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# stk::DelayL Class Reference

STK linear interpolating delay line class. More...

`#include <DelayL.h>`

Inheritance diagram for stk::DelayL:

List of all members.

## Public Member Functions
| DelayL (StkFloat delay=0.0, unsigned long maxDelay=4095)
| Default constructor creates a delay-line with maximum length of 4095 samples and zero delay.
| ~DelayL ()
| Class destructor.
void | setMaximumDelay (unsigned long delay)
| Set the maximum delay-line length.
void | setDelay (StkFloat delay)
| Set the delay-line length.
StkFloat | getDelay (void) const
| Return the current delay-line length.
StkFloat | contentsAt (unsigned long tapDelay)
| Return the value at tapDelay samples from the delay-line input.
StkFloat | lastOut (void) const
| Return the last computed output value.
StkFloat | nextOut (void)
| Return the value which will be output by the next call to tick().
StkFloat | tick (StkFloat input)
| Input one sample to the filter and return one output.
StkFrames & | tick (StkFrames &frames, unsigned int channel=0)
| Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
StkFrames & | tick (StkFrames &iFrames, StkFrames &oFrames, unsigned int iChannel=0, unsigned int oChannel=0)
| Take a channel of the `iFrames` object as inputs to the filter and write outputs to the `oFrames` object.

## Detailed Description

STK linear interpolating delay line class.

This class implements a fractional-length digital delay-line using first-order linear interpolation. If the delay and maximum length are not specified during instantiation, a fixed maximum length of 4095 and a delay of zero is set.

Linear interpolation is an efficient technique for achieving fractional delay lengths, though it does introduce high-frequency signal attenuation to varying degrees depending on the fractional delay setting. The use of higher order Lagrange interpolators can typically improve (minimize) this attenuation characteristic.

by Perry R. Cook and Gary P. Scavone, 1995 - 2010.

## Constructor & Destructor Documentation

stk::DelayL::DelayL | ( | StkFloat | delay = `0.0`,
|  | unsigned long | maxDelay = `4095` |
| ) |  |  |

Default constructor creates a delay-line with maximum length of 4095 samples and zero delay.

An StkError will be thrown if the delay parameter is less than zero, the maximum delay parameter is less than one, or the delay parameter is greater than the maxDelay value.

## Member Function Documentation

void stk::DelayL::setMaximumDelay | ( | unsigned long | delay | ) |

Set the maximum delay-line length.

This method should generally only be used during initial setup of the delay line. If it is used between calls to the tick() function, without a call to clear(), a signal discontinuity will likely occur. If the current maximum length is greater than the new length, no change will be made.

void stk::DelayL::setDelay | ( | StkFloat | delay | ) |

Set the delay-line length.

The valid range for delay is from 0 to the maximum delay-line length.

StkFloat stk::DelayL::contentsAt | ( | unsigned long | tapDelay | ) |

Return the value at tapDelay samples from the delay-line input.

The tap point is determined modulo the delay-line length and is relative to the last input value (i.e., a tapDelay of zero returns the last input value).

StkFloat stk::DelayL::nextOut | ( | void |  | ) | `[inline]`

Return the value which will be output by the next call to tick().

This method is valid only for delay settings greater than zero!

StkFrames & stk::DelayL::tick | ( | StkFrames & | frames,
|  | unsigned int | channel = `0` |
| ) |  |  | `[inline, virtual]`

Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.

The StkFrames argument reference is returned. The `channel` argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if _STK_DEBUG_ is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

Implements stk::Filter.

StkFrames & stk::DelayL::tick | ( | StkFrames & | iFrames,
|  | StkFrames & | oFrames,
|  | unsigned int | iChannel = `0`,
|  | unsigned int | oChannel = `0` |
| ) |  |  | `[inline]`

Take a channel of the `iFrames` object as inputs to the filter and write outputs to the `oFrames` object.

The `iFrames` object reference is returned. Each channel argument must be less than the number of channels in the corresponding StkFrames argument (the first channel is specified by 0). However, range checking is only performed if _STK_DEBUG_ is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

The documentation for this class was generated from the following file:

- DelayL.h

The Synthesis ToolKit in C++ (STK)
©1995-2010 Perry R. Cook and Gary P. Scavone. All Rights Reserved.