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How, step by step please, can the following question be answered?

"Suppose you are designing a remote control that uses short, medium, or long pulses of infrared light to send control signals to a device. How many different control codes can you define using

a) three pulses?

b) one, two, or three pulses?"

Thank you guys so much in advance!

1 Answer

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  • Mike T
    Lv 7
    9 years ago
    Favorite Answer

    a) Knowing that each signal consists of 3 pulse, there are 3 possible values (Short, Medium, and Long) for each of the pulses. Total possibilities: 3 * 3 * 3 = 27

    b) This problem is a little more interesting because now the receiver needs to be able to tell when on signal stops and the next one starts. So what we do is for any sequence less than 3 pulses, we'll select a specific pulse to be the "stop" marker. For this, I'll choose Long.

    L

    SL

    ML

    SSS

    SSM

    SSL

    SMS

    SMM

    SML

    MSS

    MSM

    MSL

    MMS

    MMM

    MML

    15

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