Most of you guys should have used Bluetooth headsets. Bluetooth headset keep us away from annoying wires and make it easier for us to use our phones. Do you want to learn more about it? To help you better understand the basics of Bluetooth headset, the Bluetooth Headset Basics column is online.
Today, let's talk about how the Bluetooth headset works.
First, the phone will establish a data transmission channel with the Bluetooth headset, which is the Bluetooth connection. The phone then decodes the audio file to generate an audio signal. In this case, the audio signal is presented as an analog signal. The analog signal is then quantized into the digital signal based on PCM (Pulse-code modulation). That is, as shown in the figure below, the red analog signal is turned into the blue digital signal.
Then, the audio data is compressed and packed according to different Bluetooth audio encodings, then modulated to a specific 2.4 GHz frequency and transmitted to the Bluetooth headset. Modulation can be understood as processing audio signals and then placing them on the electromagnetic wave of 2.4 GHz.
Then, the chip on the headset side demodulates the received electromagnetic waves into digital signals, and then restores the digital signals to analog signals (that is, audio signals). Finally, the analog signal is amplified and played by the sounding unit of the headset, and then we hear the sound.
The whole process can be shown by the following picture:
Professional vocabulary explanation
PCM: Pulse Code Modulation. In the PCM process, the transmitting end samples, quantizes, and encodes the input analog signal, and uses the binary coded number to represent the amplitude of the analog signal; the receiving end then restores these codes to the original analog signal.
