GATE ECE 2007 | Digital Communication Systems Question 29 | Communications

GATE ECE 2007

MCQ (Single Correct Answer)

-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

must be less than or equal to $$12.288\,\, \times \,\,{10^3}$$ bits per sec.

must be greater than $$12.288\,\, \times \,\,{10^3}$$ bits per sec.

must be exactly equal to $$12.288\,\, \times \,\,{10^3}$$ bits per sec.

can take any value less than $$12.288\,\, \times \,\,{10^3}$$ bits per sec.

GATE ECE 2006

MCQ (Single Correct Answer)

-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

$${2^{ - 10}}$$

$${2^{ - 8}}$$

$${2^{ - 6}}$$

$${2^{ - 4}}$$

GATE ECE 2004

MCQ (Single Correct Answer)

-0.6

Choose the correct one from among the alternatives A, B, C, D after matching an item from Group 1 with the most appropriate item in Group 2.

Group
1. FM
2. DM
3. PSK
4. PCM

Group 2
P: Slope overload
Q: $${\mu - law}$$
R: Envelope detector
S: Capture effect
T: Hilbert transform
U: Matched filter

1 - T, 2 - P, 3 - U, 4 - S

1 - S, 2 - U, 3 - P, 4 - T

1 - S, 2 - P, 3 - U, 4 - Q

1 - U, 2 - R, 3 - S, 4 - Q

GATE ECE 2004

MCQ (Single Correct Answer)

-0.6

A source produces binary data at the rate of 10 kbps. The binary symbols are represented as shown in fig. GATE ECE 2004 Communications - Digital Communication Systems Question 27 English 1

GATE ECE 2004 Communications - Digital Communication Systems Question 27 English 1

GATE ECE 2004 Communications - Digital Communication Systems Question 27 English 2

The source output is transmitted using two modulation schemes, namely Binary PSK (BPSK) and Quadrature PSK (QPSK). Let $${B_1}$$ and $${B_2}$$ be the bandwidth requirements of BPSK and QPSK respectively. Assuming that the bandwidth of the above rectangular pulses is 10 kHz, $${B_1}$$ and $${B_2}$$ are

$${B_1}$$ = 20 KHz, $${B_2}$$ = 20 KHz

$${B_1}$$ = 10 KHz, $${B_2}$$ = 20 KHz

$${B_1}$$ = 20 KHz, $${B_2}$$ = 10 KHz

$${B_1}$$ = 10 KHz, $${B_2}$$ = 10 KHz

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