Exam Review

Question 1

What is DSP?

Answer 1

Techniques that extract the useful information by processing input digital signals for specific applications.

Question 2

Advantages of Analog Systems

Answer 2

Original signal, seldom interrupting its environment, high speed, no time-delay, less resources involved.

Question 3

Advantages of Digital Systems

Answer 3

Flexible, reliable, stable, repeatable, compatible, available

Question 4

How is DSP implemented

Answer 4

In software or hardware, hardware being faster

Question 5

Difference between Analog systems and Digital systems

Answer 5

Analog systems are continuous in both time and amplitude, Digital systems are limited in both time and amplitude.

Question 6

Three requirements of DSP

Answer 6

Linearity, Causality, Time-invariance

Question 7

Linearity

Answer 7

The sum of outputs produced by each input individually equals to the output produced by the sum of all inputs (for input x = (x1+x2), output = y=a(x1+x2))

Question 8

Time Invariance

Answer 8

Output delay is equal to the Input delay

Question 9

Causality

Answer 9

System’s output depends on present and past data, never on future data

Question 10

What is anti-aliasing filter

Answer 10

low pass filter, removes noise and unwanted signal, uses Nyquist sampling theory to avoid aliasing

Question 11

What is A/D converter

Answer 11

Takes a finite amount of samples using the sample and hold techniques. It will then quantize this value into the relative binary code

Question 12

What is D/A converter

Answer 12

relates the binary values back into an analog signal

Question 13

What is anti-imaging filter

Answer 13

low pass filter that will smooth the output signal from the d/a converter. Removes noise produced by the digital conversion system.

Question 14

Three calculations properties between time and frequency domains

Answer 14

Homogeneity, additivity, multiplication/convolution

Question 15

Steps to get frequency spectrum

Answer 15

Get the 2 sided spectrum with a mirror image, Place the 2 sided spectrum at every multiple of fs

Question 16

Oversampling, undersampling

Answer 16

Taking samples above or below the the Nyquist frequency

Question 17

Describe FIR, IIR, recursive system, and non-recursive system each with one or two sentences

Answer 17

FIR is an open loop system where the number of responses to an impulse is finite. IIR is a system where the number of responses to an impulse is infinite.
A recursive system is one where feedback is used, that is saying it relies on past outputs plus new inputs. A non-recursive system can be said to be an open-loop one.

Question 18

What is the difference between FIR and IIR? What is the difference between recursive and non-recursive system?

Answer 18

No past outputs, always stable. IIR may be unstable, and uses past outputs. It is the same idea for the difference between recursive and non-recursive systems.