Communication Systems MCQ Questions & Answers | ECE

Consider the following statement with regard to a PLL:
1. The 'capture range' of a PLL primarily depends upon the slope of transition band edge of the low-pass filter
2. The 'lock range' is not affected by the slope of transition band of the low-pass filter.
Which of the above statements is/are correct?

What is the typical bandwidth of a 2-wire telephone line?

For an FM demodulator circuit with a transfer function 0.2 V/kHz and an FM input signal with 20 kHz of peak frequency deviation, the peak output voltage is

. . . . . . . . technique is used for blurring and for noise reduction.

A 400 W carrier is VSB modulated to a depth of 100%. Calculate the total power if 20% of the other sideband is transmitted along with wanted sideband

Consider a communication scheme where the binary values signal X satisfies P{X = 1} = 0.75 and P{X = -1} = 0.25. The received signal Y = X + Z, where Z is Gaussian random variable with zero mean and variance σ². The received signal Y is fed to the threshold detector. The output of the threshold detector \[{{\rm{\hat X}}}\] is
\[{\rm{\hat X}} = \left\{ \begin{array}{l} + 1,\,\,\,{\rm{Y}} > \tau \\ - 1,\,\,\,{\rm{Y}} \le \tau \end{array} \right.\]
To achieve a minimum probability of error \[{\rm{P}}\left\{ {{\rm{\hat X}} \ne {\rm{X}}} \right\}{\rm{,}}\]   the threshold τ should be

Match List-I with List-II and select the correct answer using the options given below:

List-I (Communication Service)	List-II (Bandwidth)
a. AM Broadcast	1. 10 kHz
b. Telephone	2. 4 kHz
c. Wideband FM	3. 200 kHz
d. TV	4. 7 MHz

AM broadcast systems use a SW band that extends from:

Which one of the following statements is correct?

An AM signal and a narrow-band FM signal with identical carriers, modulating signals and modulation indices of 0.1 are added together. The resultant signal can be closely approximated by