PCM System and Quantization Levels

PCM (Pulse Code Modulation) is a digital modulation technique used for transmitting analog signals in a digital format. In PCM, the analog signal is sampled, quantized, and encoded into a binary format for transmission.

Quantization is the process of converting the continuous analog signal into discrete levels. The number of quantization levels determines the resolution or accuracy of the PCM system. Each quantization level represents a specific amplitude of the analog signal.

Effect of Increasing Quantization Levels on Bandwidth Requirement

When the quantization levels are increased from 2 to 8, the number of discrete levels used to represent the analog signal increases. This increase in quantization levels has a direct impact on the bandwidth requirement of the PCM system.

Explanation:
Increasing the quantization levels from 2 to 8 means that the number of levels used to represent the analog signal increases from 2 (binary) to 8 (ternary). This increase in levels allows for more accurate representation of the analog signal.

Quantization Error:
Quantization introduces an error known as quantization error, which is the difference between the actual analog signal and its quantized representation. Increasing the number of quantization levels reduces the quantization error.

Quantization Step Size:
The quantization step size is the difference between adjacent quantization levels. In a binary system, the quantization step size is relatively large, resulting in a coarse representation of the analog signal. However, in a ternary system with 8 quantization levels, the quantization step size becomes smaller, resulting in a finer representation of the analog signal.

Bandwidth Requirement:
The bandwidth requirement of a PCM system is determined by the highest frequency component present in the analog signal. When the quantization levels are increased from 2 to 8, the finer representation of the analog signal allows for a more accurate representation of high-frequency components.

As a result, the bandwidth requirement of the PCM system increases because more levels are needed to accurately represent the analog signal. In this case, the bandwidth requirement is tripled because the number of quantization levels is increased by a factor of 4 (from 2 to 8).

Therefore, the correct answer is option 'C' - The bandwidth requirement will be tripled when the quantization levels are increased from 2 to 8 in a PCM system.