Why does the computer headset have noise when the mobile phone receives short messages?

This phenomenon is called TDMA noise, because the Global System for Mobile Communications (GSM) uses eight physical channels every 200KHz channel, that is, time division multiplexing of eight users on the same frequency, which can also be understood as time division multiple access (TDMA). Each time slot is 0.577us, which is assigned to one user, so each frame is 0.577× 8 = 4.615 ms.

On the other hand, the radio frequency power amplifier (PA) of mobile phone will send out a signal every 4.6 15ms, which includes the 2.0G GSM signal of 900MHz/ 1800MHz or 1900MHz and the envelope of PA. The "buzzing" sound we hear is the envelope noise generated by PA during transmission, and its corresponding frequency is 2 16.8Hz. Since the auditory frequency range of human ears is 20 Hz ~ 20 Hz, 2 16.8Hz is indeed within the auditory range of human ears. If the mobile phone makes a phone call or sends a text message, the landline microphone or computer headset will make a "buzzing" sound. ("Technology Life" Weekly)

This article comes from: Technology Life Weekly.