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