Frequency Division of high-frequency circuits and low-frequency circuits

13:55:34
Frequency Division of high-frequency circuits and low-frequency circuits
High-Frequency Division:
Extremely low frequency elf less than 3 kHz
Very Low Frequency VLF 3-30 kHz
Low Frequency lf 30-300 kHz
Medium Frequency MF 300-3 MHz
High-frequency HF 3-30 MHz
300 MHz (Television 1---12 channel)
Ultra high frequency UHF 300-3 GHz (TV with 13 channels or above)
Uhf shf 3G-30 GHz
It is also divided as follows:
Frequency is divided according to regulations to facilitate professional communication languages:
Ultra-low frequency: 0.03-300Hz
Extremely low frequency: 300-3000Hz (audio)
Very Low Frequency: 3-300 kHz
Long Wave: 30-300 kHz
Medium Wave: 300-3000 kHz
Transient wave: 3-30 mb
Very High Frequency: 30-MB
UHF:-MB
High frequency: 3-30g
Extremely high frequency: 30-300g
Far Infrared: 300-3000g I am working on an MP3 player recently. The crystal oscillator is 12 M. As mentioned above, it should be of high frequency. The grounding problem of positive headaches can also be solved. Because Generally, the frequency is below 1 MHz, and one point of ground can be used; when the frequency is higher than 10 MHz, multi-point grounding is adopted; in 1 ~ One point of grounding is available between 10 MHz, and multiple points of grounding are also available.