Finding the difference equation given the impluse response

In summary, the difference equation is a mathematical formula that describes the relationship between the input and output of a discrete-time system. It can be derived from the impulse response, which is the output of the system when an impulse is applied as the input. The difference equation can be derived from any type of impulse response as long as the system is linear and time-invariant. To find the difference equation, you will need to know the order and coefficients of the system, as well as the initial conditions. However, there are limitations to using the difference equation, as it may not accurately describe complex or non-linear systems and may have limited predictive capabilities for significantly different inputs.
  • #1
lusher00
1
0
This question is for a DSP class. I hope that I am posting somewhere appropriate.

So given the impulse response:

h[n]=((0.5)^n-(0.25)^n)u[n]

find y[n].

Where do I start? I don't need an answer, just a nudge in the right direction.
 
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  • #2
In order to obtain the output, you need the input waveform and the initial conditions. What are they?
 
  • #3


I would approach this problem by first understanding the concepts involved. In this case, we are dealing with digital signal processing (DSP) and impulse responses, which are used to describe the output of a system in response to an impulse input.

To find the difference equation, we need to understand the relationship between the impulse response and the output signal. The impulse response represents the output of a system when an impulse input is applied, while the output signal is the response to any input signal.

One approach to finding the difference equation is to use the convolution sum, which states that the output signal is the sum of the input signal convolved with the impulse response. In other words, we can think of the output signal as the weighted sum of the input signal at different time instants, where the weights are given by the impulse response.

So, to find the difference equation, we can start by writing the convolution sum using the given impulse response and input signal. From there, we can manipulate the equation to isolate the output signal on one side and the input signal and impulse response on the other side. This will give us the difference equation in terms of the impulse response and input signal, which we can then use to find y[n].

I hope this helps nudge you in the right direction. It's important to have a strong understanding of the concepts involved in order to solve problems in DSP. Additionally, seeking guidance and clarification from your instructor or peers can also be helpful in understanding and solving this type of problem.
 

What is the difference equation in relation to impulse response?

The difference equation is a mathematical formula that describes the relationship between the input and output of a discrete-time system. It is commonly used in signal processing and control systems, and it can be derived from the impulse response of the system.

How is the difference equation related to the impulse response?

The impulse response of a system is the output of the system when an impulse is applied as the input. The difference equation can be derived from the impulse response by considering the system as a series of delayed and weighted impulses.

Can the difference equation be derived from any type of impulse response?

Yes, the difference equation can be derived from any type of impulse response, as long as the system is linear and time-invariant. This means that the output of the system is directly proportional to the input and is not affected by a time shift.

What information is needed to find the difference equation from an impulse response?

To find the difference equation from an impulse response, you will need to know the order of the system, the coefficients of the system, and the initial conditions. The order of the system refers to the number of previous inputs and outputs that are used in the difference equation. The coefficients represent the weights given to each input and output in the difference equation. The initial conditions are the starting values of the input and output.

Are there any limitations to using the difference equation to describe a system?

Yes, there are some limitations to using the difference equation. It is only applicable to linear and time-invariant systems, and it may not accurately describe systems with highly complex or non-linear behaviors. Additionally, the difference equation may not be able to accurately predict the behavior of the system for inputs that are significantly different from the ones used to derive the equation.

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