Difference Equation And Filtering

Question 1

Linear Systems

Answer 1

Systems that obey superposition. Y will be the sum of X amount of outputs produced by X amount of inputs

Question 2

Casual Systems

Answer 2

Outputs dependent of present and previous data.

Question 3

Time Invariant

Answer 3

The output delay will be the same as the input delay.

Question 4

Difference Equation

Answer 4

Describes how a linear, time-invariant, casual digital filter works.

Question 5

Filter Coefficients

Answer 5

Set of constants also called tap weights, used to multiply against delayed signal sample values within a digital filter structure

Question 6

Recursive Filter

Answer 6

When a digital system relies on inputs and past outputs.

Question 7

Non-Recursive Filter

Answer 7

When the digital filter relies on inputs and not on past outputs.

Question 8

Impulse Response

Answer 8

When the input to a filter is a unit impulse function, the output from the filter is the unit impulse response.

Question 9

Infinite Impulse Response (IIR)

Answer 9

Because new outputs are dependent of old outputs, the impulse response never dies. Typical for recursive diff. equations.

Question 10

Finite Impulse Response (FIR)

Answer 10

Characteristic of non-recursive filters. Uses past inputs but no past outputs to calculate new outputs. This type of response becomes zero.

Question 11

Moving Average Filter

Answer 11

Impulse response averages every n samples in the input signal.

Question 12

Step Response

Answer 12

S[n].

Response level of system changes at input. This is a filters response to a unit step function.

Question 13

Roll Off

Answer 13

The steepness of a filters response in transition region from pass band to stop band.

Question 14

Stop Band

Answer 14

A band of frequencies attenuated by a digital filter. This occurs where filter gains are low.