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Parametric EQ Filter

Second-order parametric equalizer filter

  • Library:
  • Audio System Toolbox / Filters

Description

The Parametric EQ Filter block filters each channel of the input signal over time using a specified center frequency, bandwidth, and peak (dip) gain. This block offers tunable filter design parameters, which enable you to tune the filter characteristics while the simulation is running. The filter uses a coupled allpass structure to optimize joint computation of the peak and notch response.

This block supports variable-size input, enabling you to change the channel length during simulation. To enable variable-size input, clear the Inherit sample rate from input parameter. The number of channels must remain constant.

Ports

Input

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  • Matrix input –– Each column of the input is treated as an independent channel.

  • 1-D vector input –– The input is treated as a signal channel.

Data Types: single | double

Output

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The Parametric EQ Filter block outputs a signal with the same data type as the input signal. The size of the output depends on the size of the input:

  • Matrix input –– The block outputs a matrix the same size and data type as the input signal.

  • 1-D vector input –– The block outputs an N-by-1 matrix (column vector), where N is the number of elements in the 1-D vector.

Data Types: single | double

Parameters

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If a parameter is listed as tunable, then you can change its value during simulation.

  • Bandwidth and center frequency –– Design the filter using Filter bandwidth (Hz), Equalizer center frequency (Hz), and Gain (dB).

  • Coefficients –– Design the filter using Bandwidth coefficient, Center frequency coefficient, and Gain (Linear Units).

  • Quality factor and center frequency –– Design the filter using Equalizer center frequency (Hz), Gain (dB), and Quality factor.

Tunable: No

Specify the filter bandwidth as a positive scalar that is less than half the sample rate of the input signal.

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Bandwidth and center frequency.

Specify the center frequency as a positive scalar that is less than half the sample rate of the input signal.

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Bandwidth and center frequency or Quality factor and center frequency.

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Bandwidth and center frequency or Quality factor and center frequency.

  • -1 corresponds to the maximum bandwidth (one-fourth the sample rate of the input signal).

  • 1 corresponds to the minimum bandwidth (0 Hz, that is, an allpass filter).

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Coefficients.

  • -1 corresponds to the minimum center frequency (0 Hz).

  • 1 corresponds to the maximum center frequency (half the sample rate of the input signal).

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Coefficients.

A value greater than one boosts the input signal. A value less than one attenuates the input signal.

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Coefficients.

Tunable: Yes

Dependencies

To enable this parameter, set Filter specification to Quality factor and center frequency.

When you select this parameter, the block inherits its sample rate from the input signal. When you clear this parameter, you specify the sample rate in Input sample rate (Hz).

Tunable: No

Tunable: Yes

Dependencies

To enable this parameter, clear the Inherit sample rate from input parameter.

  • Interpreted execution –– Simulate model using the MATLAB® interpreter. This option shortens startup time and has simulation speed comparable to Code generation. In this mode, you can debug the source code of the block.

  • Code generation –– Simulate model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time but the speed of the subsequent simulations is faster compared to Interpreted execution.

Tunable: No

References

[1] Orfanidis, Sophocles J. Introduction to Signal Processing. Upper Saddle River, NJ: Prentice-Hall, 1996.

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