OutPut Pulse Train

[Allister.Stander]

Sketch a Output pulse train for a total period of 500ms if the following settings exist on a pulse generator.Pw=50ms,Time period=200ms,Triggerdelay=20ms,pulse amplitude=10V,DC offset=-5V,Negative Pulse polarity.

 

[crutschow]

So you want us to do the homework for you? We're here to help you with your homework, not do it (notice the title of this forum).

What do you think the waveform would look like? You have the info you need to sketch it.

 

[Allister.Stander]

I u cant help pls donot send funny messages.

Cause its irrating.Pls do not send funny messages in future.

 

[Allister.Stander]

Do not send funny messages if you have nothing to say.

 

[crutschow]

I was not being funny.

I can help you if you tell me what you understand, but I'm not going to do all the work for you.

People that expect us to do all their homework irritate me, so I suppose we are even.

 

[MrAl]

Sketch a Output pulse train for a total period of 500ms if the following settings exist on a pulse generator.Pw=50ms,Time period=200ms,Triggerdelay=20ms,pulse amplitude=10V,DC offset=-5V,Negative Pulse polarity.

Hi,

Maybe you can tell us a little about what you have already done in the past. Have you sketched waveforms before, and if so, what kind?

Apparently they want you to draw the pulse output for 500ms total time period if the settings on the generator have Pw=50ms, period=200ms, delay=20ms, amplitude=10, and DC offset= -5.
This means you have to draw a pulse who's amplitude is 10 with a pulse width of 50ms and total period 200ms after a delay of 20ms, and the offset is going to be a negative 5 volts.

What dont you understand here?

 

[Allister.Stander]

My aswers looks like this.

My ans is in file below

 

[MrAl]

Hello,


Well, the amplitude is 10 and you have that drawn fine, but the DC offset shouldnt invert the signal nor take the whole thing below zero right?

You're very close though, try one more time now...

 

[crutschow]

It looks ok with the correct pulse polarity expect for the offset, which should be plus not minus.

 

[alec_t]

Carl, the OP requirement is offset = -5 and negative pulse polarity. The voltage levels and timing in the sketch look fine to me.

 

[crutschow]

Carl, the OP requirement is offset = -5 and negative pulse polarity. The voltage levels and timing in the sketch look fine to me.

You are correct. The (-) was on the end of the line wrap on my display with the isolated "5" on the next line and I didn't notice it. Thanks for the catch.

 

[MrAl]

Carl, the OP requirement is offset = -5 and negative pulse polarity. The voltage levels and timing in the sketch look fine to me.

Hi alec,

Really? And what makes you assume there should be a 'low' period of 50ms when the PW parameter is 50ms?

He's got it drawn as 50ms 'low' and 150ms 'high' but remember the amplitude should be positive not negative, so it should be 50ms 'high' and 150ms 'low' and this is regardless of the offset. So the wave without any offset would appear as a 50ms pulse (PW=50ms no brainer there), and after the offset is applied it should simply shift the whole signal down 5 units, but it should not invert the logic too.

 

[crutschow]

.....Really? And what makes you assume there should be a 'low' period of 50ms when the PW parameter is 50ms?....

No assumption. The original post stated the pulse was negative polarity.

 

[MrAl]

Hello Carl,

Oh yes that's right, i must have missed seeing that part of the post. It says "negative polarity" so i would assume it's negative but not inverted ('negative' means multiplied by -1 whereas 'inverted' means simply inverted).

So lets see, a 10v amplitude pulse, inverted, is still a 10v pulse, unless they mean "negative polarity" to mean actually negative voltage, in which case his drawing would be correct. Usually if they mean 'inverted polarity' they say 'inverted', not negative, as 'negative' usually refers to a minus signal voltage, but we wont know for sure till he returns and clarifies.

So if the pulse was inverted and shifted by the offset we get one wave, but if the pulse was multiplied by -1 and shifted we get another, different wave (as his drawing).

 

[crutschow]

For a pulse generator output I believe it it common usage to mean that a negative polarity pulse is one that goes from high to low and back, the same as an inverted pulse. Thus a 10V, 50ms pulse with negative pulse polarity, would go from 10V to 0V for 50ms and then back to 10V.

 

[alec_t]

Well if that's the common usage I'll have to go along with it ......under protest . But to my way of thinking a 10V negative polarity pulse should go from 0V to -10V and return to 0V.

 

[crutschow]

Well if that's the common usage I'll have to go along with it ......under protest . But to my way of thinking a 10V negative polarity pulse should go from 0V to -10V and return to 0V.

Either way you get a pulse that is 50ms low and 150ms high. The difference would be how you handle the offset.

 

[MrAl]

For a pulse generator output I believe it it common usage to mean that a negative polarity pulse is one that goes from high to low and back, the same as an inverted pulse. Thus a 10V, 50ms pulse with negative pulse polarity, would go from 10V to 0V for 50ms and then back to 10V.

Hi Carl,

I think you're right there. I've found a couple of pulse generators and the pulses look like they are inverted but unfortunately they all had an unknown offset applied too. I think a better name would have been, "Negative Going Pulse", rather than "Negative Pulse". I guess it may depend on the pulse generator in question also but i havent come across too many of these things to know for sure.