1 / 4

Receiver Sensitivity

Receiver Sensitivity. Sensitivity describes the weakest signal power level that the receiver is able to detect and decode Sensitivity is dependent on the lowest signal-to-noise ratio at which the signal can be recovered Different modulation and coding schemes have different minimum SNRs

vian
Télécharger la présentation

Receiver Sensitivity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Receiver Sensitivity • Sensitivity describes the weakest signal power level that the receiver is able to detect and decode • Sensitivity is dependent on the lowest signal-to-noise ratio at which the signal can be recovered • Different modulation and coding schemes have different minimum SNRs • Range: <0 dB to 60 dB • Sensitivity is determined by adding the required SNR to the noise present at the receiver • Noise Sources • Thermal noise • Noise introduced by the receiver’s pre-amplifier

  2. Thermal Noise • Thermal Noise = N = kTB (Watts) • k=1.3803 x 10-23 J/K • T = temperature in Kelvin • B=receiver bandwidth • So Thermal Noise can be expressed by following formula N = -228,6 dBw + 10 log T + 10 log B • Thermal noise is usually very small for reasonable bandwidths • Noise introduced by the receiver pre-amplifier • Noise Factor = Noise Figure = SNRin/SNRout (positive because amplifiers always generate noise)

  3. Receiver Sensitivity Calculation • The smaller the sensitivity, the better the receiver • Sensitivity (W) = kTB * NF(linear) * minimum SNR required (linear) • Sensitivity (dBm) =10log10(kTB*1000) + NF(dB) + minimum SNR required (dB)

  4. Sensitivity Example • Example parameters • Signal with 200KHz bandwidth at 290K • NF for amplifier is 1.2dB or 1.318 (linear) • Modulation scheme requires SNR of 15dB or 31.62 (linear) • Sensitivity = Thermal Noise + NF + Required SNR • Thermal Noise = kTB = (1.3803 x 10-23 J/K) (290K)(200KHz) = 8.006 x 10-16 W = -151dBW or -121dBm • Sensitivity (W) = (8.006 x 10-16 W )(1.318)(31.62) = 3.33 x 10-14 W • Sensitivity (dBm) = -121dBm + 1.2dB + 15dB = -104.8dBm • Sensitivity decreases when: • Bandwidth increases • Temperature increases • Amplifier introduces more noise

More Related