SignalProcessing.SqrtRaisedCosineSampleGenerator

java.lang.Object
- ptolemy.math.SignalProcessing.SqrtRaisedCosineSampleGenerator

All Implemented Interfaces:

DoubleUnaryOperation

Enclosing class:

SignalProcessing
```
public static class SignalProcessing.SqrtRaisedCosineSampleGenerator
extends java.lang.Object
implements DoubleUnaryOperation
```
This class generates samples of a square-root raised cosine pulse. The function computed is:
```
           4 x(cos((1+x)PI t/T) + T sin((1-x)PI t/T)/(4x t/T))
  h(t) =  ---------------------------------------------------
                PI sqrt(T)(1-(4 x t/T)²)
  
```
where x is the the excess bandwidth. This pulse convolved with itself will, in principle, be equal to a raised cosine pulse. However, because the pulse decays rather slowly for low excess bandwidth, this ideal is not closely approximated by short finite approximations of the pulse.
This implementation was 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. The implementation was then further optimized to cache computations that are independent of time.

- Constructor Summary
  
  Constructors
  Constructor Description
  
  SqrtRaisedCosineSampleGenerator(double firstZeroCrossing, double excess)
  Construct a SqrtRaisedCosineSampleGenerator.
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  double operate(double time)
  Operate on the operand, returning a value of the same type.
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SqrtRaisedCosineSampleGenerator
```
public SqrtRaisedCosineSampleGenerator(double firstZeroCrossing,
                                       double excess)
```
    Construct a SqrtRaisedCosineSampleGenerator.
    
    Parameters:
    
    firstZeroCrossing - The time of the first zero crossing of the corresponding raised cosine pulse.
    
    excess - The excess bandwidth of the corresponding raised cosine pulse (also called the rolloff factor).
- Method Detail
  - operate
```
public final double operate(double time)
```
    Description copied from interface: DoubleUnaryOperation
    
    Operate on the operand, returning a value of the same type.
    
    Specified by:
    
    operate in interface DoubleUnaryOperation
    
    Parameters:
    
    time - The operand.
    
    Returns:
    
    The results of the operation.