Digitalisation of signals: answers

I. The step order for the analogue to digital conversion is:

  1. Quantization/sampling/compression/coding
  2. Sampling/quantization/compression/coding
  3. Sampling/compression/quantization/coding


II. On a theoretical point of view, sampling a signal s(t) is equivalent to multiply it by:

  1. the signal s(t) itself
  2. a Dirac impulse
  3. a Dirac "comb"


III. Let Fe be the sampling frequency and Fmax the maximum frequency contained in the signal. Which is the sampling condition (Shannon-Nyquist)?

  1. Fe = 2*Fmax
  2. Fe >= 2*Fmax
  3. Fe <= 2*Fmax


IV. Multiplying two signals s(t) and f(t) in the temporal domain is equivalent to which operation in the frequency domain?

  1. Making a convolution between s(w) and f(w)
  2. Adding s(w) and f(w)
  3. Substracting s(w) from f(w)


V. The operation which ensures the transformation from real values to normalised sample amplitudes is called:

  1. Coding
  2. Quantization
  3. Compression



Texte - Copyright © 1996, 1997 DECLE & BURTAIRE

Texte - Copyright © 1997, 1998 JACQUEMIN & PETETIN