# iterFlatTopPulse > Create an iterator which generates a flat top pulse waveform.
A flat top pulse waveform is represented by the following equation
Equation for a flat top pulse waveform.
when `(t-φ)%T < τ` and where `T` is the pulse period, `τ` is the pulse duration, `A` is the amplitude, and `φ` is the phase offset. The waveform is `0` otherwise. The coefficients are - `a_0`: 0.21557895 - `a_1`: 0.41663158 - `a_2`: 0.277263158 - `a_3`: 0.083578947 - `a_4`: 0.006947368
## Usage ```javascript var iterFlatTopPulse = require( '@stdlib/simulate/iter/flat-top-pulse' ); ``` #### iterFlatTopPulse( \[options] ) Returns an iterator which generates a flat top pulse waveform. ```javascript var it = iterFlatTopPulse(); // 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`. - **duration**: pulse duration. Must be greater than `2`. Default: `options.period`. - **amplitude**: amplitude. Default: `1.0`. - **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: `0`. - **iter**: number of iterations. Default: `1e308`. 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 = iterFlatTopPulse( 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 = iterFlatTopPulse( opts ); // returns var v = it.next().value; // returns v = it.next().value; // returns 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 // ... ``` 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 = iterFlatTopPulse( 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 v = it.next().value; // returns // ... ``` To translate the waveform to the right, ```javascript var opts = { 'period': 10, 'duration': 5, 'offset': 2 }; var it = iterFlatTopPulse( opts ); // returns var v = it.next().value; // returns 0.0 v = it.next().value; // returns 0.0 v = it.next().value; // returns 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 = iterFlatTopPulse( 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 iterFlatTopPulse = require( '@stdlib/simulate/iter/flat-top-pulse' ); // Create an iterator: var opts = { 'period': 50, 'duration': 25, 'amplitude': 10.0, 'offset': -25, 'iter': 100 }; var it = iterFlatTopPulse( 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/pulse]: https://github.com/stdlib-js/simulate/tree/main/iter/pulse