1. Analog to Digital Conversion
Meredith Matteson, Lenoir City High School
Mentor: Aysha Shanta
Young Scholars Program
July 22, 2016
The University of Tennessee Knoxville

2. Outline Practical Applications Signals Analog signals Digital signals
Conversion of Analog signals to Digital signals
Sampling
Nyquist - Shannon Sampling Theorem
Quantization
Coding
Project and Conclusion

3. Application Common examples Telephone Television Radio Computer Camera
Video Recorder

4. Signal
Defined as as any physical quantity that varies with time, space, or any other independent variable or variables.
The X-axis is the time and the Y-axis represents some other vector characteristic.
Represented by a function (Examples: cosine or sine)

5. Analog Signal
Analog - of or relating to a device or process in which data is represented by physical quantities that change continuously. [1]

6. Digital Signal
Digital - of or relating to information that is stored in the form of the numbers 0 and 1. [2]

7. Analog to Digital Conversion
Sampling
Quantization
Coding
[6].

8. Data at regular X - axis intervals Discrete time
Sampling
Data at regular X - axis intervals
Discrete time
[6].
Analog Digital

9. Importance of Frequency in Sampling
Time period - time it takes for the signal to come back to the starting point
Frequency = 1/time period
Direct relationship between frequency and sampling rate
Shows the difference between high and low frequency waves. [3]

10. Nyquist - Shannon Sampling Theorem
Fsample > 2 * Fmaximum
If the maximum frequency is 100 Hz, the sample frequency must be at least 200 Hz.

11. Importance of Sampling
Inappropriate number of samples can cause a false reconstruction.
Solid line is actual wave. Broken line is reconstructed line. [5].

12. Defined levels on the Y axis Levels = 2number of bits
Quantization
Defined levels on the Y axis
Levels = 2number of bits
Quantization error
Loss of data
Discrete Time Signal
[7].
Quantized Signal that has been forced onto levels.

13. Coding
Binary Sequencing on the Y axis
Defined by a certain number of bits
Digital devices only recognize 1’s and 0’s.

14. Analog Voice Recording

15. Comparison of the Original Analog signal to the Sampled Signal

16. The Digital Signal with a 4 bit quantizer

17. Comparison of all three signals

18. Conclusion
Analog to Digital Conversion allows for any set if continuous data to be transmitted and processed digitally.
3 Step Process
Sampling
Quantization
Coding
Audio Recording

19. References
[1]. Analog vs. Digital [Graphic of just the analog signal]. (n.d.). Retrieved July 5, 2016, from digital/digital-signals
[2]. Digital.signal.discret.svg [Graphic of a digital signal]. (2014, August 27). Retrieved July 5, 2016, from
[3].Experiment 01: Sampling and Quantization of signals using MATLAB. (n.d.). BRAC University. Retrieved July 13, 2016.
[4]. [Graphic of a low frequency curve and a high frequency curve]. (n.d.). Retrieved July 5, 2016, from
[6]. Marshall, D. (2001, April 10). Nyquist's Sampling Theorem. Retrieved July 13, 2016, from
[5]. Kunath, S. (n.d.). Analog to Digital Conversion [Image of Analog and Digital signal side by side.]. Retrieved July 5, 2016, from
[7]. Proakis J.G. and Manolakis D. G. (1996). Digital Signal Processing: Principles, Algorithms, and Application. New Jersey: Prentice-Hall, Inc.
[8]. 007 Signal Path Series. (2013). Retrieved July 15, 2016, from

20. Any Questions?

21. Acknowledgements
This work was supported primarily by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC
Other US government and industrial sponsors of CURENT research are also gratefully acknowledged.