Calculate receiver sensitivity in dBm from bandwidth, noise figure and required SNR, or from a known noise floor, with optional margin and temperature.

The noise (channel) bandwidth of the receiver, e.g. 12.5 kHz for narrowband FM or 20 MHz for Wi-Fi.

The signal-to-noise ratio your demodulator needs (or SINAD/Eb/N0-based equivalent). It can be negative for spread-spectrum links.

Margin and temperature
Extra allowance for losses. Blank means 0 dB.

Blank means the standard 290 K reference (โˆ’174 dBm/Hz).

Related Calculators

Receiver Sensitivity Formula

RS = Nfloor + SNRreq\ Nfloor = - 174 + 10logโ‚โ‚€(BW) + NF + 10logโ‚โ‚€(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 โˆ’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.

  1. Determine the receiver/noise bandwidth, BW (Hz), and the noise temperature, T (K) (often 290 K for room temperature reference).
  2. Determine the receiver noise figure, NF (dB).
  3. Determine the required SNR (dB) (or the applicable criterion such as SINAD/BER that your system uses).
  4. Compute the system noise floor: Nfloor = โˆ’174 + 10ยทlog10(BW) + NF + 10ยทlog10(T/290) (dBm).
  5. 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 โ‰ˆ โˆ’174 + 10ยทlog10(12500) = โˆ’133.03 dBm, so sensitivity RS โ‰ˆ โˆ’133.03 + 6 + 12 = โˆ’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.