Correct Answer - Option 4 : Number of bits used for quantization
PCM:
- PCM (Pulse Code Modulation) is a digital scheme for transmitting analog data.
- The amplitude of an analog signal can take any value over a continuous range, i.e. it can take on infinite values.
- But, digital signal amplitude can take on finite values.
- Analog signals can be converted into digital by sampling and quantizing.
The signal to noise ratio of a PCM system is given by:
SNR = 1.8 + 6n dB
n = Number of encoded bits used.
As the number of encoded bits increases, the SNR is improved and hence the accuracy also improves.
Also, the number of levels used by the quantizer is given by:
q = 2n
In general,
Quantization noise power of a Quantizer is given by
\(Q = \frac{{{\Delta ^2}}}{{12}}\)
∆ = step size of the Quantizer
\(\Delta = \frac{{{V_{P - P}}}}{{{2^n}}}=\frac{V_{p-p}}{L}\)
Vp-p: peak to peak voltage
L: Number of quantization levels.
n: Number of bits used in Quantization.
