用于通道探测的VNA噪声水平

取决于您使用的参数。
如果您使用带有一对天线的S21，则测量是相对测量，您需要将距离损失归一化（根据您拥有的天线增益）。
所以通常你会使用一些标准增益天线并测量S21。
假设范围损耗为30 dB，那么本底噪声将是您所选带宽下VNA的动态范围减去范围损耗。
假设VNA的动态范围规格为140 dBc。
这通常是10 Hz BW和最大功率。
将噪声基底的变化计算为10 log（IFBW / 10），因此，如果您处于100 kHz IF BW，则会有10log10（10e4）或40 dB更差，因此100 dB，减去30的范围损失并结束
最高-70 dB本底噪声（通常表示为rms）。



     以下为原文

  Depends upon what parameter you are using. If you are using S21 with a pair of antennas, then the measurement is a relative measurement and you need to normalize out the range-loss (according the antenna gain that you have).  So normally you would use some standard gain antennas and measure S21. Suppose the range loss is 30 dB, then the noise floor will be the dynamic range of the VNA at your chosen bandwidth minus the range loss.  Suppose the VNA has a dynamic range spec of 140 dBc.  This is typically at a 10 Hz BW and max power.  Compute the change in noise floor as 10 log (IFBW/10) so if you are at 100 kHz IF BW, you would have 10log10(10e4) or 40 dB worse, so 100 dB, subtract off the range loss of 30 and you end up with -70 dB noise floor (typically expressed as rms).