Averaging AtoD samples

[Darrel Taylor]

If I had a hammer ... I'd hammer in the morning ... Whaaap!
You sure you want that around you nuts?
I like pistachio's, they're cracked already.

So take the code from that page and save it to a file called "average.pbp".

Add a line in your program ...
INCLUDE "average.pbp"

When you get your reading that you want to average ... put it in the variable Value, then GOSUB Average.
The running average will be returned in the same variable (Value).

Now sit back down in your chair before you hurt yourself.
<br>

[HankMcSpank]

Hi Darrel,

Thanks!! (that all sounds too simple...even for someone as clueless as me)

I'll try that soonest ...but I'll be sure to keep the chair nearby to get right back up upon!

(PS I wasn't saying your routine was a hammer to crack a nut per se, but simply a hammer to crack a nut with my simple requirements!)

PPS why do I keep getting that Random Question "missing letter from the word cof_ee" wrong? It's an 'f' damnit.

[HankMcSpank]

This is somewhat related to my ongoing pitch detection quest (in that it's what's driven me to ask - I'm seeing occasional glitches in the input signal, which is causing a hiccup in the 'time measured between comparator interrupts, oncde in a while), but it could relate to any situation...not just pitch detection, so hence coming back to this thread.

My question relates to 'intelligent' averaging (& rejecting spurious values)

Let's say you have a series of data (counts, samples, pulses....whatever) , but within the data occurs the odd 'sample' that's way out of whack. For example.....

2, 2, 2, 3,2,2,3,2,2,2,8,2,2,2,3,3,2

What I'd like to do is average all those samples, but reject any one occurence that's way out of whack (eg if 1 sample per 16 is out of whack, ignore it). so in that example all the 2s & 3s get averaged, but the 8 is ignored....else it'll really dick the average!

Ok, if it were that simple I could probably kludge something together - BUT, lets say that the above series of data is then immediately followed on by by say...

10, 10, 11, 10, 11, 10, 10, 11, 10

therefore giving a stream of values like thus.... 2, 2, 2, 3,2,2,3,2,2,2,8,2,2,2,3,3,2,10, 10, 11, 10, 11, 10, 10, 11, 10

There clearly becomes a problem, because the first couple of 10s of the second series would appear out of whack to any 'moving' simple check that was applied to the first series.

Ideally, I'd like to put in place some form of intelligent averaging routine, where only samples that are close together (say percentage terms) are averaged, any spurious samples out of that range (say 1 in 8 samples) are rejected ..... but if a threshold is breached, then the spurious values aren't treated as spurious anymore, but as new valid data to be then averaged.

Clear as mud?

[mackrackit]

I can not think of a "fast" way of doing it but you could check the difference between each pair and if the difference is more than X toss the value...
maybe...

[HankMcSpank]

I can not think of a "fast" way of doing it but you could check the difference between each pair and if the difference is more than X toss the value...
maybe...

but in that example above, it would mean when the series 10s & 11s arrived, there'd be a problem? If comparing in pairs & throwing the second one a way (ie if it deiviates too much), then the 10s would get rejected cos they're way out of whack wrt to the previous series of 2 & 3s (or have I misunderstood your line of thinking)

[mackrackit]

The first 10 would be tossed but the second 10 would not because now the pairs are 10,10,11...

[HankMcSpank]

The first 10 would be tossed but the second 10 would not because now the pairs are 10,10,11...

Aah...ok, gotcha.

Actually my example 'data series' wasn't a good one, as the data values would actually be in the hundreds (vs units which I used), which allows percentages to be used.

So, assuming a series of data coming into a variable called 'sample'...

' compare a pair called value & value2 from the incoming 'sample'

value = sample     '

upper_window = value2+(value2*4/100) 'create a window 4% above previous sample
lower_window = value2-(value2*4/100)  'create a value 4% below previous sample

if (value>= lower_window) AND (value <= upper_window) then incoming 'sample is within 'allowable error window'?
gosub average 'goto averaging routine
endif
value2 = value1

etc

would something like the above work?#

Edit: Just seen your post/link scalerobotics - off to have reader's digestion! (& yes, I did a search but I guess my keywords weren't erhm key)