---
title: Constant (v0.46)
description: API reference for qiskit.pulse.library.Constant in qiskit v0.46
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/0.46/qiskit.pulse.library.Constant_class.rst
---

# Constant

*class* `qiskit.pulse.library.Constant(duration, amp, angle=None, name=None, limit_amplitude=None)`

[GitHub](https://github.com/qiskit/qiskit/tree/stable/0.46/qiskit/pulse/library/symbolic_pulses.py)

Bases: [`object`](https://docs.python.org/3/library/functions.html#object)

A simple constant pulse, with an amplitude value and a duration:

$$
f(x) = \text{amp}\times\exp\left(i\text{angle}\right)    ,  0 <= x < duration
f(x) = 0      ,  elsewhere
$$

Create new pulse instance.

**Parameters**

- **duration** – Pulse length in terms of the sampling period dt.
- **amp** – The magnitude of the amplitude of the square envelope. Complex amp support is deprecated.
- **angle** – The angle of the complex amplitude of the square envelope. Default value 0.
- **name** – Display name for this pulse envelope.
- **limit\_amplitude** – If `True`, then limit the amplitude of the waveform to 1. The default is `True` and the amplitude is constrained to 1.

**Returns**

ScalableSymbolicPulse instance.

## Attributes

### alias

Default value: `'Constant'`