1 System composition: RF-->ADC---->FFT Assuming that the signal passes through these three modules, both the clock and the filter are ideal, and the Spurs have only three-order intermodulation components.
2 RF: Input noise ni, gain g, noise figure F, output impedance RS, input third-order cutoff point IIP3 (3rd order intercept) Bandwidth B input 1dB compression point IP1 (1 DB compression)
IP3 = P1 + 9.64
2 ADC: Input impedance RL, conditioning circuit gain of 0, reference voltage v=1v (input signal peak V/2) significant number of bits enob, sampling frequency FS,
3 FFT length n, Window factor = main lobe width/rectangular window main lobe width
Signal to noise ratio threshold 14dB
Calculates the noise power of the indicator RF output. Sensitivity. Dynamic range. The noise power after FFT processing. Sensitivity. Dynamic Range
The RF output noise floor is determined by the output noises and spurious power
RF output Noise: No = GBNI=KT0BFG
The spurious power of the maximum 3 order intermodulation in the RF output band:
The ADC assumes that the impedance is matched, the conditioning circuit has no gain, and only the quantization error is the other ideal
Quantization noise power of the ADC at full scale: nb= input ADC Power -6.02xenob-1.76
FFT post-Video Bandwidth BV = fs/n
Receiver indicators-noise, sensitivity, dynamic range