MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Analog Communications knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Consider a discrete-time channel |
| A. | 10-7 |
| B. | 10-6 |
| C. | 10-4 |
| D. | 10-2 |
| Answer» D. 10-2 | |
| 2. |
Consider a communication scheme where the binary-valued signal X satisfies { |
| A. | strictly positive |
| B. | zero |
| C. | strictly negative |
| D. | strictly positive, zero, or strictly negative depending on the nonzero value of 𝜎2 |
| Answer» D. strictly positive, zero, or strictly negative depending on the nonzero value of 𝜎2 | |
| 3. |
Identify the modulation schemes for the shown signal constellation diagram: |
| A. | ASK |
| B. | MSK |
| C. | FSK |
| D. | QAM |
| Answer» E. | |
| 4. |
An analog pulse s(t) is transmitted over an additive white Gaussian noise (AWGN) channel. The received signal is r(t) = s(t) + n(t), where n(t) is additive white Gaussian noise with power spectral density \(\frac{{{{\rm{N}}_0}}}{2}\). The received signal is passed through a filter with impulse response h(t). Let |
| A. | \({{\rm{E}}_{\rm{s}}} = {{\rm{E}}_{\rm{h}}};{\rm{SN}}{{\rm{R}}_{{\rm{max}}}}{\rm{\;}} = \frac{{2{{\rm{E}}_{\rm{s}}}}}{{{{\rm{N}}_0}}}\) |
| B. | \({{\rm{E}}_{\rm{s}}} = {{\rm{E}}_{\rm{h}}};{\rm{SN}}{{\rm{R}}_{{\rm{max}}}}{\rm{\;}} = \frac{{2{{\rm{E}}_{\rm{s}}}}}{{2{{\rm{N}}_0}}}\) |
| C. | \({{\rm{E}}_{\rm{s}}} > {{\rm{E}}_{\rm{h}}};{\rm{SN}}{{\rm{R}}_{{\rm{max}}}}{\rm{\;}} = \frac{{2{{\rm{E}}_{\rm{s}}}}}{{{{\rm{N}}_0}}}\) |
| D. | \({{\rm{E}}_{\rm{s}}} = {{\rm{E}}_{\rm{h}}};{\rm{SN}}{{\rm{R}}_{{\rm{max}}}}{\rm{\;}} = \frac{{2{{\rm{E}}_{\rm{h}}}}}{{{{\rm{2N}}_0}}}\) |
| Answer» B. \({{\rm{E}}_{\rm{s}}} = {{\rm{E}}_{\rm{h}}};{\rm{SN}}{{\rm{R}}_{{\rm{max}}}}{\rm{\;}} = \frac{{2{{\rm{E}}_{\rm{s}}}}}{{2{{\rm{N}}_0}}}\) | |
| 5. |
If Eb, the energy per bit of a binary digital signal, is 10-5 Ws (Watt-Second) and the one-sided power spectral density of the white noise, N0 = 10-6 W/Hz, then the output SNR of the matched filter is |
| A. | 26 dB |
| B. | 10 dB |
| C. | 20 dB |
| D. | 13 dB |
| Answer» C. 20 dB | |
| 6. |
A binary symmetric channel with p as transition probability, users repetition code ‘n’ times, with n = 2m + 1 being an odd integer. In a block of n bits, if the number of zeros exceed number of decoder decodes it as ‘0” otherwise as “ 1”. An error occurs when m + 1 or more transmissions out 3 are incorrect. What is the probability of error? |
| A. | 3p2 (1 –p) +p3 |
| B. | 5p2 (1 –p) +(1/3)p3 |
| C. | 2p (1 –p) +p2 |
| D. | p3 (1 –p) +p2 |
| Answer» B. 5p2 (1 –p) +(1/3)p3 | |
| 7. |
If an m-derived filter section is built with m = 1, it will _______ |
| A. | not be physically realizable |
| B. | not act as filter |
| C. | become a prototype section |
| D. | be used only where very high attenuation near cutoff is desired |
| Answer» D. be used only where very high attenuation near cutoff is desired | |
| 8. |
Modulation technique used in low speed modem is ______. |
| A. | FSK |
| B. | DPSK |
| C. | PWM |
| D. | PCM |
| Answer» B. DPSK | |
| 9. |
Let \(s\left( t \right) = rect\left( {\frac{{t - 3}}{3}} \right)\) be a signal passed through an AWGN (additive white Gaussian noise) channel with noise power spectral density (PSD) \(\frac{{{N_0}}}{2}\) to get v(t). If v(t) is passed through a matched-filter that is matched to s(t), then output signal-to noise ratio (SNR) of the matched-filter is |
| A. | \(\frac{6}{{{N_0}}}\) |
| B. | \(\frac{2}{{{N_0}}}\) |
| C. | \(\frac{3}{{{N_0}}}\) |
| D. | \(\frac{4}{{{N_0}}}\) |
| Answer» B. \(\frac{2}{{{N_0}}}\) | |
| 10. |
A two-step procedure in a typical diffusion apparatus to obtain the complementary-error function Gaussian distribution involves the first step and second step respectively as |
| A. | Predeposition and Drive-in |
| B. | Predeposition and Drive-out |
| C. | Drive-in and Postdeposition |
| D. | Drive-out and Postdeposition |
| Answer» B. Predeposition and Drive-out | |
| 11. |
Why CSMA/CD network has a minimum length for packets? |
| A. | to increase the data rate |
| B. | to decrease the data rate |
| C. | to prevent packets from reaching all other nodes |
| D. | to make sure that all other nodes hear a collision in progress |
| Answer» E. | |
| 12. |
A frequency synthesizer is _________ |
| A. | A VCO phase locked to a reference frequency |
| B. | A VFO phase locked to a reference frequency |
| C. | A fixed RF generator |
| D. | A variable RF generator |
| Answer» B. A VFO phase locked to a reference frequency | |