# Slew Rate Distortion

Discussion in 'Homework Help' started by Schmitt_trigger, Feb 6, 2013.

1. ### Schmitt_trigger Thread Starter New Member

Feb 5, 2013
20
0
I have another problem that states:

Determine the maximum frequency without distortion that we can get at the output of an ampop with SR=1V/microSecond

a)If the input is a sinuosoid function with 5 V of amplitude

b)If the input is a triangular wave with 5 V of amplitude

I have another problem that states:

Determine the maximum frequency without distortion that we can get at the output of an ampop with SR=1V/microSecond

a)If the input is a sinuosoid function with 5 V of amplitude

b)If the input is a triangular wave with 5 V of amplitude
$

a)

W*Vmax=SR

2*pi*fmax=SR

fmax=(SR)/(2*pi*Vomax)

fmax=31830,98 HZ
$

What would be the difference in the calculations if we have a input that is a triangular wave?

Thanks

2. ### crutschow Expert

Mar 14, 2008
14,843
3,826
With a sinewave you need to differentiate the sinewave to find the maximum slew-rate point since the waveform slew-rate is not a constant. This gives the 2*pi*fmax function.

A triangular wave has a constant slew rate so you don't have to differentiate the signal to find the maximum. It's simply the pp voltage divided by the time for the waveform to go from the minimum to the maximum voltage.

3. ### WBahn Moderator

Mar 31, 2012
19,153
5,177
The problem doesn't provide enough information since the slew rate applies to the output voltage and all that is given is the input waveforms. You also need to know the gain of the circuit.

4. ### Schmitt_trigger Thread Starter New Member

Feb 5, 2013
20
0

So my input signal is $Vi=5*sin*(1*10^6t)$ which differenting gives:$10000000 *pi* cos(2000000* pi* t)$ so the maximum will be $10000000 *pi$ at $t=n/1000000$

How do i know if i have distortion?

5. ### WBahn Moderator

Mar 31, 2012
19,153
5,177
Would the output have to be able to change faster than it is rated in order to keep up with the signal? But don't forget that it is the OUTPUT signal that matters.

6. ### Schmitt_trigger Thread Starter New Member

Feb 5, 2013
20
0

The problem is that i only know the input signal.I know the maximum variation of the input signal but i do not know what is the ouput for that input..

7. ### WBahn Moderator

Mar 31, 2012
19,153
5,177
Then just assume a gain of K and write your result in terms of K.

8. ### Schmitt_trigger Thread Starter New Member

Feb 5, 2013
20
0
So i assume a certain k the multiple it by my input signal.Then calculating the derivative of my ouput signal e check is the value is bigger than the slew rate,rigth?

9. ### WBahn Moderator

Mar 31, 2012
19,153
5,177
Yes, but remember that you have to check the maximum value of the derivative.