具有正弦波和吉他效果踏板的实验！

I was approached with the idea to prototype an “audio adapter” for theAnalog Discovery 2oscillos显示音频信号cope and being the audio nerd I am, I was all about it. I looked to theBNC Adapterfor inspiration for the PCB design, since most of its aspects I could transfer directly to my audio adapter design. What I noticed was not only does it have BNC connectors for theWaveformsScope, but it also has connectors for the Wavegen output. Cool, I thought.

我认为最通用的音频插孔是3.5mm的电缆插孔。任何其他类型的音频输出都应适应于此。我想到了Wavegen仪器在需要参考信号的应用中如何有助于音频分析，并决定我还将这些输出也包括在3.5mm的插孔中。我想到要通过各种吉他踏板来看看示波器上会发生什么，这将是多么有趣。因此，在我的董事会被捏造和组装后，我做到了。

I wanted to try different types of effects rather than multiple examples of a single type so I grabbed distortion, chorus, and reverb effects pedals. I had only pieces of ideas of what to expect with these different effects so I tried all sorts of settings with all sorts of Waveforms tools until I found what settings maximized the visual effect on the scope but what other instruments provided interesting visual analysis results. Keep in mind, all of the analysis I did was visual and motivated by pure curiosity. I used a sine wave at 1kHz and 500mV to simulate a frequency in the range of an electric guitar and an approximated maximum output voltage for all tests. I have included screenshots from Waveforms where it made sense but I also made short videos from Waveforms and included those after all the screenshots for each pedal. Some things are better described with video (like the reverb effect.)

Using an Electro-Harmonix Neo Chorus with the “depth” switch in the upright position (largest amplitude of modulation), turning the “rate” knob to about the 3 o’clock position, then zooming out the time step on the Scope channel I was able to observe (although subtle) an envelope being applied to the input sine wave!

我想看看是否可以使用另一个工具将其可视化更多，因此我打开了记录器并记录了该频道的直流值。由于调制引起了动态直流的偏移，因此直流图的周期性型行为在我将“速率”旋钮转换为更高的调制速率时的频率增加！它确实正在调节！这应该帮助那些学习连续时间线性系统的学生对数学的收听有所不同。

接下来是我的朋友达伦·蔡斯（Darren Chase）为我建造的失真踏板，作为1960年代至70年代的一堆图形小说的交易。根据我当时的要求，它是Fulltone OCD Overdrive的克隆。只要将踏板上的踏板转换为三角波，即使所有参数都拨动了。然后，将“音调”旋钮升起，将不对称性引入三角形波并将“失真”旋钮抬起，导致“鲨鱼鳍状”边缘出现在每个半循环的领先边缘。

我弹出了打开频谱工具，以查看频域中的失真。我注意到，转动踏板的偶数和奇怪的谐波，奇怪的谐波占主导地位。打开“音调”旋钮似乎平均增加了所有谐波的幅度，而“变形”旋钮似乎只会增加偶数谐波的幅度。有趣的是，我想。

Finally, I really wanted to see what I could generate with a reverb pedal, if anything. I used an Electro-Harmonix Holy Grail Plus. After messing with the different types of reverb and the other knobs for a bit, I was able to exaggerate a peculiar effect that I noticed and did not expect at all. On the “Hall” setting, the pedal is trying to emulate the echo characteristics of a large concert hall or something similar.

使用此设置，我从“混合”（输入信号的加权和加工信号的加权总和）和“混合和衰减时间中处理信号的幅度”开始，然后将“混合”全部旋转上升的方式是将“量”​​旋钮一直上升到上升，我注意到正弦波的振幅不仅会增长，而且峰会表达出一种“抑制调制”。Trippy，我想。请注意，我很快就抬起了两个旋钮，但随后将它们一直保持在不再调整的情况下。在两个旋钮都迅速上升然后独自一人时，“抑制调制”正在发生。

I remembered the Logger instrument and how it helped me with the chorus pedal, so I did the same experiment using the Logger and captured a very pretty ringing behavior! I would have never guessed I was going to see something like that using a reverb pedal, although typical use of a reverb pedal does not involve such drastic dynamics with those parameters.

我很好奇这些类型的吉他效果踏板的其他类型和示例在放入示波器，频谱分析仪或数据记录器时可以做什么。没有什么比将乐趣带到一个新的水平并在不同的眼光下学习一两件事了。如果您好奇地在范围内范围范围Waveforms, using anAnalog Discovery 2，或有关我的“音频适配器”的问题，请发表评论！谢谢！