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RF Transmitters and Receivers?

Discussion in 'Radio and Wireless' started by jeff77789, Mar 21, 2013.

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  1. jeff77789

    jeff77789

    17
    0
    Feb 23, 2013
    I've been trying to use this pair of RF transmitter/receiver:

    https://www.sparkfun.com/products/10534
    https://www.sparkfun.com/products/10532


    does anybody have any experience with what type of signal it actually sends/receives?

    you see that in the datasheet for the receiver you have a digital output and a linear output as well.

    I sent a pwm type output through this and it looks like it kind of successfully transfers but the signal is very noisy, disrupting the pwm signal. i dont think an analog voltage signal would transfer

    thanks
     
  2. davenn

    davenn Moderator

    13,833
    1,950
    Sep 5, 2009
    they use amplitude shift keying

    see here


    cheers
    Dave
     
  3. jeff77789

    jeff77789

    17
    0
    Feb 23, 2013
    okay so i finally figured out to find a digital signal to send through these. there is another problem that comes up:

    1. the signal being sent to the transmitter is 9600 baud which is 2x the 4800baud for the tx/rx (which i do not know if it affects the signal any)

    2. when i view the signal, it is very noisy and it looks like it is just random numbers. the thing is, if i turn off the Tx, the values stay in their random state and it looks like there is no uniformity
     
  4. brevor

    brevor

    87
    16
    Apr 9, 2013
    1. Sorry, you can't send 9600 baud data through a TX/RX that only supports up to 4800 baud.

    2. Im not sure what you mean by this. Please explain a bit more.
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,496
    2,837
    Jan 21, 2010
    Yeah, I'd certainly be trying to get it to work at 4800 baud before pushing it beyond its specs.

    It *may* work at 9600 baud, but it may do so only with a very high signal, low noise, etc. Or it might not work at all.
     
  6. jeff77789

    jeff77789

    17
    0
    Feb 23, 2013
    Now I am at the point where i can send a digital signal at 4800 baud through these sensors.

    The thing is, If it send "123" on the other side, i rarely ever get the "495051" sequence (refer to ASCII table)

    the accuracy rate is less than 10% and I have no Idea why the signal is so "noisy"

    is there any way i can improve on this?
     
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