This is a histogram of key down period (i.e., either dots or dashes). It seems that the dot to dash ratio is around 25:100, or 1:4.
This is a histogram of key up period, or of spaces.
Save Time: 2014-02-02 15:12:44
Units:(mV)
CH1
Frequency: 4.564 Hz
Period: 219.091 mS
PK-PK: 3.520 V
1 400.00
2 0.00
3 0.00
4 0.00
5 80.00
6 0.00
7 0.00
8 -80.00
9 0.00
10 0.00
11 -80.00
12 0.00
13 0.00
14 0.00
15 0.00
16 160.00
17 0.00
18 0.00
19 80.00
20 1760.00
21 2880.00
22 3280.00
23 3280.00
24 3280.00
The text file obtained from the oscilloscope is something like this.
BEGIN { th=2000; n=10; b4=1 }
/^[0-9]/ {
if($2>th) out=1
else
out=0
if(b4==1 && out==0)
i=n
if(i>0) {
out=0
i--
}
b4=out
print out
}
This awk programs gives a “0” and “1” sequence by slicing the voltage.
BEGIN { b4=1; ndown=0; nup=0 }
{
if(b4==1 && $1==0) {
ndown=0
if(nup>0) print "up", nup
}
if(b4==0 && $1==1) {
nup=0
if(ndown>0) print "dw", ndown
}
if($1==0)
ndown++
else
nup++
b4=$1
}
And this program counts the run of either “0”s or “1”s, and gives:
dw 20 up 34 dw 105 up 98 dw 96 up 44 dw 22 up 26 dw 24 up 28 dw 21 up 31 dw 11 up 156