Can frequency affect conversion time in a system?

[I like Serena]

Yep.

 

[Femme_physics]

But how can I find the resolution based on Va?

My idea was that Va max defines our Vref, but if Vref isn't defined to us we can't tell the resolution and thus can't solve for Va if given a digital output

 

[I like Serena]

What is Vref?
I don't see it in your problem statement.
Or did you mean Vx?

 

[Femme_physics]

Doesn't every D/A has a Vref? How can it function without a analogue input?

 

[I like Serena]

Doesn't every D/A has a Vref? How can it function without a analogue input?

I'm getting confused here.

In your problem statement there is no Vref.

And yes, a DAC would typically have a Vref connected.
Should I assume you mean the voltage that the maximum digital input maps to?

Either way, such a Vref is not really an input, since it is fixed and usually not shown.

 

[Femme_physics]

I'm getting confused here.

In your problem statement there is no Vref.

And yes, a DAC would typically have a Vref connected.
Should I assume you mean the voltage that the maximum digital input maps to?

Either way, such a Vref is not really an input, since it is fixed and usually not shown.

So to find the resolution of the converter I just use Va Max?

 

[I like Serena]

So to find the resolution of the converter I just use Va Max?

I'm still confused.

Which resolution?
What would Va Max be?

 

[Femme_physics]

Suppose Va max is 5. The binary output of the converter in question (the one at the original message) is 01001101. I am asked to find Va in that case. You're asking me "what resolution", but You can't solve it without one because you have the formula Va = Resolution x Output in base 10


Hmm... Do you follow me?

 

[NascentOxygen]

I'm asked to calculate Va, if the counter output is (01101110)2

In the absence of a specified Vx _max (or Va _max) you could express your answer in terms of "Vx _max", the maximum analog output available from the DAC.

So, if 11111111 → Vx _max,
then 01101110 → k⋅Vx _max
Find k.

You should be able to express resolution in terms of Vx _max

I'm not sure how punctilious one should be in answering this question. But for the comparator to stop the action, Vx necessarily must always be able to exceed Va, so this implies Va _max < Vx _max

 

[I like Serena]

Suppose Va max is 5. The binary output of the converter in question (the one at the original message) is 01001101. I am asked to find Va in that case. You're asking me "what resolution", but You can't solve it without one because you have the formula Va = Resolution x Output in base 10Hmm... Do you follow me?

Do you have a problem statement?

To find the Va that corresponds to (01001101)₂ you would need the maximum Vx output your DAC can give.

 

[Femme_physics]

Hi ILS, NasO, I'll clarify the question...


"The following is a main scheme of an A/D converter with 12 bits. Max Va is 5 [V].

In the A/D converter's output, the binary digit 010111110110 was measured. Calculate, what's Vin that was converted to this binary. "

Answer:

IMO I just do this


http://img834.imageshack.us/img834/1905/vinconversion.jpg

Whereas in the formula for resolution

Res = Vmax - Vmin / 2ⁿ = 5 / 2¹² = 0.0012207

Therefor I consider Va max = the Vmax of the converter and use this resolution to reach the answer.

 

[NascentOxygen]

Looks right to me!

 

[Femme_physics]

Thanks NasO2 :)