The Tech Blog

Common Voice Project

Posted under Technology on September 18th, 2022 by Amaldev

This is a slight deviation from usual posts. I was exploring speech recognition for edge devices and happened to run across the open-source Common Voice Project from Mozilla(Firefox) team. Everyone in tech should know about this initiative. Common Voice is a massive multilingual collection of recorded speech for AI-related voice training. It’s entirely open-sourced. ie) The raw datasets, code bases and even the ML models generated from them. The Speech-To-Text engine which was implemented is called the Mozilla DeepSpeech and it’s based on a 2014 DeepSpeech paper from Baidu Search Engine. (DeepSpeech and DeepSpeech2 are great papers if you want to read about their technical gory details). I have linked it below.

To date, the project has recorded over 20,000 hours of data in more than 96 languages across the world. That’s pretty large. Of the recorded data, more than 15,000 hours are validated. The beautiful part is that the entire validation is crowd-sourced. Meaning folks across the world spend a couple of minutes here and there to double-check the recorded data and see if the transcription of these many hours of data is actually correct.

Having such a massive database will always help researchers develop great speech recognition applications going ahead. My sincere request to everyone reading this would be to go the link below and spend maybe 3-5mins maybe on a weekly basis to help with the recording or validation. Whenever you are free or bored. The UI is very simple and easy to use. You just hear the audio and click if the said audio content matches the written text below it. Kinda like a captcha for audio. Or take time to record/validate in your local language. If even a few of you contribute it will greatly help out extending human knowledge. This is one open-source project which can massively impact the future of speech recognition.

Links:

https://commonvoice.mozilla.org/

https://github.com/mozilla/DeepSpeech

https://arxiv.org/pdf/1412.5567.pdf

PS: Fun fact there are only 17hrs recorded Hindi audio on the platform whereas English tops at 3100 hours of recorded data.

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Flipped Capacitors

Posted under Back to Basics, Educational, Product Design, Technology on September 11th, 2022 by Amaldev

Most electronic design engineers know SMD capacitor parts come in the “standard” sizes of let’s say 1206, 0805, 0603,0402, 0201 etc. The common element of these parts is that their size is longer along terminals(between 2 pads you actually solder) than along the width of the part. Most times width of the part is half the length. There is a different class of capacitors which are wider than long. These are called flipped or reverse geometry capacitors. So the sizes will be 0612, 0508, 0306, 0204 etc. (To be honest, you might not find a flipped capacitor for every “standard” size capacitor though)

Why do we want to use a flipped capacitor? In one of my older posts, I explained that a capacitor in real life is not a capacitor by itself. It has an equivalent series resistance(ESR) and inductance(ESL). For an ideal capacitor, we would want to have ESRs and ESLs to be zero. Since there is an ESL in a capacitor, you usually see a V-shaped impedance curve with frequency in capacitor datasheets. The impedance value keeps getting low till a point and then it increases due to ESL. Here is where flipped capacitors come into the picture. Flipped capacitors are designed specifically to reduce ESL. When you flip the width and length dimensions of a capacitor, it reduces the soldering pad distances(or the length). Lower travel length means lower inductance and lower conductor length(Not to complicate it more, loop area also reduces, which is a good thing). So current needs to travel a shorter distance. A wider flipped capacitor effectively can have an impedance curve which is similar to 3-4 same standard-size capacitors. That means overall lower BOM count and layout space is lesser. For these reasons, these wider capacitors are starting to gain acceptance in the PCB design space.

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