The importance of the transmit power of the SMB RF connector is that the transmitter's signal needs to be spatially faded before it can reach the receiver, so the higher the transmit power means the farther the communication distance. So, do we want to pay attention to SNR? For example, if our transmit signal has a poor SNR, is the signal SNR arriving at the receiver also poor?

    This involves the concept that the natural noise floor. We assume that the fading of space is the same for both signal and noise (actually not, the signal can be coded to resist fading and noise is not good) and it acts like an attenuator, then we assume a spatial fading of -200dB and a transmitted signal bandwidth of 1Hz. , power 50dBm, signal to noise ratio 50dB, what is the SNR of the receiver received signal?

    The power of the SMB connector received by the receiver is 50-200=-150Bm (bandwidth 1Hz), and the noise of the transmitter is 50-50=0dBm through spatial fading. The power reaching the receiver is 0-200=-200dBm (bandwidth 1Hz)? At this time, this part of the noise has been "submerged" under the natural noise floor of -174dBm/Hz. At this time, we calculate the noise at the receiver inlet, and only need to consider the "basic component" of -174dBm/Hz, this is true in most cases of communication systems.