Conecpt Flashcards

Conecpt Flashcards#

1. What is the difference between analog and digital signals?

Analog signals are continuous and can take on any value within a range.
Digital signals are restricted to a finite set of discrete values.

2. What is binary?

Binary is a digital system that uses only two possible values, typically 0 and 1.

3. List three advantages of digital signals.

  • Less susceptible to noise

  • Easily stored and recovered

  • Easier encryption and signal processing

4. What is the main disadvantage of converting analog to digital?

Information is lost because a continuous range of values must be mapped to discrete levels.

5. What are the three steps of analog-to-digital conversion?

  1. Sampling

  2. Quantizing

  3. Encoding

6. What is the sampling rate?

The sampling rate, \(f_s\), is the number of samples taken per second when measuring an analog signal.

7. What is the Nyquist sampling criterion?

To avoid aliasing:

\[ f_s > 2f_{\text{High}} \]

The sampling frequency must be greater than twice the highest frequency in the signal.

8. What is aliasing?

Aliasing is distortion that occurs when a signal is sampled below the Nyquist rate, causing high-frequency components to appear as lower frequencies.

9. How can aliasing be prevented?

  • Use a sampling frequency above the Nyquist rate

  • Add a low-pass (anti-aliasing) filter before the ADC

10. What determines the number of quantization levels in an ADC?

The number of bits, \(b\):

\[ \text{levels} = 2^b \]
11. What is ADC resolution?

Resolution is the smallest voltage change that can be detected:

\[ \Delta V = \frac{V_{\max} - V_{\min}}{2^b} \]
12. Why is a smaller resolution considered better?

A smaller \(\Delta V\) means smaller quantization steps and less quantization error.

13. What is the dynamic range of an ADC?

The dynamic range is the voltage span from \(V_{\min}\) to \(V_{\max}\).

14. What is quantization error?

Quantization error is the difference between the actual sampled voltage and the nearest allowed discrete level. The maximum quantization error is:

\[ QE_{\max} = \Delta V \]
15. How do you determine the quantized level of a sample?

First compute the expected level:

\[ EL = \frac{V_{in}(t) - V_{\min}}{\Delta V} \]

Then truncate:

\[ QL = \lfloor EL \rfloor \]

Finally, encode \(QL\) into a \(b\)-bit binary number.