ADC (Analog to Digital Converter): Converts analog signals into digital signals.
DAC (Digital to Analog Converter): Converts digital signals into analog signals.
Everyday Use
Smartphones: Streaming music (DAC), microphone for voice (ADC).
Telephone Communication: ADC for converting voice to digital for transmission, DAC for converting received digital to analog so it can be heard.
Importance of ADC and DAC
Analog signals (e.g., temperature, pressure, sound) need to be converted to digital for easier processing, storage, and noise reduction.
Analog vs Digital Signals
Analog Signals: Continuous in time and amplitude, susceptible to noise, difficult to process and store.
Digital Signals: Discrete in time and amplitude, less susceptible to noise, easier to process and store.
Conversion Process
Sampling: Analog signal is sampled at a particular rate.
Quantization: Sampled signal is assigned a value from a discrete set of values.
Encoding: Quantized signal is encoded in binary format.
Quantization
Signal gets quantized into discrete levels.
Resolution: Number of bits used to represent the signal (higher bits = higher resolution).
Example: For a 3-bit ADC with a 10V range, resolution is 1.25V; a change less than 1.25V is undetectable. For a 3-bit ADC with a 1V range, resolution is 125mV.
Transfer Function: 3-bit ADC with a 1V range – quantization error can be up to ±0.125V.
Quantization Error: Error due to conversion, typically ±1 LSB, can be reduced by increasing resolution or using techniques to shift transfer functions.
Sampling
Sampling rate should be ≥ 2x the maximum frequency of the input (Nyquist theorem) to avoid aliasing.
Anti-aliasing Filter: Used to filter out high-frequency components to avoid aliasing.
Sample and Hold Circuit: Ensures signal remains constant during processing.
Digital to Analog Conversion
DAC Operation: Converts digital bit stream to analog signal.
Accuracy: Dependent on the resolution of the DAC (e.g., 12-bit DAC more accurate than 3-bit DAC).
Important Parameters: Resolution, reference voltage, settling time (impacts max frequency).
Other Parameters: Gain and offset error, non-linearity, total harmonic distortion.
Types of ADC and DAC
Different designs offer various advantages (better resolution, faster conversion, etc.).
Will discuss different types and designs in future videos.
Conclusion
ADC/DAC: Essential for converting signals for processing and storage in electronics.
Future Topics: In-depth look at different types of ADCs and DACs, important parameters, and design advantages.