1
GATE ECE 2022
Numerical
+1
-0.33

A symbol stream contains alternate QPSK and 16-QAM symbols. If symbols from this stream are transmitted at the rate of 1 mega-symbols per second, the raw (uncoded) data rate is _________ mega-bits per second (rounded off to one decimal place).

2
GATE ECE 2022
Numerical
+1
-0.33

Consider a channel over which either symbol xA or symbol xB is transmitted. Let the output of the channel Y be the input to a maximum likelihood (ML) detector at the receiver. The conditional probability density functions for y given xA and xB are :

$${f_{\left. Y \right|{x_A}}}(y) = {e^{ - (y + 1)}}u(y + 1)$$,

$${f_{\left. Y \right|{x_B}}}(y) = {e^{(y - 1)}}(1 - u(y - 1))$$,

where, u( . ) is the standard unit step function. The probability of symbol error for this system is _________ (rounded off to two decimal places).

3
GATE ECE 2017 Set 1
+1
-0.3
In a digital communication system, the overall pulse shape p(t) at the receiver before the sampler has the Fourier transform P(f). If the symbols are transmitted at the rate of 2000 symbols per second, for which of the following cases is inter symbol interference zero?
A
B
C
D
4
GATE ECE 2017 Set 1
+1
-0.3
Which one of the following statements about differential pulse code modulation (DPCM) is true?
A
The sum of message signal sample with its prediction is quantized
B
The message signal sample is directly quantized, and its prediction is not used
C
The difference of message signal sample and a random signal is quantized
D
The difference of message signal sample with its predictions is quantized
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