RFM92 Datasheet, PDF (86/126 Pages) List of Unclassifed Manufacturers – Low Power Long Range Transceiver Module

RFM92W/93W V3.0
Towards
-125 dBm
G1
AgcStep1
AgcStep2
AgcStep3
G2
G3
AgcStep4
G4
AgcStep5
G5
Pin [dBm]
G6
Higher Sensitivity
Lower Linearity
Lower Noise Figure
Figure 43. AGC Steps Definition
The AGC reference power level is determined as follows:
AGC Reference [dBm]=-174 dBm + 10 * log(2 * RxBw) + SNR + AgcReferenceLevel
with SNR = 8 dB (considered a fixed value).
A detailed description of the receiver setup to enable the AGC is provided in section 9.3.
Lower Sensitivity
Higher Linearity
Higher Noise Figure
5.5.4. RSSI in FSK/OOK Mode
The RSSI provides a measure of the incoming signal power at RF input port measured within the receiver bandwidth. The
signal power is available in RssiValue. This value is absolute in units of dBm and with a resolution of 0.5 dB. The formula
below relates the register value to the absolute input signal level at the RF input port:
RssiValue = −2 ⋅ RF level [dBm]+ RssiOffset [dB]
The RSSI value can be compensated to take into account the loss in the matching network or even the gain of an
additional LNA by using RssiOffset. The offset can be chosen in 1 dB steps from -16 to +15 dB. When compensation is
applied the effective signal strength is read as follows:
RSSI [dBm] = − ^RssiValue
2
The RSSI value is smoothed on a user defined number of measured RSSI samples. The precision of the RSSI value is
related to the number of RSSI samples used. RssiSmoothing selects the number of RSSI samples from a minimum of 2
samples up to 256 samples in increments of power of 2. Table 37 gives the estimation of the RSSI accuracy for a 10 dB
SNR and response time versus the number of RSSI samples programmed in RssiSmoothing.
Page 86
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