MCQOPTIONS
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MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Electronic Devices and Circuits knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a fast FH spread spectrum system, the information is transmitted via FSK with non coherent detection. Suppose there are N = 3 hops/bit with hard decision decoding of the signal in each hop. The channel is AWGN with power spectral density 0.5No and an SNR 20 ~13 dB (total SNR over the three hops). The probability of error for this system is |
| A. | 0.013 |
| B. | 0.0013 |
| C. | 0.049 |
| D. | 0.0049 |
| Answer» C. 0.049 | |
| 2. |
An FH binary orthogonal FSK system employs an m 15 stage liner feedback shift register that generates an ML sequence. Each state of the shift register selects one of L non over lapping frequency bands in the hopping pattern. The bit rate is 100 bits/s. The demodulator employ non coherent detection. Suppose the hop rate is increased to 2 hops/bit and the receiver uses square law combining the signal over two hops. The hopping bandwidth for this channel is? |
| A. | 3.2767 MHz |
| B. | 13.1068 MHz |
| C. | 26.2136 MHz |
| D. | 1.6384 MHz |
| Answer» C. 26.2136 MHz | |
| 3. |
An FH binary orthogonal FSK system employs an m 15 stage liner feedback shift register that generates an ML sequence. Each state of the shift register selects one of L non over lapping frequency bands in the hopping pattern. The bit rate is 100 bits/s. The demodulator employ non coherent detection. If the hop rate is one per bit, the hopping bandwidth for this channel is? |
| A. | 6.5534 MHz |
| B. | 9.4369 MHz |
| C. | 2.6943 MHz |
| D. | None of the mentioned |
| Answer» B. 9.4369 MHz | |
| 4. |
A rate 1/2 convolution code with dfrec = 10 is used to encode a data sequence occurring at a rate of 1 kbps. The modulation is binary PSK. The DS spread spectrum sequence has a chip rate of 10 MHz. The processing gain is? |
| A. | 14 dB |
| B. | 37 dB |
| C. | 58 dB |
| D. | 104 dB |
| Answer» C. 58 dB | |
| 5. |
A rate 1/2 convolution code with dfrec = 10 is used to encode a data sequence occurring at a rate of 1 kbps. The modulation is binary PSK. The DS spread spectrum sequence has a chip rate of 10 MHz.The coding gain is? |
| A. | 7 dB |
| B. | 12 dB |
| C. | 14 dB |
| D. | 24 dB |
| Answer» B. 12 dB | |
| 6. |
A pseudo-noise (PN) sequence is generated using a feedback shift register of length m = 4. The chip rate is 107 chips per second. The period of PN sequence is? |
| A. | 1.5 s |
| B. | 15 s |
| C. | 6.67 ns |
| D. | 0.67 ns |
| Answer» C. 6.67 ns | |
| 7. |
A pseudo-noise (PN) sequence is generated using a feedback shift register of length m = 4. The chip rate is 107 chips per second. The chip duration will be? |
| A. | 1 s |
| B. | 0.1 s |
| C. | 0.1 ms |
| D. | 1 ms |
| Answer» C. 0.1 ms | |
| 8. |
A pseudo-noise (PN) sequence is generated using a feedback shift register of length m = 4. The chip rate is 107 chips per second. What is the PN sequence length? |
| A. | 10 |
| B. | 12 |
| C. | 15 |
| D. | 18 |
| Answer» D. 18 | |