Receiver Sensitivity / MDS & SFDR
Finds a receiver's sensitivity — the minimum detectable signal (MDS) — from its noise bandwidth, noise figure, and the SNR your demodulator needs. It first computes the thermal noise floor referred to the input, adds the noise figure and the required SNR, and (optionally) uses the input third-order intercept to give the spurious-free dynamic range (SFDR).
Equations & Parameters ▸
\(P_{\text{floor}} = -174\ \text{dBm/Hz} + 10\log_{10}B + NF \qquad \text{MDS} = P_{\text{floor}} + \text{SNR}_{\min}\)
\(\text{SFDR} = \tfrac{2}{3}\big(\text{IIP3} - P_{\text{floor}}\big)\)
\(\text{SFDR} = \tfrac{2}{3}\big(\text{IIP3} - P_{\text{floor}}\big)\)
| B | Noise bandwidth (Hz). The −174 dBm/Hz term is kT₀ at T₀ = 290 K. |
| NF | Cascaded noise figure of the receiver (dB). |
| SNRmin | Signal-to-noise ratio the demodulator needs for the target BER/quality (dB). |
| IIP3 | Input third-order intercept point (dBm), optional. Sets the top of the spurious-free range. |
| SFDR | Spurious-free dynamic range: the input range over which third-order intermodulation products stay below the noise floor. |
References: B. Razavi, RF Microelectronics, 2nd ed., Prentice Hall, 2012. · U. L. Rohde & M. Rudolph, RF/Microwave Circuit Design for Wireless Applications, 2nd ed., Wiley, 2013.
Inputs
Hz
Channel/IF bandwidthdB
Receiver NFdB
Demod thresholddBm
For SFDRResults
Sensitivity
Noise floor—
Sensitivity / MDS—
Dynamic range
SFDR—
kT₀B in band—
Diagram