters

Band Stop - Inverse of Band Pass

FIR - Finite impulse response using standard filter coefficients

IIR - Infinite impulse response using standard filter coefficients

Coefficient 0

This property is of type Signed integer and can be referenced with the variable name coef0.

Cutoff frequency = Nyquist frequency / Coefficient

Cutoff frequency is described as when the unwanted frequencies in the signal have been attenuated by at least 50%

Sample Rate

This property is of type Floating point and can be referenced with the variable name sample_rate.

Sample frequency used to work out some basic useful calculations

Nyquist Frequency

This property is of type Floating point and can be referenced with the variable name nyquist.

Maximum theoretical frequency that can be obtained by the sample frequency

Cutt Off Frequency 0

This property is of type Floating point and can be referenced with the variable name cut_off_0.

First cutoff frequency