[All content typed by hand] The previous person’s answer has been more detailed about Hexuan’s software technology, so I won’t go into details. Hexuan is an old software and hardware technology, which has long been eliminated on mobile phones and has been replaced by MP3, etc. Multimedia new software and hardware technology instead!
1. Let me talk about the comparison between modern audio technology and harmony. For example, "harmony" is like music box music, or music played by multiple music boxes, technology The principle is similar to that of a music box.
Nowadays, mobile phone MP3 has richer sound content, not just one tune for each track, so the audio decoding chip is used to decode and control the current through the PA (power amplifier) The size and waveform push the speaker's electromagnetic coil to work and play the sound.
The chord only has a small amount of audio data, so it is relatively monotonous. The more chords, the better the sound will be. (Except for the buzzer, the speaker You can also play and rotate, which has nothing to do with the hardware. The speaker is a more professional vibration and sound device, but very old mobile phones are simple buzzers or speakers).
2. Old mobile phones use "and" The main reason for "spin" is that the hardware did not use a dedicated audio codec chip at that time, but its own processor speed was low and could not keep up with the decoding speed of hundreds of Kb per second. At the same time, it had to handle many functions, so it could only play the amount of data. It's a very small piece of music like a chord. From the perspective of our mobile phone driver engineers, its software control is as simple as controlling the gpio port. Just pull the level up and down and you can play it (just an example, it's actually a little bit better than this). Complex point).
3. Harmony hardware and hardware principles:
Buzzer (or speaker), playing a scale is an audio technology with the same power and different spectrum. Popular In other words, it means playing music of different scales with the same pitch (loudness), and the loudness is the same. The buzzer is a very simple vibrating sound device. It does not have a speaker diaphragm, so it can only play simple sounds.
Multi-chord is a technology that plays multiple audios with low power spectrum. 8-chord is 8 tracks, and each of the 8 tracks has its own loudness. This kind of music is far from the complicated technology of audio such as MP3. .
Synchronization is a technology used on old or simple electronic devices (*such as electronic greeting cards, a piece of paper and a buzzer, and a rice cooker that will sound when it is cooked, and The little yellow car ofo and the festival festival performers such as Merry Christmas and Happy New Year are all buzzers). When mobile phones first came out, they were called feature phones. This is also the reason why they were not smart phones. At that time, the multimedia technology was weak and had no scalability. . Old mobile phones can only play harmonious music. Because they do not use audio decoding chips, they cannot decode MP3, or the processor speed is low and it is difficult to quickly decode a large amount of audio data. They cannot play the huge music data (each file) in MP3 and other files. Tens of kilobytes or even hundreds of kilobytes of music data per second, and the encoding technology of recording has a larger amount of data. Those who are professional in music technology know the PCM format (pure music pulse signal). This is the real original uncompressed content of recording. The amount of data can reach more than 1M per second. A song takes up to 200MB~1G of space in 3 minutes. After the format is converted and compressed, it becomes a music file such as MP3).
Hexuan has long been MP3 and MP3 and other multimedia decoders have been replaced. Therefore, Android has long ago not needed Hexuan. The hardware technology of Hexuan is a buzzer. The principle is similar to a music box (the metal protrusions on the rolling wheels will sequentially move the metal Shrapnel, shrapnel makes sound).
4. If you have seen this, congratulations, I will tell you a technology, the principle of the moving iron earphone, the moving iron earphone is actually a larger buzzer conduction The diaphragm is actually a little more complicated than what I said, but the principle is like this. The magnetic induction coil of the speaker is replaced by the magnetic induction vibrator, and the larger area of ??the diaphragm structure also disappears.
Author: qiancheng - Huayou Laochai (Lao Jackal)
Date: 20180103