Filter Design Toolbox Release Notes

Chapter 1
Filter Design Toolbox 2.2 Release Notes

New Features

This section introduces the new features and enhancements added to the Filter Design Toolbox 2.2 since Version 2.1 (Release 12.1).

If you are upgrading from a release earlier than Release 12.1, you should read New Features in the Filter Design Toolbox 2.1 Release Notes.

Multiple Precision Fixed-Point Filters Support

The Filter Design Toolbox 2.2 now supports word lengths greater than 64 bits. Earlier versions limited your fixed-point word length to 53 bits or fewer and 64 bits or fewer for floating-point word length.

Now you can use word lengths up to the memory capacity of your machine.

In addition, fraction lengths can now be greater than the associated word length, and can be less than zero.

All MATLAB Platforms Supported

With this release, the Filter Design Toolbox runs on all MATLAB platforms.

Four Filter Design Functions Added

This version of the toolbox adds four new filter design functions:

• firceqrip--design constrained equiripple FIR filters
• iirnotch--design second-order IIR notch digital filters
• iircomb--design IIR comb notching or peaking digital filters
• iirpeak--design second-order IIR peaking (also called resonator) digital filters

Enhanced Filter Design Functions

The following design functions have been upgraded to use the Leja algorithm to determine the minimum phase polynomial and from that the filter coefficients:

• firminphase--design higher-order minimum phase filters (n=100 or more), with better minimum phase characteristics. Also, added a new syntax option

• firminphase(b, nz)
  

• so you can specify the number of zeros that lie on the unit circle. Providing your estimate of the number of zeros can significantly improve the computation.

• gremez--design higher-order minimum phase filters (n=100 or more) with the 'minphase' input argument. No changes to the syntax.

Five New Filter-Related Functions

Filter Design Toolbox 2.2 adds the ability to read and write Xilinx CORE Generator files, and the ability to realize models of quantized filters in Simulink^TM if you own the DSP Blockset and Fixed-Point Blockset.

These three functions expand your filter options and capabilities:

• coeread--Read a XILINX CORE Generator^TM coefficient (.coe) file
• coewrite--Write a XILINX CORE Generator^TM coefficient (.coe) file

• FDATool has a new option for exporting quantized filters as .coe files when you own the Filter Design Toolbox. From the Targets menu option on the toolbar, you select Export to XILINX Coefficient (.COE) file to export your existing quantized filter coefficients to a .coe file. Your current filter must be a quantized direct-form FIR filter with one section; you cannot export nonquantized filters as .coe files, nor multiple-section filters.

• realizemdl--Create a Simulink model of your quantized filter using blocks from the Fixed-Point Blockset, or DSP Blockset if you do not own Fixed-Point Blockset.

Two other functions provide signal interpolation and decimation capability:

• cicdecimate--use a cascaded integrator-comb (CIC) decimation filter to decrease the sampling rate for a signal
• cicinterpolate--use a cascaded integrator-comb (CIC) interpolation filter to increase the sampling rate for a signal

Filter Design Toolbox Release Notes

New Frequency Transformation Functions Added