02-02-2009 03:30 PM
Hello
I have a problem with MultiSIM 9.0.155.
I have built a circuit shown on this picture http://img237.imageshack.us/img237/9764/digitaltoanalogcircutzw1.png.It is supposed to convert a digital (4bit) signal into analog signal (by it's value) so that when the digital signal is 0000 the analog value is 0V, and when it's for ex. digital sig is 1111 the analog value is of 2V... (this circuit uses a two 8-LED bars to indicate which "switch is on", and there isnt an analog signal output yet...)
This circut should work fine, but: When I tried to simulate a 4bit value with a four function generators (with frequencyes set to 1Hz, 2Hz, 4Hz, and 8Hz) the result is something like this:
http://img528.imageshack.us/img528/4268/digitaltoanalogcircutpoig1.png. In this picture the 4 keys are unpressed, and even then i still have a signal like that on the picture...??
I replaced four function gens with 4 batteries as a source but still the signal is the same??...-> an square alternating current with rising and falling edges...
Here is a closer picture with the batteries as a sourcehttp://img300.imageshack.us/img300/9616/digitaltoanalogsourcera4.png.
I don't know if something is not set properly (but it shouldn't get an square signal with the batteries as a source and the 4 keys unpressed), so if anyone sees what's the problem post an answer please..
I have tried to restart MultiSIM but still with the same results...
02-04-2009 09:45 AM
Hi Valdyr;
Could you attach you schematic so I can have a better idea of your connections? I cannot see the connections as clearly as I would like to in the image.
Good Luck
02-05-2009 04:34 PM
here
this is the orig. circut which produces odd signal
the function generators are all set to different frequencies (1khz, 2khz, 4khz, 8khz), but the results are in same freq...02-05-2009 05:25 PM - edited 02-05-2009 05:26 PM
Hi there,
I'm not sure how you created this schematic, but somehow, the 4 nets (a.k.a wires) that you are measuring have the same name! When Multisim starts simulating, it treats all wires by the same name as a single electrically connected wire. That is why you saw the same signal on all 4 channels of your oscilloscope. There is a way to fix this:
I bet there may be other wires in your design that have the same problem. Unfortunately, I think you will have to manually go through your design and find them all.
If you ever find out what you did to make this happen, please let us know. We are always interested to know how to make Multisim easier to use so that mistakes like these don't happen.
Hope that helps!
02-06-2009 10:08 AM
Yes, that did the trick!
Thanks alot..
But unfortunetly I dont know how did I do that. As I remember I just created 4 new wires (by double-clicking on the sheet).
02-06-2009 10:12 AM
Remember to mark a thread as solved once you found the solution to your problem. It helps other forum members when searching for solutions.
Thanks!