Signal to quantization noise ratio (SQNR) in PCM system

Signal to quantization noise ratio (SQNR) is an important parameter in pulse code modulation (PCM) system which determines the quality of the digitized signal. It is defined as the ratio of the power of the input signal to the power of the quantization noise. It is expressed in decibels (dB) and higher the value of SQNR, better will be the quality of the digitized signal.

Factors affecting SQNR in PCM system

There are several factors that affect the SQNR in PCM system, including:

1. Number of quantization levels: SQNR is directly proportional to the number of quantization levels used in PCM system. Higher the number of quantization levels, higher will be the SQNR and better will be the quality of the digitized signal.

2. Signal bandwidth: The SQNR is indirectly proportional to the signal bandwidth. Higher the signal bandwidth, lower will be the SQNR and the quality of the digitized signal will be affected.

3. Sampling rate: The SQNR is independent of the sampling rate used in PCM system. However, higher the sampling rate, better will be the quality of the digitized signal.

4. Nature of carrier wave: The SQNR is independent of the nature of the carrier wave used in PCM system.

Conclusion

In conclusion, the number of quantization levels is the most important factor that affects the SQNR in PCM system. It is essential to use a sufficient number of quantization levels to achieve a high SQNR and good quality of the digitized signal. The signal bandwidth also plays a crucial role in determining the SQNR, and it is necessary to limit the signal bandwidth to achieve a high SQNR. The sampling rate is less critical, but a higher sampling rate can improve the quality of the digitized signal.