words per minute confusion

Discussion in 'Wireless & RF Design' started by bhuvanesh, Jun 26, 2014.

  1. bhuvanesh

    Thread Starter Member

    Aug 10, 2013
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    Transatlantic cable in 1880's can transfer 8 words per minute(approx 5bps per second)

    I have seen this in video. In general does the the word have any specific bits or the bits of the word change accordingly
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the old standard was the word "paris" how many times paris could be sent in one minuite.
     
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  3. bhuvanesh

    Thread Starter Member

    Aug 10, 2013
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    Each letter need 8 bits so word paris need 40 bits.So 8 word per minute mean 320 bits per minute(5bps per sec) ,right?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Back then Morse code would have been used for transmission.
    paris .--. .- .-. .. ... works out to about 5bps if the speed is 8 words per minute.
     
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  5. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the standard was chosen for all baud rates, even morse code. thats why 100 baud is 100 wpm in ascii, and 45 baud is 60 wpm in baudot code..
     
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  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Back in my military days when trained in Morse, one had to qualify send/receive at so many words/min, these were blocks of 5 of random characters.
    This also co-coincided with classified security encoded messages which were formatted in the same 5 char blocks.
    Max.
     
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  7. alfacliff

    Well-Known Member

    Dec 13, 2013
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    I used to listen in as they trained in morse. knowing morse due to having earned a ham liscense before going into the army helped a lot. I had a 1st class commercial liscense then too, so I got to work on transmitters I had not trained on. made life more interesting.
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I had to work occasionally to the civilian professionals, Cable & Wireless Co etc, I had to send QRS a few times as these guys were used to 35+ words a Min.
    Incidentally I was on a Radio training exercise on the edge of the Libyan Desert when the WW11 B24 Liberator, 'Lady be Good' was found after being lost during WW11 so I got to report that back to HQ.
    Max.
     
  9. bhuvanesh

    Thread Starter Member

    Aug 10, 2013
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    what that 45 baud is 60wpm in bauddot mean?
     
  10. alfacliff

    Well-Known Member

    Dec 13, 2013
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    baudot is a 5 bit code used by older teletype systems. the standard was so people could be charged for number of words sent in the old days.
     
  11. Metalmann

    Active Member

    Dec 8, 2012
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    This reminds me of my highest score in Typing class.
    52 WPM.:D

    Nowadays, I get closer to 1 word per minute.;)
     
  12. Papabravo

    Expert

    Feb 24, 2006
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    Amateur Radio Operators still use Baudot code for RTTY (Radio Teletype) communications at either 45.45 baud or 75 baud. MMTTY is a freeware package for decoding and generating RTTY as either AFSK (Audio Frequency Shift Keying) or FSK (Frequency Shift Keying). You don't even need a radio. You can record the audio output and then decode the playback. Probably wouldn't fool the NSA for long though.
     
  13. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    No it won't, most of us old Navy radio guys could tell what it was in a instant and decode just about any possible RTTY signal using gear from the stone age.

    One of my favorites, we could send 8 (encrypted) tty channels on one voice audio channel
    http://www.virhistory.com/navy/rtty-mux-ucc1.htm

    75 baud, 100wpm.
    https://www.youtube.com/watch?v=ZI2vr4jM60E
    It seemed pretty fast back then. :D
     
  14. alfacliff

    Well-Known Member

    Dec 13, 2013
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    I use digpan, has quite a few of the digital modes. the newer pc sound card programs are real easy to use, and the filtering built into the sound boards makes copy real easy with noise. by the way, they also transmit or send out the tones.
     
  15. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    They were using Morse Code, which has ABOUT 4 bits per character on the average. Dash is three times the length of a dot with "correct" morse code.
     
  16. MMcLaren

    Well-Known Member

    Feb 14, 2010
    759
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    A late reply, but hopefully informative...

    Regards, Mike

    Code ( (Unknown Language)):
    1. ;
    2. ; Some general information about Morse Code Speed;
    3. ;
    4. ; <1> A Dash is three times longer than a Dot
    5. ; <2> A Dot space is used between Dashes and Dots within a character
    6. ; <3> A pause between characters is three Dots long
    7. ; <4> A pause between words is seven dots long
    8. ;
    9. ; The word 'Paris' was established as an international standard
    10. ; for calculating the speed of Morse in words-per-minute (wpm)
    11. ; and characters-per-minute (cpm)...  This works out to 50 dots
    12. ; (or dot times) per word and yields the following timing;
    13. ;
    14. ;  5-wpm ( 25-cpm) =  60 /  250 dots = 240-msec / dot
    15. ;  6-wpm ( 30-cpm) =  60 /  300 dots = 200-msec / dot
    16. ;  7-wpm ( 35-cpm) =  60 /  350 dots = 171-msec / dot
    17. ;  8-wpm ( 40-cpm) =  60 /  400 dots = 150-msec / dot
    18. ;  9-wpm ( 45-cpm) =  60 /  450 dots = 133-msec / dot
    19. ; 10-wpm ( 50-cpm) =  60 /  500 dots = 120-msec / dot
    20. ; 15-wpm ( 75-cpm) =  60 /  750 dots =  80-msec / dot
    21. ; 20-wpm (100-cpm) =  60 / 1000 dots =  60-msec / dot
    22. ; 25-wpm (125-cpm) =  60 / 1250 dots =  48-msec / dot
    23. ; 30-wpm (150-cpm) =  60 / 1500 dots =  40-msec / dot
    24. ; 35-wpm (175-cpm) =  60 / 1750 dots =  34-msec / dot
    25. ; 40-wpm (200-cpm) =  60 / 2000 dots =  30-msec / dot
    26. ; 50-wpm (250-cpm) =  60 / 2500 dots =  24-msec / dot
    27. ;
    28.  
     
  17. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the transatlantic cables were slow due to capacitance of the cable to ground. thats hundreds of iles of wire surrounded by conductive salt water. I found a story that during development, someone decided on 10,000 volts on the wire. it worked for a day befror burning out. the did better the next time.
     
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