Radio broadcasts for public transmission are generally transmitted using which modulation technique?
Electronics and Communication Engineering
Communication Systems
Difficulty: Easy
Choose an option
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Aamplitude modulation
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Bfrequency modulation
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Cboth amplitude and frequency modulation
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Dneither amplitude nor frequency modulation
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Epulse code modulation
Answer
Correct Answer: amplitude modulation
Explanation
Introduction / Context:Radio broadcasting historically used AM and later FM depending on frequency bands. This question asks about the general method used for traditional long-distance radio broadcasting.
Given Data / Assumptions:
- Broadcast band: Medium wave (MW) and shortwave (SW) radio.
- Standard practice worldwide until the dominance of FM for high fidelity.
Concept / Approach:Amplitude modulation (AM) was used widely because it is simple to implement and robust over long distances. Frequency modulation (FM) is used for VHF high-fidelity audio but not considered “general broadcast” historically.
Step-by-Step Solution:
Radio broadcasts in MW/SW = AM.FM = higher quality, short range (VHF ~88–108 MHz).Hence the default broadcast type = AM.Verification / Alternative check:ITU and broadcasting standards confirm AM is the general technique for global reach.
Why Other Options Are Wrong:
FM: not used generally worldwide, only in specific bands.Both: no, systems are distinct.PCM: digital telephony, not classical broadcast.Common Pitfalls:
Mixing local FM stations with global definition of “radio broadcast.”Final Answer:
amplitude modulation