Video showing undermodulation and overmodulation

Summary

In this video, the creator expresses gratitude to long-term subscribers and discusses the limitations of his equipment. He then delves into a demonstration of amplitude modulation, explaining the concepts of under modulation and over modulation using an oscilloscope. The creator clarifies the importance of modulation percentage in transmitting information and shows the effects of different modulation levels on the signal quality. He also shares his preference for analog oscilloscopes over digital ones and briefly reviews a cheap digital model.

Takeaways

• 🙏 The video creator expresses gratitude to long-term subscribers for their continued support despite the limitations in production quality.
• 🛠 The creator acknowledges having a limited workspace and basic equipment, such as a cheap camera, but makes the best use of what they have.
• 📺 The creator watches videos from their subscribers and gets recommended content on YouTube, which sometimes diverts them from their intended viewing.
• 📡 The video revisits the topic of modulation, specifically addressing the concepts of under modulation and over modulation, which were not clearly explained in a previous video.
• 🔍 The creator is not a modulation expert but shares practical knowledge gained from their work, aiming to clarify what modulation percentages mean in practice.
• 📶 The video demonstrates how different modulation percentages affect the AM waveform, showing the carrier and modulating signals on an oscilloscope.
• 🚫 At low modulation percentages, the audio information can be lost, which is why very low modulation levels are not used.
• 🚨 Over modulation leads to gaps in the waveform, which can cause signal clipping and distortion, hence the importance of avoiding it.
• 🔧 A primitive demodulator is built to remove the carrier and show the effects of over modulation on the audio signal.
• 🔄 The creator compares analog and digital oscilloscopes, expressing a preference for analog scopes but acknowledging the adequacy of digital ones for basic tasks.

Q & A

What is the main focus of the video?

The main focus of the video is to demonstrate and explain the concepts of under modulation and over modulation in the context of amplitude modulation (AM).

Why does the presenter express gratitude to their subscribers at the beginning of the video?

The presenter expresses gratitude to their long-term subscribers for continuing to watch their videos despite the limitations in production quality and resources.

What limitations does the presenter acknowledge in their video production setup?

The presenter acknowledges having a limited size workbench, no access to various cameras or microphones, and using a cheap camera for their videos.

What was the topic of the previous video mentioned in the script?

The topic of the previous video was modulation percentage, specifically discussing AM alignment and the setting of modulation levels.

Why is it important to avoid very low modulation percentages?

Very low modulation percentages can cause the valleys and peaks of the waveform to disappear, resulting in the loss of information, making it inaudible or ineffective for transmission.

What happens when modulation is set to 100% or more?

At 100% modulation or more, gaps appear in the waveform, which can lead to parts of the signal being clipped and lost, causing distortion and signal loss.

What is the purpose of a demodulator as shown in the video?

A demodulator is used to remove the carrier signal from the modulated wave, leaving only the audio information, which can then be amplified and played through a speaker.

How does the presenter demonstrate the effects of modulation?

The presenter uses an oscilloscope to visually demonstrate the waveforms at different modulation levels, showing the effects of under modulation and over modulation.

What is the presenter's stance on digital versus analog oscilloscopes?

The presenter prefers analog oscilloscopes for their work but acknowledges that a cheap digital oscilloscope can be suitable for basic electronics work.

Why might someone choose an analog oscilloscope over a digital one?

An analog oscilloscope might be preferred for its familiarity, ease of use, and real-time display of waveforms without the potential lag or latency that can be present in digital scopes.

What advice does the presenter give regarding the purchase of a digital oscilloscope?

The presenter suggests that the decision to purchase a digital oscilloscope should be based on personal preference and budget, and that the cheapest models may have limitations.