 |  Modulation Techniques 42 Flashcards |  Start |
 | What is Amplitude Modulation (AM)? |  Card: 1 / 42 |
| AM varies the carrier signal's amplitude in proportion to the modulating signal. | Card: 2 / 42 |
| True or False: The maximum efficiency of AM occurs at a modulation index of 1. | Card: 3 / 42 |
| True. Maximum efficiency is 33.33% at m = 1. | Card: 4 / 42 |
| Fill in the blank: The bandwidth of AM is _____ times the frequency of the modulating signal. | Card: 5 / 42 |
| 2 | Card: 6 / 42 |
| How is the modulation index (m) defined in AM? | Card: 7 / 42 |
| M = A_m / A_c, where A_m is the modulating signal's amplitude. | Card: 8 / 42 |
| What happens when the modulation index (m) exceeds 1? | Card: 9 / 42 |
| Overmodulation occurs, causing distortion. | Card: 10 / 42 |
| What is Carson's Rule for FM bandwidth? | Card: 11 / 42 |
| BW_{FM} = 2(Δf + f_m) where Δf is frequency deviation. | Card: 12 / 42 |
| Which modulation scheme provides better noise immunity, AM or FM? | Card: 13 / 42 |
| FM provides better noise immunity than AM. | Card: 14 / 42 |
| What is the relationship between FM and PM? | Card: 15 / 42 |
| PM is equivalent to FM with a differentiated modulating signal. | Card: 16 / 42 |
| What is the spectral efficiency formula? | Card: 17 / 42 |
| Η = R_b / BW, where R_b is bit rate and BW is bandwidth. | Card: 18 / 42 |
| Multiple Choice: What is the bandwidth for QPSK? A) R_b B) R_b/2 C) 2R_b D) 2R_b/3 | Card: 19 / 42 |
| B) R_b/2 | Card: 20 / 42 |
| What is pulse code modulation (PCM)? | Card: 21 / 42 |
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| PCM represents an analog signal through sampling, quantization, and encoding. | Card: 22 / 42 |
| What does the signal-to-quantization-noise ratio (SQNR) indicate? | Card: 23 / 42 |
| SQNR measures the quality of a quantized signal. | Card: 24 / 42 |
| What occurs during overmodulation in AM? | Card: 25 / 42 |
| It causes distortion in the transmitted signal. | Card: 26 / 42 |
| Why is frequency modulation preferred for high-fidelity audio? | Card: 27 / 42 |
| FM offers better signal quality and noise resistance. | Card: 28 / 42 |
| What is the formula for total transmitted power in AM? | Card: 29 / 42 |
| P_t = P_c(1 + m²/2) | Card: 30 / 42 |
| What is the bit rate for 16-QAM if the symbol rate is 10 MHz? | Card: 31 / 42 |
| Bit rate is R_b = 4 × 10 MHz = 40 Mbps. | Card: 32 / 42 |
| True or False: In 64-QAM, each symbol represents 6 bits. | Card: 33 / 42 |
| True. 64-QAM uses 2^6 = 64 symbols. | Card: 34 / 42 |
| What does the modulation index in FM represent? | Card: 35 / 42 |
| It represents the ratio of frequency deviation to modulating frequency. | Card: 36 / 42 |
| What is the peak envelope voltage in AM? | Card: 37 / 42 |
| V_peak = A_c(1 + m) | Card: 38 / 42 |
| Multiple Choice: What is the efficiency formula in AM? A) η = m² / (2 + m²) B) η = m / 2 C) η = m / (1 + m) D) η = 1 / m | Card: 39 / 42 |
| A) η = m² / (2 + m²) | Card: 40 / 42 |
| What effect does increasing the modulation index have on AM signal bandwidth? | Card: 41 / 42 |
| It increases the bandwidth needed for transmission. | Card: 42 / 42 |
| Completed! Keep practicing to master all of them. |  Restart |
