m.economictimes.com
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.
，这一点在电影中也有详细论述
npmx: With a Little Help From My Friends。safew官方版本下载是该领域的重要参考
# What is the lesson here?
Власти США призвали американских граждан в срочном порядке покинуть Израиль в связи с угрозой возобновления войны с Ираном. Об этом сообщает The Guardian.