This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “Spectrum of Multitone Signal”.
1. Video signals are transmitted through ________
a) Frequency Modulation
b) Amplitude Modulation
c) Pulse Modulation
d) Either frequency or amplitude modulation
Explanation: Video signals required a large transmission bandwidth to transmit, So modulation of video signals is possible only by amplitude modulation.
2. What you understand by the term discone antenna?
a) combination of disc and cone
b) combination of disc and cone with a spacing of ʎ/4
c) combination of disc and cone with a spacing of ʎ/2
d) same as a simple antenna
Explanation: Discone antenna is a combination of disc and cone. It is usually vertically mounted, with disc at top and the cone beneath.
3. A system has a voltage of 15V and it produces a total current of 1300μA. Find the power of system?
Explanation: Power, P = 15 x 1300 x 10-6 =0.0195W.
4. An input resistance of 20 Kῼ causes a noise voltage of 10μV. Suppose two input resistance each of 20 Kῼ are connected in parallel, then find the total noise voltage?
5. Modem is combination of both modulator and demodulator.
Explanation: A modem (modulator-demodulator) is used to modulate one or more carrier wave as well as to demodulate them for getting information.
6. Any signal and its Hilbert transform are mutually orthogonal.
Explanation: Consider f(t) be any signal and fh(t) is its Hilbert transform. If we integrate both of them under proper boundary conditions, we get 0 which shows that both are mutually perpendicular i.e.
7. What Squelch circuit does?
a) helps to receive signals that are useful for the system
b) helps to make channel noise free
c) helps to receive two or more than two signals at once
d) helps to suppress the audio output in the absence of sufficiently strong desired signal
Explanation: A Squelch circuit blocks the output in the absence of sufficiently strong desired signal. It is widely used in two-way radios to suppress the annoying sounds.
8. Mostly used radio receivers are?
a) pulsed receivers
b) CW receivers
c) TRF receivers
d) super heterodyne receivers
Explanation: Super heterodyne are radio receivers that uses frequency mixing to convert received signal to a fixed intermediate frequency that can be processed more conveniently. It is also the mostly used receivers.
9. Find the step size of a signal with peak to peak amplitude of 4V and is quantized into 64 levels?
a) 32.3 x 10-3
b) 30.23 x 10-3
c) 62.5 x 10-3
d) 53.3 x 10-3
10. If the step size of a system is 0.0625, find its quantization power?
a) 3.25 x 10-3
b) 3.25 x 10-4
c) 3.25 x 10-2
d) 3.25 x 10-1
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.