AM radio and FM radio have their own advantages, and neither can replace the other.
Difference: AM is easily interfered, the sound quality is average, FM is not easily interfered, the sound quality is better,
AM does not support two-channel stereo, FM supports,
narrow AM bandwidth, wide FM bandwidth,
The AM frequency is low, the FM frequency is high (the transmit power is small),
Amplitude modulation is simpler than FM modulation, and acceptance is not as troublesome as FM.
AM radio and FM radio have their own advantages, and neither can replace the other.
To understand this problem, you must first understand modulation and demodulation. Modulation—— can be understood as loading the goods on the truck, and the goods here are the voice signals in the broadcast. If the voice signal is not loaded into the truck, he will not travel far. Demodulation —– is to unload the ‘goods’ from the van and play it on the radio, so that the listener can hear the sound.
1. Amplitude modulation
In the figure, a is the truck we just talked about, and b is the goods, that is, the goods we want to deliver (sound). C is the appearance of the truck loaded with goods. The dotted part of C is our goods (sound), which is exactly the magnitude of C. Demodulation is to take out the dotted line part of Figure C, that is, his amplitude, so it is called amplitude modulation. Since the amplitude signal is easily affected by the outside world, the sound quality is not ideal.
2. Frequency modulation
The blue curve in the last picture is the sound waveform we need, and the red one is the graph of the truck full of goods. It can be found that the blue curve is related to the density (frequency) of the red curve. This modulation method is called frequency modulation. , the frequency signal is not easily interfered by the external environment, so compared with AM, FM is a more advanced method, and FM can also be used as a digital modulation method, which is a step further.
AM radio and FM radio have their own advantages, and neither can replace the other.
Difference: AM is easily interfered, the sound quality is average, FM is not easily interfered, the sound quality is better,
AM does not support two-channel stereo, FM supports,
narrow AM bandwidth, wide FM bandwidth,
The AM frequency is low, the FM frequency is high (the transmit power is small),
Amplitude modulation is simpler than FM modulation, and acceptance is not as troublesome as FM.
