Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Wireless Digital Transmission

  1. Mar 22, 2015 #1
    For some reason I can't find any satisfying answers to my questions on the internet.

    1. Are mostly all remotes, phones, wifi, etc. using wireless digital transmission? If so, why does a wifi signal get weaker when you move further away? The inverse square law shouldn't apply to a digital signal as long as it makes it to the receiver, right?

    2. Do digital transmissions only require one specific frequency rather than a range of frequencies like analog? For example, you could just send pulses at 800Mhz exactly and have your receiver set to the same frequency.

    3. Are wireless digital transmissions always encrypted in some way? If so, is there anyway to get the codes? For example, if i wanted to build a receiver (other than the TV) for my Samsung TV remote, could I? Or would Samsung keep that info secret?

    4. What is the best way to read a wireless signal? Say i wanted to know the binary signal sent from my remote when I press a specific button, how could I read out the binary digits?

    Thanks a bunch!
     
  2. jcsd
  3. Mar 23, 2015 #2

    russ_watters

    User Avatar

    Staff: Mentor

    Most remotes use IR: that's what the little lens on the end of the remote is for. The others are radio/microwave frequency. They are very different from each other.

    The signal in wifi/cell phones is weaker with distance because of the inverse square law, but the quality doesn't suffer until it gets so weak that it can't be reliably detected.
    Digital signals are modulated in ways somewhat similar to the way analog signals are:
    http://en.wikipedia.org/wiki/Direct-sequence_spread_spectrum
    Some are, some aren't. A remote's codes are not encrypted, otherwise universal remotes couldn't be made.
    Again, most remotes are infrared. You could probably record them with an infrared camera or other IR receiver. They also tend to be analog:
    http://en.wikipedia.org/wiki/Remote_control#Technique
     
  4. Mar 23, 2015 #3
     
  5. Mar 23, 2015 #4

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Wireless Digital Transmission
Loading...