@stdlib/simulate-iter-lanczos-pulse
v0.2.3TypeScript
Create an iterator which generates a Lanczos pulse waveform.
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iterLanczosPulse
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> Create an iterator which generates a Lanczos pulse waveform.
A Lanczos pulse waveform is represented by the following equation
where T is the pulse period, τ is the pulse duration, a is the amplitude, and φ is the phase offset.
Installation
``bash`
npm install @stdlib/simulate-iter-lanczos-pulse
Usage
`javascript`
var iterLanczosPulse = require( '@stdlib/simulate-iter-lanczos-pulse' );
#### iterLanczosPulse( \[options] )
Returns an iterator which generates a Lanczos pulse waveform.
`javascript
var it = iterLanczosPulse();
// returns
var v = it.next().value;
// returns
v = it.next().value;
// returns
v = it.next().value;
// returns
// ...
`
The returned iterator protocol-compliant object has the following properties:
- next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.
- return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.
The function supports the following options:
- period: pulse period (i.e., the number of iterations before a waveform repeats). Default: 100.2
- duration: pulse duration. Must be greater than . Default: options.period.1.0
- amplitude: amplitude. Default: .0
- offset: phase offset (in units of iterations; zero-based). A negative offset translates a waveform to the left. A positive offset translates a waveform to the right. Default: .1e308
- iter: number of iterations. Default: .
By default, the function returns an iterator which generates a waveform that repeats every 100 iterations. To specify an alternative period, set the period option.
`javascript
var opts = {
'period': 10
};
var it = iterLanczosPulse( opts );
// returns
var v = it.next().value;
// returns
v = it.next().value;
// returns
// ...
`
By default, the function returns an iterator which generates a waveform that has a duty cycle of 100% (i.e., the waveform duration equals the waveform period). To specify an alternative duty cycle, set the duration option. For example, to generate a waveform having a period of 10 iterations and a 50% duty cycle,
`javascript
var opts = {
'period': 10,
'duration': 5 // 5/10 = 0.50 => 50%
};
var it = iterLanczosPulse( opts );
// returns
var v = it.next().value;
// returns 0.0
v = it.next().value;
// returns
v = it.next().value;
// returns
v = it.next().value;
// returns
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
// ...
`
To adjust at what point the iterator begins in the waveform cycle, set the phase offset option. For example, to translate the waveform to the left,
`javascript
var opts = {
'period': 10,
'duration': 5,
'offset': -7
};
var it = iterLanczosPulse( opts );
// returns
var v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns
v = it.next().value;
// returns
// ...
`
To translate the waveform to the right,
`javascript
var opts = {
'period': 10,
'duration': 5,
'offset': 2
};
var it = iterLanczosPulse( opts );
// returns
var v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns 0.0
v = it.next().value;
// returns
v = it.next().value;
// returns
// ...
`
By default, the function returns an infinite iterator (i.e., an iterator which never ends). To limit the number of iterations, set the iter option.
`javascript
var opts = {
'iter': 2
};
var it = iterLanczosPulse( opts );
// returns
var v = it.next().value;
// returns
v = it.next().value;
// returns
var bool = it.next().done;
// returns true
`
Notes
- If an environment supports Symbol.iterator, the returned iterator is iterable.
Examples
`javascript
var iterLanczosPulse = require( '@stdlib/simulate-iter-lanczos-pulse' );
// Create an iterator:
var opts = {
'period': 50,
'duration': 25,
'amplitude': 10.0,
'offset': -25,
'iter': 100
};
var it = iterLanczosPulse( opts );
// Perform manual iteration...
var v;
while ( true ) {
v = it.next();
if ( v.done ) {
break;
}
console.log( v.value );
}
`
*
See Also
- [@stdlib/simulate-iter/pulse][@stdlib/simulate/iter/pulse]: create an iterator which generates a pulse waveform.
- [@stdlib/simulate-iter/periodic-sinc][@stdlib/simulate/iter/periodic-sinc]: create an iterator which generates a periodic sinc waveform.
*
Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
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---
License
See [LICENSE][stdlib-license].
Copyright
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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