FIR Low-pass Filter Component
The FIR Low-pass Filter amplifies frequencies below a set frequency, and attenuates the frequencies above that frequency. The FIR filter offers a steeper cutoff slope than IIR filters, and can be configured to have a linear phase response.
Inputs and Outputs
Note: The number of signal pins is variable and set in the component's Type Property.
Input Pins
Channels
Audio signal pins are represented by a (
) circle, and traditional wiring is represented by a thin black line. You can use Signal Names on audio signal pins.
By default, the FIR Low-Pass Filter component is set to a Mono channel, which provides one input and one output. Additionally, you can set the Properties to allow for Stereo, which gives you two inputs and outputs; or you can choose Multi-Channel, which will allow you to choose between 2 and 256 inputs and outputs.
Output Pins
Channels
Audio signal pins are represented by a () circle, and traditional wiring is represented by a thin black line. You can use Signal Names on audio signal pins.
By default, the FIR Low-Pass Filter component is set to a Mono channel, which provides one input and one output. Additionally, you can set the Properties to allow for Stereo, which gives you two inputs and outputs; or you can choose Multi-Channel, which will allow you to choose between 2 and 256 inputs and outputs.
Properties
Tip: For additional properties not listed, refer to the Properties Panel help topic for more information.
FIR Low-Pass Filter Properties
Transition Bandwidth (Octave)
Sets the bandwidth of the transition between the stopped frequencies and the passed frequencies.
Stopband Attenuation
Sets the attenuation level for the frequencies that are not passed.
Phase Response
Linear Phase - The delay is the same for all frequencies.
Minimum Phase - There is a minimal delay that varies with frequency.
Channels
Type
Sets the type of Channel available for Inputs and Outputs.
Count
Only appears when choosing Multi-Channel as the Type. Sets the number of Channels for Multi-channel. You can choose between 2 and 256.
Response Panel
Enabled
Determines if the Response Panel is visible in the Control Panel
Size
Determines the size of the Response Panel.
Controls
Note: When controls are changed on a design in Run mode, the output is muted (approximately 1 second) while the new coefficient set is loaded.
Response Graph
The scales for the Response Graph vary depending on the measurement method you select.
The vertical line of the crosshair cursor provides a readout of its position on the X axis scale.
The vertical movement of the horizontal crosshair follows the magnitude or amplitude of the signal.
Phase
The phase difference between the output of the filter and its input.
Bypass
Bypasses the filter.
Invert
Inverts the audio signal through the filter.
Mute
Mutes the output of the filter.
Gain (dB)
Controls the gain of the audio signal for the frequencies passed through the filter.
Frequency (Hz)
Sets the low end of the frequencies passed through the filter. Frequencies above this setting are passed.
Group Delay (ms)
The time it takes for an audio signal to travel through the filter.
Control Pins
The available Control Pins depend on settings in Properties.
|
Pin Name |
Value |
String |
Position |
Pins Available |
|---|---|---|---|---|
|
Bypass |
0 1 |
active bypass |
0 1 |
Input / Output |
|
Invert |
0 1 |
normal invert |
0 1 |
Input / Output |
|
Mute |
0 1 |
unmute mute |
0 1 |
Input / Output |
|
Gain |
-100 to 20 |
-100 dB to 20 dB |
0.000 to 1.00 |
Input / Output |
|
Frequency |
10.0 to 20,000 |
10 Hz to 20 kHz |
0.000 to 1.00 |
Input / Output |
|
Group Delay |
0.250 to 240 |
.250 ms to 240 ms |
0.000 to 1.00 |
Output |
