Process

Process

1. DAC

   • is presented in binary form
   • EJ: Compact disc.
     • computer, cellphones, TVs are others electronics aparats that use DAC
   • Transform digital signals in analogic tension
     • it must be converted in an analogic signal and aplicated to speakers who will converter the analogic signals throught its mecanic moviments in audible signals.
     • The time in which the changes is called Period of Sampling (Ts)
   • the input signal is processed with an electronic low-pass filter to remove all frequencies above the Nyquist frequency. This is done to prevent aliasing during sampling, and is correspondingly called an antialias filter.
   • Single Bit Data Conversion
     • A popular technique in telecommunications and high fidelity music reproduction is single bit ADC and DAC.

2. ADC

   • consists in the transcription of analog signals in digital signal, with the purpose of facilitating their processing
   • A computer can not interpret analog signals, so it must be translated into binary signals.
   • graphic compression
     • JPEG
       • uses the illuminance and not the chrominance, the brain is more sensitive to changes in brightness than to changes in colors.
     • GIF
       • uses a palette of 265 colors
   • Dithering
     • is a common technique for improving the digitization of these slowly varying signals.
       • a small amount of random noise is added to the analog signal.
         • the added noise is normally distributed with a standard deviation of 2/3 LSB, resulting in a peakto- peak amplitude of about 3 LSB.

3. These process are inverse

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