Which of the following statements are correct?

A. A multiplier can be used as a balanced demodulator or detector.

B. Dynamic range compression is the process of reducing the peak‐to‐peak variation of a signal to a lower range.

C. An antilogarithmic amplifier is useful for dynamic range compression.

D. In a phase‐locked loop circuit, the capture range is always larger than the lock range. 

Choose the correct answer from the options given below:

Concept:

A multiplier can be used as a balanced demodulator or detector to recover the original message signal from the double sideband suppressed AM signal. The DSB-SC demodulator circuit is shown below:

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Dynamic Compression is a reduction of the range of a signal, meaning that the ratio of the maximum to the minimum levels of a signal is reduced. Hence, dynamic compression reduces the peak-to-peak variation of the signal to a lower range.

Logarithmic Amplifiers compress a large input dynamic range into a smaller range through the use of a logarithmic function. Hence, statement (C) is incorrect.

Once the input frequency is applied the VCO frequency starts to change and adapt to the new input frequency. Hence, PLL is said to be tracking the input. The Lock Range of a phase-locked-loop (PLL) circuit is defined as the range of frequencies over which PLL will track the input frequency signal. The range of input frequencies over which PLL will capture the input signal is referred to as the PLL capture range. Therefore, the lock range is always greater than the capture range as shown below. Hence, Statement (D) is incorrect.

Therefore, only statements A and B are correct.