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25/11/2024 13:32PM
Digital Signal Processing Questions and
Answers
Analogue vs. Digital Signals - Answers✓✓Auditory perception = analogue signals stimulating
the auditory system
Digital signals = electronic equipment
Main difference = continuity
-analogue signals are continuous and defined at every instant in time
-digital signals are discrete and defined at only certain instances in time
Advantages of digital signals - Answers✓✓- immune to degradation when copied
- easier to apply signal processing
- easier to store
Analogue to Digital Conversion and Reconstruction (ADC) - Answers✓✓Analog input (sound)
ADC (sampler, discrete-time signal, quantizer)
DSP (digital input to digital output - compression, wind noise filter, adaptive microphones, etc.)
Reconstruction (DAC to low-pass filter)
Analog output
Sampling - Answers✓✓The first process in acquiring a digital signal
- measuring and storing the values of an analogue signal
, ©Themoon EXAM SOLUTIONS
25/11/2024 13:32PM
- Obtained at regular rate as defined by the frequency (fs)
- Each time value associated with each sample can be calculated by knowing then the period
(ps=1/fs)
- Are "held" through the sample period
Sampling Process - Answers✓✓Produces a spectrum that repeats regularly
- Additional frequency components are introduced into the signal as a result
- The frequency components occur in a regular fashion and are "reflected" about the y-axis
(negative frequencies)
Sampling: Nyquist Theorem - Answers✓✓During reconstruction, typically filter out the
repeated versions of the spectrum
- For signal preservation when filtered and reconstructed, it must be sampled at a sufficiently
high rate
- The minimum sampling frequency needed to reconstruct the original signal is equal to 2x the
value of the highest frequency component in the signal.
Quantization - Answers✓✓The process of rounding each of the sampled analogue values
- Rounding is required because digital signals are represented by a restricted number of discrete
values called steps
25/11/2024 13:32PM
Digital Signal Processing Questions and
Answers
Analogue vs. Digital Signals - Answers✓✓Auditory perception = analogue signals stimulating
the auditory system
Digital signals = electronic equipment
Main difference = continuity
-analogue signals are continuous and defined at every instant in time
-digital signals are discrete and defined at only certain instances in time
Advantages of digital signals - Answers✓✓- immune to degradation when copied
- easier to apply signal processing
- easier to store
Analogue to Digital Conversion and Reconstruction (ADC) - Answers✓✓Analog input (sound)
ADC (sampler, discrete-time signal, quantizer)
DSP (digital input to digital output - compression, wind noise filter, adaptive microphones, etc.)
Reconstruction (DAC to low-pass filter)
Analog output
Sampling - Answers✓✓The first process in acquiring a digital signal
- measuring and storing the values of an analogue signal
, ©Themoon EXAM SOLUTIONS
25/11/2024 13:32PM
- Obtained at regular rate as defined by the frequency (fs)
- Each time value associated with each sample can be calculated by knowing then the period
(ps=1/fs)
- Are "held" through the sample period
Sampling Process - Answers✓✓Produces a spectrum that repeats regularly
- Additional frequency components are introduced into the signal as a result
- The frequency components occur in a regular fashion and are "reflected" about the y-axis
(negative frequencies)
Sampling: Nyquist Theorem - Answers✓✓During reconstruction, typically filter out the
repeated versions of the spectrum
- For signal preservation when filtered and reconstructed, it must be sampled at a sufficiently
high rate
- The minimum sampling frequency needed to reconstruct the original signal is equal to 2x the
value of the highest frequency component in the signal.
Quantization - Answers✓✓The process of rounding each of the sampled analogue values
- Rounding is required because digital signals are represented by a restricted number of discrete
values called steps
