jgorman01 wrote: > I may be wrong but I beleive your theory doesn't assume that the RF > energy at your reciever's antenna is not additive. In other words, > the signal from the transmitter you want to hear and the interfering > signal do not add together.
Do you mean that superposition theorem does not apply? You are wrong, Jim. > You can only discern the strongest signal. In psychoacoustics, that's called "masking", if both signals are close, but on different frequencies. > An example is, that if you put a carrier on the air and I > receive it at S9 and then someone else puts a carrier on the exact > same frequency but it only arrives at S8, I'll never know it is > there. It is not the case. Two coherent signals, one 6 dB weaker than the other, when added up give rise to a signal 0.972 dB stronger than the stronger one. You may not perceive it, but it does not deny the superposition theorem. I doubt they can add up coherently from two separate VFO's (unless you have two GPS locked DDS's) ...you would get a very low frequency beat, and if it is below 20 Hz (or your audio's low frequency cutoff), you will see the S meter dancing, and hear nothing at all. I used to calibrate my crystal calibrators that way. > Therefore, when you remove the interfering signal, you also remove > any possibility of retreiving information from the signal you want to > hear. ??? > Consequently, you will never have a coherent signal to decode. > It will always have missing information. What information does an umodulated carrier carry ? > Any other assumption means noise, especially random noise, would not > be a problem, and that you could always subtract a signal from it. > Every mode I know of, digital or analog, has a minimum signal to > noise ratio that is required to decode it. Analog signals do not need to be decoded, are they just perceived. Maybe you can specify a certain minimum SNR for comfort, that's all. > Jim WA0LYK __________________________________________ XIII Convención Científica de Ingeniería y Arquitectura 28/noviembre al 1/diciembre de 2006 Cujae, Ciudad de la Habana, Cuba http://www.cujae.edu.cu/eventos/convencion Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
