Acdppt
- 1. SUBJECT: ANALOG CMOS DESIGN Presentation on “ANALOG TO DIGITAL CONVERTER” Presented by, KOTECHAANKITA VIJAYKUMAR ROLL NO:25 ME(VLSI AND EMBEDDED SYSTEM)
- 2. Contents What is ADC? Types of ADCs A/D Conversion Applications.
- 3. What is ADC ? • Definition • Conversion process • Accuracy
- 4. Definition • The analog signals are continuous in nature and can take infinity of values • ADC converts an analog information into a digital information x(t) t
- 5. Conversion process • Sampling • Quantification • Coding
- 6. Sampling • Digital system works with discrete states. • The signal is only defined at determined times. • The sampling times are proportional to the sampling period (Ts). x(t) xs(t) tTs
- 7. • The signal can only take determined values Belonging to a range of conversion (ΔVr) • Based on number of bit combinations that the converter can output • Number of possible states: N=2n where n is number of bits • Resolution: Q= ΔVr/N Quantification t Ts xs(t) ΔVr Q xq(t)
- 8. • Assigning a unique digital word to each sample • Matching the digital word to the input signal Coding t Ts ΔVr Q xq(t) 0 1 2 N-1 N-2
- 9. Accuracy The accuracy of an ADC can be improved by increasing: •The sampling rate (Ts) •The resolution (Q)
- 10. Types of ADCs • Flash ADC • Sigma-delta ADC • Dual slope converter • Successive approximation converter
- 11. A/D Conversion Applications • Microphones - take your voice varying pressure waves in the air and convert them into varying electrical signals. • Thermocouple – temperature measuring device converts thermal energy to electric energy. • Voltmeters • Digital Multimeters
- 12. Thank you……