Analog Data to Digital Signal (Digitization)

Digitization is the process of converting analog data (like sound, temperature, or images) into a digital signal (a sequence of 0s and 1s) so that it can be processed, stored, or transmitted by digital systems like computers or digital communication devices.

Why Digitize?

• Digital signals are less prone to noise
• Easier to store and compress
• Supports encryption and error detection
• Works with computers and digital networks

Steps in Analog to Digital Conversion (ADC)

1. Sampling

• Take measurements of the analog signal at regular intervals (called sampling rate).

• According to the Nyquist Theorem, the sampling rate should be at least twice the highest frequency in the signal.

 Example: If your voice has frequencies up to 4 kHz, sample at ≥ 8 kHz.

2. Quantization

• Each sample’s amplitude is rounded off to the nearest value within a fixed set of levels.
• This introduces quantization error (a small loss of precision).

3. Encoding

• Each quantized value is then converted into binary (0s and 1s).
• The number of bits used depends on how many levels were defined (e.g., 8-bit = 256 levels).

Final Output

A digital signal — a stream of binary numbers — which represents the original analog data.

Real-life Example

Let’s say you’re digitizing your voice:

• Microphone converts your voice (analog) into an electrical signal.
• ADC circuit samples this signal (e.g., 8000 times per second).
• Each sample is quantized to the nearest level.
• Each level is encoded into a binary number.
• The final digital signal is sent/stored for playback, transmission, or processing.