Use the calculator to estimate receiver sensitivity (minimum input signal power) in dBm. For the Basic tab, enter the system noise floor (dBm, over the receiver bandwidth) and the required SNR (dB). For the Bandwidth tab, sensitivity is computed from bandwidth, temperature, noise figure, and required SNR.
Related Calculators
- Average Noise Level Calculator
- Antenna Loop Calculator
- Front To Back Ratio Antenna Calculator
- Power Loss Calculator
- All Physics Calculators
Receiver Sensitivity Formula
RS = N_{floor} + SNR_{req}\\
N_{floor} = -174 + 10\log_{10}(BW) + NF + 10\log_{10}(T/290)Variables:
- RS is the receiver sensitivity (minimum input signal power) in dBm
- Nfloor is the system noise floor in dBm (integrated over BW)
- SNRreq is the required signal-to-noise ratio (or a similar quality criterion such as SINAD) in dB
- BW is the receiver/noise bandwidth in Hz
- NF is the receiver noise figure in dB
- T is noise temperature in kelvin (K); 290 K is the standard reference temperature
In most receiver specifications, sensitivity is reported as an absolute power level (dBm). The common thermal-noise reference is −174 dBm/Hz at 290 K; bandwidth and temperature set the thermal noise, then noise figure and the required SNR (or SINAD/BER requirement) set the sensitivity threshold.
How to Calculate Receiver Sensitivity?
The following steps outline how to calculate the Receiver Sensitivity.
- Determine the receiver/noise bandwidth, BW (Hz), and the noise temperature, T (K) (often 290 K for room temperature reference).
- Determine the receiver noise figure, NF (dB).
- Determine the required SNR (dB) (or the applicable criterion such as SINAD/BER that your system uses).
- Compute the system noise floor: Nfloor = −174 + 10·log10(BW) + NF + 10·log10(T/290) (dBm).
- Compute receiver sensitivity: RS = Nfloor + SNRreq (dBm), then check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Noise figure (NF) = 6 dB, bandwidth (BW) = 12.5 kHz, required SNR = 12 dB, temperature (T) = 290 K
Thermal noise floor ≈ −174 + 10·log10(12500) = −133.03 dBm, so sensitivity RS ≈ −133.03 + 6 + 12 = −115.03 dBm
FAQs about Receiver Sensitivity and Related Concepts
What is Receiver Sensitivity and why is it important?
Receiver sensitivity is the minimum input signal power (typically specified in dBm) needed to meet a defined performance target (for example a required SNR, SINAD, or BER). It is important because it strongly affects the achievable range and reliability of a communication link.
How does the noise floor affect Receiver Sensitivity?
A higher noise floor (a less negative dBm value) means the receiver needs a stronger signal to achieve the same quality target, which is worse sensitivity. Lowering the noise floor improves sensitivity.
What is the difference between Receiver Sensitivity and Signal-to-Noise Ratio (SNR)?
Receiver sensitivity is an absolute threshold power at the receiver input (dBm). SNR is a relative ratio (dB) comparing the desired signal to noise. Sensitivity is often computed from the noise floor plus the required SNR (or a related criterion like SINAD/BER).
Can Receiver Sensitivity be improved? If yes, how?
Yes. Common ways include reducing receiver noise figure (better LNA/front-end design), narrowing the receiver noise bandwidth when possible, reducing system/interference noise, improving antenna/system losses, or using more robust modulation/coding that reduces the required SNR for a given BER.
