Time between update beacon varies. Filtering needs samples that are seperated by same time?

[kevindekemele]

Hello,

When receiving beacons which have for instance, advertising period of 200ms; it seems that the beacon updates are received on random anywhere between 50ms up to 3000ms.

Here is my startScan() that shows this:

		evothings.eddystone.startScan(
			function(beacon)
			{
					if(beacon.address in beacons){
						var timediff = Date.now() - beacon.timeStamp;
						console.log(beacon.address + "updated with 
"+ beacon.rssi + " at " + timediff);
					}
					else{
						console.log(beacon.address + "discovered with "+ beacon.rssi + " at " + Date.now());
	
					}
					// Insert/update beacon table entry.
					beacon.timeStamp = Date.now();
					beacons[beacon.address] = beacon;			
				
			},
			function(error)
			{
				console.log('Eddystone Scan error: ' + JSON.stringify(error));
			});

I want to filter the erratic RSSI signal. I have a background in signal processing, and these discrete type signals can only be filtered if each update has the same time between them (uniform vs non-uniformally sampled signals).

So your lowPass filter doesn't really make much sense? You can not talk about a cutoff frequency if the time between each sample varies enormously.

Or do I have to assume that each update does correspond with 200 ms time difference (or is not every advertisement received??)