Averaging AtoD samples

[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)

[HankMcSpank]

ok, so scalerobotic's link to Melanie's 'sorting numbers' article, is exactly what I need, so I'm trying to get the thing to work.

i've basically got a small array that a prepopulate with some random numbers.

@ __CONFIG _FCMEN_OFF & _HS_OSC & _WDT_OFF & _MCLRE_OFF & _CP_OFF & _IESO_OFF & _BOR_OFF & _PWRTE_OFF

DEFINE  OSC 20          ' set Oscillator at 20Mhz.
DEFINE  NO_CLRWDT 1   ' PBP doesn't clear WDT automatically
DEFINE HSER_CLROERR 1
DEFINE HSER_TXSTA 24h ' Enable transmit
DEFINE HSER_SPBRG 129 ' set USART to 9600 baud  @20Mhz

    CounterA var Byte
    DataA var Byte
    RawData var Byte [6]
    Averaged var byte
    hserout [27,91,72]          'home cursor
    hserout [27,91,50,74]       'clear screen
    
    RawData[0]  = 25
    RawData[1]  = 27
    RawData[2]  = 32
    RawData[3]  = 30
    RawData[4]  = 34
    RawData[5]  = 33

    
    hserout ["before....", 13, 10]
    hserout [dec rawdata[0],13,10]
    hserout [dec rawdata[1],13,10]
    hserout [dec rawdata[2],13,10]
    hserout [dec rawdata[3],13,10]
    hserout [dec rawdata[4],13,10]
    hserout [dec rawdata[5],13,10]
    hserout [13,10]
    hserout [13,10]


    CounterA =0
    gosub SortArray
    gosub Average_data
    hserout ["after....", 13, 10]
    hserout [dec rawdata[0],13,10]
    hserout [dec rawdata[1],13,10]
    hserout [dec rawdata[2],13,10]
    hserout [dec rawdata[3],13,10]
    hserout [dec rawdata[4],13,10]
    hserout [dec rawdata[5],13,10]

    hserout ["averaged = ", dec averaged,13,10]
    goto end1
    
    
Average_data:
    hserout [dec rawData[2]," + ", dec rawData[3], 13,10]
    Averaged = (rawData[2]+rawData[3])/2    ' average the middle two of 6 ongoing samples
    return

SortArray:
SortLoop:
    If RawData(CounterA+1) < RawData(CounterA) then
        DataA=RawData(CounterA)
        RawData(CounterA)=RawData(CounterA+1)
        RawData(CounterA+1+0)=DataA
        If CounterA > 0 then CounterA=CounterA-2
        endif
    CounterA=CounterA+1
    If CounterA < 5 then goto SortLoop
    Return

    end1:
    end

here's my screen output (I average the middle two numbers Rawdata[2] & RawData[3] )....

before....
25
27
32
30
34
33

after....
6
25
27
30
32
33
averaged = 31

It all works (ie sorts & averages correctly) - but where on earth has the number 6 in the sorted numbers come from? (there was no number six in the original array - also, whatever number I place in that array position RawData[4] comes out sorted as 6!?!!)

Edit: Ok, think I've stumbled on the issue - it seems to be related to my array declaration ....because when I use RawData var Byte [8] ...everything works.

So why can't I declare an array 5 bytes 'deep'? ie RawData var byte [5] ???

[aratti]

It all works (ie sorts & averages correctly) - but where on earth has the number 6 in the sorted numbers come from?

Check out the sorting routine because it doesn't work. The first number should be 25, while the last number should be 34 not 33.

Also your average is not correct, since 27 + 30 / 2 = 28.5 (28 as integer) not 31

Very likely the error comes from the wrong sorting.

Cheers

Al.

[Ioannis]

I suppose that you corrected the array definition from[6] to [5].

And then the check in the program:

If CounterA < 5 then goto SortLoop

to this:

If CounterA < 4 then goto SortLoop

Ioannis

[HankMcSpank]

Guy - what can I say .....I initially used random 1-6 for my numbers in the array & it sorted them & averaged them fine! (ie 1,2,3,4,5,6 was the screen output!)

I'm puzzled why my screen output posted above doesn't look like it's working (for either the sorting or the averaging!! lol) - it was late ...that's my lame excuse for not picking up on that! The 'sorting' part of the code was a direct lift from Melanie's article.

I'm at work now (don't tell my boss!) , so will revisit this tonight.