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1.how com discrete carriers(present in ifft) modulate input sequence?
Whay call the carriers "discrete". each of them is a continuous signal, they are at discrete frequencies, if you want.
Each individual carrier is modulated (eg QPSK) by the input data sequence.
2.which parameter of carrier is...
Re: energy signal +power signal
Energy signal is one which has finite energy, so that it makes sense to talk about its energy, more than its power. Like a limited duration signal whose square will sum up to a finite number, but power is zero. A power signal is one that has finite power, like a...
FT is useful when the waveform is deterministic. (one can write an equation or give the value of the wave at any point in time). In PSK, FSK etc, the waveform is not predictable, since the modulating binary data is random. So we need to use PSD to find the spectrum info of such a signal. (FT of...
one half-way solution:
you would notice that
1/3 = 1/4 +1/16 + 1/64 + 1/256 + .. (to infinity)
So you could get an approx result by doing shift-by-2 many times and adding up.
- b
...and further refine by dividing the difference of above result*3 from original number by3 (using a look up...
What are the number of input possibilities? What are the output possibilities? If I assume that input possibilities are 3 (say -1, 0, +1), and out put possibilities are 2 (-1, +1), then your transition matrix can be interpreted
p(-1/-1) p(0/-1) p(-1/+1)
p(+1/-1) p(0/-1) p(-1/+1)
note: p...
What is missing above is how many levels is the PAM scheme using and number of constellation pints in the QAM. Both QAM and PAM can occupy same BW depending on the pulse shape used for modulation.
-b
eqn holds, if you convert left side to simple ratio from dBm. you'll have to find out whats the relevant BW, it is not mentioned in the first post. You could also assume the BW of the noise is the same as that for your signal, but it really depends on the system.
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if h is the impulse response (it is conventional to use h for impulse response), yes, it should be convolved with x(t). However, if h is in matrix form (corresponding to multiple paths), it could still be written as multiplication, which is the normal way of writing in wireless context.
- b
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