Analog to Digital Encoding

Analog to Digital Encoding Figure 5-15 Analog to Digital Encoding

Pulse Amplitude Modulation (PAM) Sample analog signal (measuring the amplitude of signal at equal time interval)

Quantized PAM Signal Quantizes the PAM pulse: Assigning integral values in a specific range to sample instances.

Quantizing Using Sign and Magnitude Each value is translated into its 7-bit binary equivalent. The 8th bit indicates the sign

Pulse Code Modulation (PCM) +048 The binary digits are transformed into a digital signal using one of the digital-to-digital encoding techniques

From Analog to PCM

From Analog to PCM

From Analog to PCM

From Analog to PCM

Sampling Rate The accuracy depends on the number of samples taken How many samples are sufficient? Nyquist theorem : The sampling rate must be at least two times the highest frequency of the original signal

Nyquist Theorem A sample rate of twice the frequency of x Hz means that the signal must be sampled at every ½ x seconds