1
GATE ECE 2007
+2
-0.6
The raised cosine pulse p(t) is used for zero ISI in digital communications. The expression for p(t) with unity roll-off factor is given by $$p(t) = {{\sin \,4\,\pi \,W\,t} \over \matrix{ 4\,\pi \,W\,t(1 - 16{W^2}{t^2}) \hfill \cr \hfill \cr \hfill \cr} }$$\$ The value of p(t) at $$t = {1 \over {4\,W}}$$ is
A
- 0.5
B
0
C
0.5
D
$$\infty$$
2
GATE ECE 2007
+2
-0.6
In a Direct sequence CDMA system the chip rate is $$1.2288\,\, \times \,\,{10^6}$$ chips per second. If the processing gain is desired to be at least 100. The data rate
A
must be less than or equal to $$12.288\,\, \times \,\,{10^3}$$ bits per sec.
B
must be greater than $$12.288\,\, \times \,\,{10^3}$$ bits per sec.
C
must be exactly equal to $$12.288\,\, \times \,\,{10^3}$$ bits per sec.
D
can take any value less than $$12.288\,\, \times \,\,{10^3}$$ bits per sec.
3
GATE ECE 2006
+2
-0.6
The minimum step-size required for a Delta-Modulator operating at 32 K samples/sec to track the signal (here u(t) is the unit-step function)

x(t) = 125t(u(t) - u (t - 1) + (250 - 125t) (u (t - 1) - u (t - 2 )) so that slope - overload is avoided, would be

A
$${2^{ - 10}}$$
B
$${2^{ - 8}}$$
C
$${2^{ - 6}}$$
D
$${2^{ - 4}}$$
4
GATE ECE 2004
+2
-0.6
Three analog signals, having bandwidths 1200 Hz, 600 Hz and 600 Hz are sampled at their respective Nyquist rates, enocodes with 12 bit words, and time division multiplexed. The bit rate for the multiplexed signal is
A
115.2 kbps
B
28.8 kbps
C
57.6 kbps
D
38.4 kbps
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