• Support PF! Buy your school textbooks, materials and every day products via PF Here!

What is the power of unit step signal with magnitude A

  • Thread starter jaus tail
  • Start date
582
43
1. Homework Statement
Find power of signal A u(t)
A is constant like 5, 6 some value.



2. Homework Equations
Power is integration over -T/2 to +T/2 of [x(t)]2 dt
The whole divide by T

3. The Attempt at a Solution
Power is integration over -T/2 to +T/2 of [A u(t)]2dt

The whole divide by T

So 1/T integral A2 dt...integral limits are -T/2 to +T/2
This comes as 1/T A2 integral dt

integral dt is t. limits are -T/2 to +T/2
so integral dt = [T/2 - ( -T/2) ] which becomes T
so Poewr is 1/T * A2 * T
which gives A2

But book answer is A2 /2
Where did the divide by 2 come from?
 

Simon Bridge

Science Advisor
Homework Helper
17,823
1,637
u(t)=1 when t>0 only.
integral is area under the graph - sketch the graph and see...
 

LCKurtz

Science Advisor
Homework Helper
Insights Author
Gold Member
9,473
719
What are ##T## and ##u(t)## in your problem?
 
582
43
u(t) is unit function
u(t) =1 for t > 0 or t =0
u(t) = 0 otherwise.

T is just a random time value. So -T to +T is symmetric about y axis.

Ok now i get it. Since u(t) = 0 for negative time. the integral limit changes from (-T/2 to +T/2) to ( 0 to +T/2).
Got it. Thanks.
 

Want to reply to this thread?

"What is the power of unit step signal with magnitude A" You must log in or register to reply here.

Related Threads for: What is the power of unit step signal with magnitude A

Replies
1
Views
3K
Replies
3
Views
5K
  • Posted
Replies
1
Views
776
  • Posted
Replies
4
Views
6K
Replies
2
Views
831

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top