signal output of an antenna
Hi Rick
So far, I poke the rssi signal according to your advice:
- if the distance is far enough, the rssi shows a good variation according to the modulation signal.
- when I reduce the distance, this variation becomes smaller but is still in phase. the rssi signal grows up to the max
- there is a point when variation is too small for the data slicer. rssi is at max.
- after that, the rssi is still at max, but a (very small) variation reappears with opposite phase. There are no ringing or spikes.
I'm sorry that I don't have screen snapshot (i will do it later when I come back to work)
I suppose that the behaviour of the rf amplifier is as the attached bitmap, so
when the transmitter sends a "0", there are enough residual rf reaching the receiver which deliver a highest rssi voltage
when the transmitter sends a "1", the receiver is so heavily overloaded (working far from the compression point), and delivers a slighly lower rssi.
In your opinion, is it possible that such condition can occurs?
I will try to confirm with more "scientific" equipment later.
Lang