Re: Multivariate permutations?


"NickC" <n_campregher@xxxxxxxxxxxxxxx> wrote in message
news:698ad1dpmk17l999sjlgqnshmc0dphngg5@xxxxxxxxxx
> Hi everyone,
>
> I am having a bit of a problem figuring something out, and I was
> hoping I could get some help. I am an electronic engineer, so I have a
> little bit of maths background.
>
> Here is the problem:
>
> I have a set of signals to be mapped onto a set of transmission lines.
> I know how many transmission lines there are (n) and how many signals
> I need to map (k). Furthermore, I know that (p) transmission lines are
> faulty and should not be used to map the signals.
>
> Assuming a completely random process for both signal mapping and fault
> occurrence, how do I find the probability that all my signals will be
> mapped onto working transmission lines?
>
> I hope the problem is clear. I can do this by hand for a small n,k,p,
> and I have been trying to figure out a general formula, but no success
> so far!

The prob of a signal taken at random getting a faulty line is p/n. The
subsequent selections get faulty line probabilities which are just the same,
ie they are idependent of each other.
The prob. of each signal getting a good line is 1 - p/n
The prob of k signals getting a good line is (1-p/n)^k

Is it this easy? Or is this wrong.

rusty


.

Relevant Pages

  • Re: Echos from the past, code test not a hindrance to a ticket
    ... There is too much noise and signals are subject to the vagaries of wave propagation phenomena. ... I'd have to work it out, but I think there are some ham segments where we'd need more bandwidth than is alloted ... High Command that determines who gets what frequencies for what path at what time. ... For example, a system of 128 states could be done, if the system S/N is good enough, allowing the transmission of seven units of information per unit time in the same bandwidth as was previously used for one unit. ...
    (rec.radio.amateur.policy)
  • Re: Phyllis was this approved by Dr Jones Lawyers? If not SHUT THE FUCK UP
    ... > Telemedicine involves a high speed hookup so the patient can be "seen" ... > individual patients and the transmission of information related to ... > Asynchronous communication: ... > of signals in a frequency-modulated fashion, ...
    (sci.med.diseases.lyme)
  • Re: what video (and audio) format for distribution?
    ... transmission system to be broadcast to the viewers at home would all be ... would see exactly the same signals the broadcasters saw. ... Use of some of the newer techniques for compression make ...
    (sci.engr.television.broadcast)
  • Re: Double dipole better than YAGI 5 elements??
    ... Double antennas deliver double the signal ... The wireless shadows of tall buildings are a challenge for transmission. ... radio signals bounce off objects in the ... as 'transmit diversity', ...
    (rec.radio.amateur.antenna)
  • Re: Double dipole better than YAGI 5 elements??
    ... Double antennas deliver double the signal ... The wireless shadows of tall buildings are a challenge for transmission. ... radio signals bounce off objects in the ... as 'transmit diversity', ...
    (rec.radio.amateur.antenna)