[digital signal processing] discrete time signal (analog signal, discrete time signal, digital signal | sampling leads to time discrete | quantization leads to amplitude discrete)

One 、 analog signal 、 Discrete time signals 、 digital signal

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Time is continuity Of , The amplitude is also continuity Of , The signal is analog signal or Continuous time signal ;

Time is discrete Of , The range is continuity Of , The signal is Discrete time signals ;

Time is discrete Of , The range is discrete Of , The signal is digital signal ;

Two 、 Sampling leads to time dispersion

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Sampling leads to time dispersion :

Time dispersion is caused by sampling , Such as audio sampling 44100 Hz , One second sampling 44100 Audio samples , Even so , Time is also discrete ;

Time is discrete , If the amplitude is continuous , Description: values can be taken $f(t)$ Corresponding $y$ Any point on the axis , The signal is Discrete time signals ;

3、 ... and 、 Quantization leads to amplitude dispersion

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Quantization leads to amplitude dispersion :

Dispersion of amplitude , refer to , Sampling value of the signal , Can only be given a few values , Such as audio sampling bits 8 position , Then the value range of audio sampling can only be 0 ~ $2^8$ Between the value of the , Cannot take value 0.0001 This value ;

The following figure The signal on the left yes Discrete time signals , Its time is discrete , The time value can only be Integers , however The amplitude value can be 52 ~ 64 Any value between , Such as 0.0001 Value ;

The following figure Signal on the right yes digital signal , Its time and amplitude are discrete , The time value can only be Integers , The range value can only be an integer ;

take Continuous amplitude value To Discrete amplitude values The process of quantitative ;