This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Synchronous TDM”.
1. As the length of a long-wire antenna is increased ________
a) the number of lobes also increase
b) the number of lobes decrease
c) efficiency increase
d) the number of nodes decrease
Explanation: An antenna is basically a transducer that converts radio frequency fields into alternating current or vice versa. They can be used for both transmission and reception of radio signals. If the length of a long wire antenna is increased then the number of lobes also increases.
2. A non-resonant antenna will________
a) not transmit
b) not receive
c) cause SWR on the feed cable
d) transmit and receive the signal at the same time
Explanation: A non-resonant antenna have wider bandwidth as compared to resonant antenna. It also has less sensitivity than resonant antenna. A non-resonant antenna will cause SWR on the feed cable.
3. The typical antenna in an AM radio is a ________
b) folded dipole
c) ferrite “loop-stick”
d) loop dipole
Explanation: The ferrite rod antenna is a form of RF design that is universally used in portable transistors broadcast receivers. It is also being used increasingly in wireless applications in areas such as RFID. It is a type of typical antenna in an AM radio.
4. A 1-MHz monopole antenna must be ________
a) mounted vertically
b) mounted horizontally
c) atleast one half wavelength long
d) atleast one wavelength long
Explanation: A monopole antenna consists of a straight rod shaped conductor. It is often mounted perpendicularly over some type of conductive surface, called a ground plane.
5. “Ground Effects” in antenna effects ________
a) antenna’s radiation
b) antenna’s reception capacity of signals
c) antenna’s SWR
d) antenna’s power
Explanation: Ground generally reflects the wave back that comes to it. It also affects antenna by effecting the radiation.
6. An antenna’s beamwidth is measured ________
a) from +90° to -90°
b) between half power points
c) between the minor side lobes
d) from front to back
Explanation: The angle between the half power points of the main lobe with respect to the peak effective radiated power is called half power beamwidth. It is generally measured between half power points.
7. What is the front to back ratio of a half wave dipole antenna?
a) 0 dB
b) 10 dB
c) 100 dB
Explanation: The front to back ratio mean the ratio of power gain between the front and back of a directional antenna. For a half-wave dipole antenna its value comes out to be 0dB.
8. AM waves is represented by Et cos ωc t. What does Et denotes?
b) carrier signal
c) modulating signal
Explanation: AM wave is represented by (A+xt) cos ωc t or Et cos ωc t, where xt is modulating signal, A is amplitude and Et is amplitude of AM wave.
9. The radiation of energy from an antenna can be seen in the ________
a) standing wave around antenna
b) radiation resistance of the antenna
c) reflected resistance of the antenna
d) I2R loss of the antenna
Explanation: An antenna is basically a transducer that converts radio frequency fields into alternating current or vice versa. They can be used for both transmission and reception of radio signals. Radiation resistance of the antenna is just a measure of radiation of energy from antenna.
10. The end-to-end length of a half wave dipole antenna is actually ________
a) slightly shorter than a half wavelength
b) slightly longer than a half wavelength
c) one half wavelength
d) one wavelength
Explanation: The half way dipole antenna is also known as Hertz antenna. It consists of two straight collinear conductors of equal length separated by a small feeding gap. The length of half wave dipole antenna is slightly shorter than half wavelength.
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.