braintools.input.triangular

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braintools.input.triangular#

braintools.input.triangular(amplitude, frequency, duration, t_start=None, t_end=None, bias=False)#

Generate triangular wave current input.

Creates a triangular (linear ramping) waveform that linearly increases and decreases between peak values. Useful for testing linear responses and ramp sensitivity.

Parameters:

  • amplitude (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Peak amplitude of the triangular wave. Supports current units.

  • frequency (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Frequency of oscillation. Must be in Hz units.

  • duration (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – Total duration of the signal. Supports time units.

  • t_start (Array | ndarray | bool | number | bool | int | float | complex | Quantity | None) – Time when triangular wave starts. Before this, output is 0. Default is 0.

  • t_end (Array | ndarray | bool | number | bool | int | float | complex | Quantity | None) – Time when triangular wave ends. After this, output is 0. Default is duration.

  • bias (bool) – If True, adds DC offset equal to amplitude (non-negative output). If False, oscillates between -amplitude and +amplitude.

Returns:

current – The triangular wave current array with shape (n_timesteps,).

Return type:

ndarray or Quantity

Raises:

AssertionError – If frequency is not in Hz units.

Examples

>>> import brainunit as u
>>> import brainstate
>>> brainstate.environ.set(dt=0.1 * u.ms)

Simple triangular wave at 5 Hz

>>> current = triangular(
...     amplitude=10 * u.pA,
...     frequency=5 * u.Hz,
...     duration=1000 * u.ms
... )

Slow triangular ramp for I-V curves

>>> current = triangular(
...     amplitude=100 * u.pA,
...     frequency=0.5 * u.Hz,  # 2 second period
...     duration=4000 * u.ms
... )

Triangular wave with positive bias

>>> current = triangular(
...     amplitude=5 * u.nA,
...     frequency=10 * u.Hz,
...     duration=500 * u.ms,
...     bias=True  # Oscillates between 0 and 10 nA
... )

Windowed triangular stimulation

>>> current = triangular(
...     amplitude=8 * u.pA,
...     frequency=2 * u.Hz,
...     duration=3000 * u.ms,
...     t_start=500 * u.ms,
...     t_end=2500 * u.ms
... )

High-frequency triangular wave

>>> current = triangular(
...     amplitude=2 * u.nA,
...     frequency=50 * u.Hz,
...     duration=200 * u.ms
... )

Testing adaptation with slow ramps

>>> current = triangular(
...     amplitude=15 * u.pA,
...     frequency=1 * u.Hz,
...     duration=5000 * u.ms
... )

Notes

  • The wave ramps linearly between -amplitude and +amplitude

  • With bias=True, ramps between 0 and 2*amplitude

  • Peaks occur at 0, 0.5/frequency, 1/frequency, etc.

  • More suitable than sawtooth for symmetric ramping

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