关于噪声温度noise figure

Occupied bandwidth,  4.7 MHz
Noise figure 6 dB
Noise floor -108 dBm/MHz
Noise power in bandwidth -101.28 dBm
SNR (QPSK ½, AWGN) 3.7 dB
Sensitivity, P -98 dBm
这里的参数6dB是和谁比出来的啊，怎么信噪比又成3.7dB了呢

和Noise floor啊
Noise figure的意思是由于接受机的电子电路对噪声有6db的放大关系
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Noise figure(factor)=Input signal-to-Noise/Output Signal-to-Noise
I think u can find a formula for SNR,check it from the books

谢谢阿

antenna as an example
the input noise at the antenna will be amplified at the output of
antenna, then there is a ratio between the previous and following nosie power
I       t is noise figure...