This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Envelope Detector”.
1. Envelope Detector is a/an ________
a) Coherent detector
b) Asynchronous Detector
c) Synchronous Detector
d) Product Demodulator
Explanation: Envelope detectors are asynchronous in nature. The advantage of asynchronous over synchronous is that it is simple, cheap, setup is faster.
2. Effective radiated power (ERP) is equal to ________
Explanation: Effective radiated power is equal to the product of antenna gain (Gt) and power transmitted (Pt).
Explanation: Power of a transmitter that is radiated from an isotropic antenna will have a uniform power density in all direction. The power density at any distance ‘R’ for an isotropic antenna is equal to .
4. Compact discs mainly use ________
a) optical recording
b) magnetic recording
c) magnetic retrieval
d) both optical and magnetic recording
Explanation: Compact disk (CD) is mainly used for storage of data. It was developed only for store and play only audio but was later adapted for storage of data also. It mainly used optical recording and retrieval.
5. If the distance between antenna and source doubles, the received signal power decreases by 1⁄4.
6. Power density follows inverse square law.
Explanation: With increase in distance power density decreases. So, we can also say that power density is inversely related to distance.
7. There is no requirement of IF amplifier stages for a video monitor.
Explanation: Video amplifier is used to amplify video signals before passing them to a Cathode ray tube. And there is no need of IF amplifier stages for a video monitor.
8. Helical antenna is circularly polarized.
Explanation: In helical antenna, polarization is equally divided between vertical and horizontal components and thus it is circularly polarized.
9. The intermediate frequency of a superheterodyne receiver is 500KHz. What is the image frequency at 1200KHz?
Explanation: Image frequency is equal to (1200 – 500) which is equal to 700KHz.
10. Which of these amplifiers is used for impedance matching?
a) Common Base
b) Common Emitter
c) Common Collector
d) Any one of above
Explanation: Output impedance of common collector is low and thus it is suitable for impedance matching.
Sanfoundry Global Education & Learning Series – Analog Communications.
To practice all areas of Analog Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.