TTMER13: Picture coding methods

Control questions

To fulfil this measurement it is necessary to have some knowledge of earlier subjects in the curicullum. The existence of this knowledge is controlled at the beginning of the measurement, because the shortage of this basic knowledge cannot be made up. You have to answer 5 questions at the beginning of the laboratory exercise. One wrong answer will make the mark given to the measuring with one grade worse. Two or more wrong answers will result a supplementary measuring! In topics according to the measurement (and the questions) materials in the references - especially [7] - can provide appropriate information and preparation possibilities.

In formulas featuring in the following questions frequency f should be substituted in Hz, while the measure of s(f) is mV2/Hz.

  1. What does the sampling theorem declare?
  2. How can the alias "signal" grow up?
  3. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. Draw the spectrum of this signal (even in a negative domain)!
  4. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. This signal is filtered with a first order low-pass filter, and the cut-off frequency of this filter is 3800 Hz-s. Draw the spectrum of this signal (even in a negative domain)! (Drawing can be prepared at home in advance, and can be given with the student's name on it!)
  5. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. This signal is filtered with a first order low-pass filter, and the cut-off frequency of this filter is 1800 Hz-s. Draw the spectrum of this signal (even in a negative domain)! (Drawing can be prepared at home in advance, and can be given with the student's name on it!)
  6. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 22.05 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -50-+50 kHz-s!
  7. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 8 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -20-+20 kHz-s!
  8. There is given a base band signal, that has a spectrum, which we can describe between 300 Hz-s and 3600 Hz-s with the s(f)=7-f/900 formula, while between 0 and 300 Hz-s, and over 3600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 7 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -25-+25 kHz-s!
  9. There is given a base band signal, that has a spectrum, which we can describe between 8300 Hz-s and 11600 Hz-s with the s(f)=7-(f-8000)/900 formula, while between 0 and 8300 Hz-s, and over 11600 Hz-s its value is 0. Draw the spectrum of this signal (even in a negative domain)!
  10. There is given a base band signal, that has a spectrum, which we can describe between 8300 Hz-s and 11600 Hz-s with the s(f)=7-(f-8000)/900 formula, while between 0 and 8300 Hz-s, and over 11600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 7 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -25-+25 kHz-s!
  11. There is given a base band signal, that has a spectrum, which we can describe between 8300 Hz-s and 11600 Hz-s with the s(f)=7-(f-8000)/900 formula, while between 0 and 8300 Hz-s, and over 11600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 8 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -20-+20 kHz-s!
  12. There is given a base band signal, that has a spectrum, which we can describe between 8300 Hz-s and 11600 Hz-s with the s(f)=7-(f-8000)/900 formula, while between 0 and 8300 Hz-s, and over 11600 Hz-s its value is 0. Make a sampling for the signal with a sampling frequency of 44.1 kHz-s. Draw the spectrum of the sampled signal (even in a negative domain) between -50-+50 kHz-s!
  13. What is the origin of the quantization noise?
  14. Why is it advantageous to use the logaritmic quantization?
  15. What is the quantization noise of a delta stair-sized uniform quantizer?
  16. Why the signal-to-noise ratio calculable from the quantization noise depends on the crest of the signal to be quantified?
  17. How can we imagine the time function or spectrum of a sinusoid signal with an equally growing frequency in one time? What happens, if we make a sampling for this signal?