Assignment help - new

[JohnVal]

Please help, i need help with the following assignment, I am new to this and so I am pretty stuck:

This assignment is designed to work on a sampled TTL square wave of up to 100 samples stored in an appropriate array. The two logic states are represented by the following values:

          A logic 1 (High) by a value of 5 + 0.5 (V).

          A logic 0 (low) by a value of 0 + 0.5 (V).

Specification 1 (65%)

To design a VI that will identify every transition between either of the two states and calculate the number of Logic 1s as a percentage of the total number of samples.

The front panel will consist of the following:

          An array of controls holding the sampled values.

          An array of indicators holding the index values of where each transitions occurred.

          An indicator holding the percentage of high values.

Hint: Research Build array and Initialise array functions.

Specification 2 (75%)

To design a VI that will meet specification 1 and can also be used as a sub VI in another VI. The sub VI should be fully documented, have its own icon and connector pane.

Specification 3 (100%)

To design a VI that will meet Specification 2 and will also be capable of detecting any errors that occur: i.e. samples that fall outside the permitted ranges. If errors are detected analysis should be aborted and the samples in error identified in an appropriate manner.

[jcarmody]

Start here.  It'll get you very far.

[JohnVal]

Thanks for that...

But I am asking for help, not a solution! I am pretty stumped.

[dkfire]

And what help are you asking for?

What have you done so far?

What hardware do you have?

What LabVIEW version do you have?

[JohnVal]

A point in the right direction, a starting point.

I was trying to do a paper trace but keep hitting a wall. I made an array but was unsure about which values should go into it. I was trying to find a way to identify the transitions but really am not sure how to do it. And then calculating the number of logic ones as a percentage of the total number of samples is a whole other story...

I am using a PC

Versio 8.6 of labVIEW

[crossrulz]

Shift Registers are your friend here.  Use a shift register to keep track of your transition locations, another one for the number of 1s, and a third for keeping the previous state.  By keeping the previous state, you can check to see if the previous state and the new state are different (a transition occurred).

[JohnVal]

Ok thanks, hopefully a start in the right direction 🙂

[jcarmody]

Here's a quick-and-dirty sample data generator.  It's something to get you started looking for the transitions.

[JohnVal]

Thanks Jim, much appreciated.

[snehaagrawal]

thank you jim