CS - 601 || CS -601 Quiz # 2 Solved by Vicky Lab || CS601 2020

Solution File:

Analog-to-Digital Conversion

o We sometimes need to digitize an analog signal

o To send human voice over a long distance, we need to digitize it, since digital signals are less prone to Noise

o This is called Analog-to-Digital Conversion or Digitizing an Analog Signal

o This type of conversion requires a reduction of  potentially infinite number of values in the analog signal so that it can be converted to digital bit stream with minimum loss of information.

o CODEC Æ Coder Decoder o Digital signal signals can take any of the forms discussed previously o Problem is how to convert analog signal from infinite number of values to discrete no. of values without scarifying quality

Pulse Amplitude Modulation 

o First step in Analog-to-Digital Conversion o This technique takes an Analog signal, Samples it, and Generates a series series of Pulses based on the results of Sampling o Sampling means measuring amplitudes of signal at equal intervals

o The original signal is sampled at equal intervals 

o PAM uses a technique called Sample & Hold means At a given moment , signal level is read, then held briefly

o The pulses are of any amplitude (still analog not digital). To make them digital, we need PCM 

Pulse Code Modulation 

o Modifies pulses created by PAM to a complete digital signal

o Four Separate Processes:

PAM

Quantization

Binary Encoding

Digital/Digital Encoding 

Quantization PCM’s first step is Quantization 

“Quantization is a method of assigning integral values in a specific range to sampled instances”