Question

Please discuss how would spectrum analyzer can affect, when simulating under rf board especially sensitivity.

Answer 1

One of the primary uses of a spectrum analyzer is to search out and measure low-level signals. The sensitivity of any receiver is an indication of how well it can measure small signals. A perfect receiver would add no additional noise to the natural amount of thermal noise present in all electronic systems, represented by

kTB

k=Boltzman's constant,

T=temperature, and

B=bandwidth.

In practice, all receivers, including spectrum analyzers, add some amount of internally generated noise. Spectrum analyzers usually characterize this by specifying the displayed average noise level (DANL) in dBm, with the smallest RBW setting. DANL is just another term for the noise floor of the instrument given a particular bandwidth. It represents the best-case sensitivity of the spectrum analyzer, and is the ultimate limitation in making measurements on small signals. An input signal below this noise level cannot be detected. Generally, sensitivity is on the order of -90 dBm to -145 dBm.It is important to know the sensitivity capability of your analyzer in order to determine if it will adequately measure your low-level signals.