One of the pins is programmed to produce a constant 1000 KHz square wave using PIO. The main program then turns the PIO on and off at the intended frequency. e.g. to emit an A4 pitch (440 Hz), it turns the 1000 KHz square wave on and off 440 times a second. To the radio receiver, this means a 440 Hz square wave audio. Using this technique, it emits the well-known Shave and A Haircut melody on a loop.
DocBook 4 XSLT stylesheets.
，这一点在搜狗输入法2026中也有详细论述
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Forbidden tags are removed: meta, title, iframe, object, embed, applet, frame, frameset, base, svg, geolocation, permission. SVG tag has quite a lot of attack vectors, which is why it was banned. People could still use svg files in img tag though. Iframes were banned simply for performance reasons.
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