A simple way to distinguish between broadband FM and narrowband FM

Jacktang

A simple way to distinguish between broadband FM and narrowband FM [Copy link]

According to the magnitude of the instantaneous phase deviation of the carrier after modulation, frequency modulation can be divided into wideband frequency modulation (WBFM) and narrowband frequency modulation (NBFM). There is no strict boundary between broadband and narrowband modulation, but it is generally believed that when the maximum instantaneous phase deviation caused by frequency modulation is less than 30°, it is called narrowband frequency modulation. Otherwise, it is called broadband frequency modulation.
Broadband frequency modulation is suitable for applications with high requirements for sound quality, while the sound quality of narrowband frequency modulation is not as good as broadband, but the number of wave stations is more than broadband frequency modulation
. The so-called broadband frequency modulation technology FM wireless broadcasting standard is that the modulation frequency deviation of the high-frequency carrier is 75kHz. The wireless microphone we use is also like this. It has good sound quality and is suitable for transmitting audio signals from 40Hz to 18kHz. Narrowband high frequency is mainly used for wireless voice transmission. The frequency deviation is only a few thousand Hz, the common 3 to 5kHz, which is only suitable for mid-range audio signals from 800 to 3kHz. Narrowband high frequency is widely used in wireless walkie-talkies.

In the early days of radio technology, there was no distinction between narrowband and wideband. Gradually, technologies narrower and wider than the mainstream radio channel bandwidth emerged, so there was a distinction between narrowband and wideband. Of course, in terms of technical difficulty, both narrowband and wideband technologies are more difficult than traditional technologies, and broadcasting is based on traditional technologies.
Under modern digital technology, narrowband channels and spread spectrum broadband channels are mainstream, but narrow and wide are still relative here.
Varactor tubes do not distinguish between broadband and narrowband, let alone "dedicated". The channel bandwidth is mainly determined by the circuit structure.

alan000345

Simple and clear

okhxyyo

Thank you for sharing ~ I will learn from it