[Lowfer] WPM to QRSS to SYM/SEC to Baud Rate - Calculations ??

[David L. Wilson]

As QRSS is cw, that should be the number of times one could send "PARIS " (taken as the average Morse code word length) in a minute(note the blank after the last letter to separate it from the next transmission of the word.
Let us see if we can get the formula WPM=1.2/dot length  (it does not matter if it is QRSS or regular Morse code).
"PARIS " is
".--. .- .-. .. ...   " so the number of dot (dit) lengths needed (with the standard 3  dot lengths for a dash (dah), 1 dot length between character parts, 3 dot lengths between characters, and 7 dots lengths between words) is 
.--.	1+1+3+1+3+1+1=11 dot lengths                                  
Space between letters	3 dot lengths                                  
.-	1+1+3=5 dot lengths                                  
Space between letters 3 dot lengths                                  
.-.	1+1+3+1+1=7 dot lengths                                  
Space between letters	3 dot lengths                                  
..	1+1+1=3 dot lengths                                  
Space between letters	3 dot lengths                                  
...	1+1+1+1+1=5 dot lengths                                  
Space between words=7 dot lengths
giving  a total of 50 dot lengths to transmit "PARIS "
This means that if a dot is D seconds long, that "PARIS " takes 50*D seconds or 50D sec/(60 sec/min)=(5/6)D minutes, so that 1/((5/6)D)=(6/5)/D=1.2/D transmissions of "PARIS " occur in a minute. which is the desired formula.

But this formula is only meaningful for Morse code.  Given baudrate as in the other question, one can get formulas relating the baudrate to WPM for codes where the number of bits per character is constant--like Baudot is easy:  the standard word "PARIS " is 6 characters (including the blank); so if a character takes n bits, that requires 6n bits; at a baudrate of b bits per second, the word will require 6n/b seconds or(6n/b)/60 min=0.1n/b min, giving 10(b/n) words per second.  Thus a 7 bits code like Baudot with 1 start, 5 character, and 1.5 stop bits for n=7.5 bits total per character, 50 Bd will be 10(50/7.5)=66 2/3 WPM; similarly 75 Bd will be 100 WPM. 

I do not know the particulars of Hellschrieber to attempt a similar calculation, but I would caution that the word "PARIS " might not be typical.  Its length in sending in time is considered average for Morse, its length is considered typical for Baudot and ASCII which have fixed number of bits per character.  But for codes not meeting such conditions, "PARIS " may not be representative.
--
David L. Wilson
dwilson314 at verizon.net


> -----Original Message-----
> From: k2ors at verizon.net [mailto:k2ors at verizon.net]
> Sent: Wednesday, January 26, 2011 7:41 PM
> To: dwilson314 at verizon.net
> Cc: lowfer at mailman.qth.net
> Subject: Re: Re: [Lowfer] WPM to QRSS to SYM/SEC to Baud Rate -
> Calculations ??
> 
> Andy,
> 
>     The usual formula is WPM = 1.2/QRSS dot length seconds so for  QRSS60
> 1.2/60 = 0.02WPM
> 
> 73 Warren K2ORS
>           WD2XGJ
>           WD2XSH/23
>           WE2XEB/2
>           WE2XGR/1