# 3. ALIEN VOICE EFFECT

In this exercise, we will create a simple voice effect, namely taking the microphone's input signal and producing an "alien" version of it. During the implementation, we will come across a few limitations that arise when trying to realize digital signal processing (DSP) in real-time.

In [Section 3.1](https://lcav.gitbook.io/dsp-labs/alien-voice/effect_description), we will explain the effect that we will be implementing. In [Section 3.2](https://lcav.gitbook.io/dsp-labs/alien-voice/dsp_tips), we will discuss some important points that need to be considered when implementing real-time DSP. In [Section 3.3](https://lcav.gitbook.io/dsp-labs/alien-voice/python), we propose a Python framework for simulating a real-time environment with your laptop's sound card the [`sounddevice`](http://python-sounddevice.readthedocs.io/) library. Finally, we will guide you through the implementation on the STM32 board in [Section 3.4](https://lcav.gitbook.io/dsp-labs/alien-voice/implementation).

As in the previous chapter, text contained in highlighted boxes, as shown below, will require ***you*** to determine the appropriate solution and implementation.

{% hint style="info" %}
TASK: This is a task for you!
{% endhint %}

```
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```

[Source](http://www.asciiworld.com/-Aliens,128-.html).