Receiver Sensitivity (Rx Sensitivity)
Receiver sensitivity is the lowest input level at which a packet can still be decoded at a defined error rate, and it is written in negative dBm. Sub-GHz FSK receivers typically report values in the −125 to −130 dBm range. The more negative the number, the better the receiver: a 10 dB improvement means roughly 3 times the distance in free space.
Sensitivity alone is not a quality label; it cannot be compared without stating at which data rate and at which bit error rate it was measured. The same chip reports a few dB better sensitivity at a lower data rate.
- As the data rate drops the filter window narrows, noise decreases and sensitivity improves.
- When the noise floor rises the datasheet sensitivity becomes invalid; what matters in the field is not the absolute level but the signal-to-noise ratio.
- For a link to be established the received level should stay clearly above the sensitivity, typically with a 10–20 dB safety margin.
These values are general chip data and are not attributed to a specific product. The range figures of AXI sets (about 100 m for SF100/SF200, about 150 m for ST100/ST200, 100 m for HCT400/HCT402) are given for open-area, line-of-sight conditions; since effective sensitivity drops in enclosed and noisy environments, these distances shorten.
Context in which this term is used: Wireless remote control installation: pairing, relay, safety