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ScopeFIR™ is a comprehensive tool
for Finite Impulse Response (FIR) filter design. It can:
- Design multi-band Complex FIR filters of the following types:
- Parks-McClellan (Equiripple). ScopeFIR can design Filters,
Hilbert Transformers, or Differentiators. Its "Simple Filter
Specification Editor" allows you to easily design simple single-passband
filters, and its "Advanced Filter Specification Editor" gives you
access to the full capability of the Parks-McClellan algorithm by allowing you
to enter any number of pass/stop bands, with any edge frequencies. ScopeFIR
lets you enter frequencies in terms of the sample rate, and enter band response
specifications in your choice of linear or dB units. Its
"Optimize" feature searches for the minimum number of
taps which meets specifications.
- Windowed Sinc. ScopeFIR can design lowpass, highpass, bandpass, or
bandpass filters with user-specified band edge frequencies, and using any of
its built-in data windows, including Dolph-Chebyshev, Blackman-Harris,
Kaiser-Bessel (with choice of Alpha), Hamming, Hanning, and Gaussian.
- Raised Cosine. ScopeFIR automatically designs Raised Cosine and Root
Raised Cosine filters (commonly used in digital data
communications systems) with the specified rolloff factor and length.
- Maxflat. ScopeFIR can design lowpass FIR filters having a maximally flat passband.
- Cascaded Integrator-Comb. ScopeFIR can design CIC filters, which are widely used in hardware-based multirate applications.
- Import. ScopeFIR lets you import filters which have been designed
with another application. This allows you to analyze them using ScopeFIR's
powerful plots and analysis capabilities, and to modify them using ScopeFIR's powerful
filter modification capabilities.
- Boxcar. ScopeFIR lets you fill the N taps with a constant to
create a "boxcar" (or comb) filter.
- Analyze FIR filters by:
- Examining the actual band ripple and attenuation values in the Band
Editor.
- Plotting the Frequency Response. ScopeFIR can plot the Magnitude,
Phase, Unwrapped Phase, Group Delay, and Phase Delay of the Inphase,
Quadrature, or Complex filters. (Plots include a sophisticated multi-level
zooming capability, and are similar to ScopeDSP's
plots.)
- Plotting the Impulse Response. ScopeFIR can plot the magnitude or
phase of the Inphase, Quadrature, or Complex Filter Impulse Responses.
- Viewing the coefficients in the Coefficient Editor. ScopeFIR lets
you edit the Inphase and/or Quadrature coefficients in decimal, binary or hex
formats. Coefficients can be copied to/from the Windows clipboard. (Registered version only.)
- Modify FIR filters by:
- Editing. ScopeFIR's built-in Coefficient Editor lets you manually
edit the coefficients in decimal, binary or hex text formats. Then, you can
plot the altered frequency and impulse responses.
- Scaling. Changes the gain of the filter. The coefficients can be
automatically scaled to a given gain at a given frequency, or can be
automatically scaled to a given maximum coefficient magnitude.
- Quantizing. Coefficients can be quantized to N bits.
- Mixing. The mix function mixes the coefficients with a sine of a
given frequency, which creates a complex bandpass filter with a new center
frequency from a real filter that was designed previously.
- Convolving. Combines two filters into a single set of coefficients.
- Zero-Stuffing, Zero-Padding, and Truncating. Allows
you to fine-tune the number of coefficients in your filter.
- Selecting a Polyphase Subfilter. Helps you create filters which have
fractional-sample delays .
- Read and write Real or Complex FIR filter coefficients in any of Iowegian's
common data file formats.
Of course, ScopeFIR also includes many graphical user interface goodies to
make your life in DSP a little easier.
The ScopeFIR distribution file also now includes:
- fir_algs.c: a free and open collection of FIR filter algorithms to help you implement FIR filters in C.
- multirate_algs.c: a free and open collection of multirate FIR filter algorithms to help you implement FIR decimators, interpolators, and resamplers in C.
- A comprehensive set of example ScopeFIR project files to get you started on FIR designs of all types.
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