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

# qiskit.pulse.library.SechDeriv

`qiskit.pulse.library.SechDeriv(duration, amp, sigma, angle=0.0, name=None, limit_amplitude=None)`

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

An unnormalized sech derivative pulse.

The sech function is centered around the halfway point of the pulse, and the envelope of the pulse is given by:

$$
f(x) = \text{A}\frac{d}{dx}\left[\text{sech}
\left(\frac{x-\mu}{\text{sigma}}\right)\right]  ,  0 <= x < duration
$$

where $\text{A} = \text{amp} \times\exp\left(i\times\text{angle}\right)$, $\mu=\text{duration}/2$, and $d/dx$ is a derivative with respect to x.

**Parameters**

- **duration** ([*int*](https://docs.python.org/3/library/functions.html#int)  *|*[*ParameterExpression*](/docs/api/qiskit/0.46/qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")) – Pulse length in terms of the sampling period dt.
- **amp** ([*float*](https://docs.python.org/3/library/functions.html#float)  *|*[*ParameterExpression*](/docs/api/qiskit/0.46/qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")) – The magnitude of the amplitude of the pulse (the value of the corresponding sech function at the midpoint duration/2).
- **sigma** ([*float*](https://docs.python.org/3/library/functions.html#float)  *|*[*ParameterExpression*](/docs/api/qiskit/0.46/qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")) – A measure of how wide or narrow the corresponding sech peak is, in terms of dt; described mathematically in the class docstring.
- **angle** ([*ParameterExpression*](/docs/api/qiskit/0.46/qiskit.circuit.ParameterExpression "qiskit.circuit.parameterexpression.ParameterExpression")  *|*[*float*](https://docs.python.org/3/library/functions.html#float) *| None*) – The angle in radians of the complex phase factor uniformly scaling the pulse. Default value 0.
- **name** ([*str*](https://docs.python.org/3/library/stdtypes.html#str) *| None*) – Display name for this pulse envelope.
- **limit\_amplitude** ([*bool*](https://docs.python.org/3/library/functions.html#bool) *| None*) – 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.

**Return type**

*ScalableSymbolicPulse*