GATE ECE 2007 | Digital Communication Systems Question 27 | 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

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

115.2 kbps

28.8 kbps

57.6 kbps

38.4 kbps

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 25 English 1

GATE ECE 2004 Communications - Digital Communication Systems Question 25 English 1

GATE ECE 2004 Communications - Digital Communication Systems Question 25 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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