SignalProcessing.RaisedCosineSampleGenerator

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ptolemy.math
Class SignalProcessing.RaisedCosineSampleGenerator

java.lang.Object
 extended byptolemy.math.SignalProcessing.RaisedCosineSampleGenerator

This class generates samples of a raised cosine pulse, or if the excess is zero, a modified sinc function.

The function that is computed is:

 sin(PI t/T) cos(excess PI t/T)
 h(t) = ----------- * -----------------
 PI t/T 1-(2 excess t/T)²

This is called a "raised cosine pulse" because in the frequency domain its shape is that of a raised cosine.

For some applications, you may wish to apply a window function to this impulse response, since it is rather abruptly terminated at the two \ ends.

This implementation is ported from the Ptolemy 0.x implementation by Joe Buck, Brian Evans, and Edward A. Lee. Reference: E. A. Lee and D. G. Messerschmitt, Digital Communication, Second Edition, Kluwer Academic Publishers, Boston, 1994.

Constructor Summary
`SignalProcessing.RaisedCosineSampleGenerator(double firstZeroCrossing, double excess)` Construct a RaisedCosineSampleGenerator.

Method Summary
`double`	`operate(double time)` Return a sample of the raised cosine pulse, sampled at the specified time.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

public SignalProcessing.RaisedCosineSampleGenerator(double firstZeroCrossing,
 double excess)

Construct a RaisedCosineSampleGenerator.
Parameters:: firstZeroCrossing - The time of the first zero crossing, after time zero. This would be the symbol interval in a communications application of this pulse.; excess - The excess bandwidth (in the range 0.0 to 1.0), also called the rolloff factor.

Method Detail

public final double operate(double time)

Return a sample of the raised cosine pulse, sampled at the specified time.