LOOK 08/08

LOOK 08/08 is a free PC program designed for signal analysis and graphical display. It also performs some digital signal processing functions and can save the results to a disk file. Input is from data files stored on disk or signals generated within the program.

Free for personal or educational use. Capability includes Fourier transforms, windows, filters, resampling, differentiation, integration, autocorrelation, convolution, crosscorrelation, and statistics.

Major Features:

1. LOOK can read time or frequency domain input signals from disk:
   • Real time domain data
   • Complex time domain data
   • Real frequency domain data
   • Complex frequency domain data
2. LOOK can read two independent real or complex signals of any type.
3. LOOK can generate real or complex signals from an arbitrary equation.
4. LOOK is intended for use with uniformly sampled data. That is, the sampling interval of the x axis (time, frequency or whatever) must be uniform throughout the data file. Non-uniformly sampled data is NOT supported except for the X-Y plot case.
5. The program can perform various signal processing operations:
   • Fourier transforms and inverse Fourier transforms
   • Windowing -- Cosine, Cosine-squared, Rectangular, Kaiser or notch.
   • Linear transforms -- add a constant, multiply by a constant, multiply by a complex exponential or multiply by a sinusoid
   • Filtering -- Chebyshev, Butterworth, Transitional, Bessel filter or arbitrary H(s) (Laplace transform). It will generate the filter functions and apply them to the input signal.
   • Change sampling rate -- upsample and downsample
   • Differentiation and integration
   • Autocorrelation
   • Convolution
   • Crosscorrelation
6. It can also graph, list or save to file various parameters of the input signal(s):
   • Real component
   • Imaginary component
   • Amplitude (absolute value)
   • Power
   • Phase
   • Instantaneous frequency (FM demodulation)
   • Group delay of filters
   • Deviation from linear phase
   • X-Y (Lissajous) graphs
   • Product of real and imaginary parts
   • Sum and difference of real and imaginary parts
   • Linear regression lines
7. It also computes:
   • Sliding window averages
   • Probability distributions
   • Cumulative distributions
   • Various statistics such as rms, mean, min, max, etc.

Enhancements:

• Include the ability to read wav files which have extra information included in the header (name of song and copyright notice).

Requirements:

• Windows 95 and higher