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Post by sammymtech on Mar 2, 2012 8:17:11 GMT -5
hi i want to know what exactly the envelope of the signal is? for example we say that GMSK is constant envelope modulation, i want to kno why it is called so?
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Post by samamaka on Mar 4, 2012 19:41:06 GMT -5
Help me with Digital communication question:QPSK modulation and its probability of errors
In most wireless communication standards, QPSK (Quaternary Phase-Shift Keying) modulation
is employed to transmit a binary data stream, where binary 0 and 1 are assumed equiprobable.
The optimum detector for AWGN (Additive White Gaussian Noise) channel is to demodulate the
QPSK symbols in the receiver. Using a computer program, follow the steps given below to analyze
the probability of errors for QPSK modulation over the AWGN channel.
(a) Generate the two independent Gaussian random variables with zero mean and variance 2 =
N0
2 . Verify the samples follow the Gaussian distribution.
(b) Generate a binary data stream and corresponding QPSK modulated symbols, where energy
Eb is assigned to each bit. Assuming the QPSK symbols are transmitted over the AWGN
channel, plot the symbols corrupted by the noise on the signal constellation.
(c) Plot the probability of symbol errors over Eb=N0 (dB).
(d) Compare the probability of symbol errors in your simulation to the theoretical symbol error
probability of QPSK modulation.
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