Test and Measurement Forum


Which product is right for your exact requirements


Postby mray » Fri Aug 20, 2004 6:45 pm

I am looking for a PC scope capable of measuring duty cycle of a 15V/500 HZ square wave. The duty cycle is checked at three percentage levels, 10%, 50% and 90%. The accuracy required will be 1.8 +/- .036 mseconds for 90%, 1.0 +/- .020 mseconds for 50% and .200 +/- .004 mseconds for 10%. The normal procedure is to connect the signal to a scope and adjust it to the above tolerances. My main question is this possible with one of your PC scopes. If not, please let me know what tolerances are capable at each level. The other measurement that will have to be made is a 10 V PK-Pk sine wave at 3847.5 HZ to a +/- 120 HZ. I would think that this wouldn't be a problem with any of your scopes. Please let me know the which scope is required. I will need dual input with internal triggering (minimum). We are currently using a digital scope but I would like to replace it with a PC scope and use the digital scope for another application. I was looking at the ADC-100, ADC-42 and Picoscope 3204. How about calibration? Is there away verify the calibration periodically.


Michael V. Ray
Sr. Electrical Engineer, Controls
Westinghouse Air Brake Company
(864)433-6326 (W)
(864)433-9619 (F)
Posts: 1
Joined: Fri Aug 20, 2004 5:14 pm

Postby Sarah » Wed Aug 25, 2004 8:50 am

Hi Michael

Thank you for your post.

For your application I would actually recommend using the ADC-212/3 oscilloscope. This is a dual channel scope and would provide you with sufficient bandwidth and accuracy to measure the signals you wish to measure. It has a maximum sampling rate of 3MS/s and 32k of internal buffer memory.

The ADC-42 would not be suitable as it is a single channel oscilloscope and the ADC-100 does not have an internal clock so would not be able to provide you with the accuracy that you desire.

The main consideration you should make is the triggering. Picoscope can only trigger on one channel at a time, therefore the second channel cannot be triggered if the first is.

Hope this helps

Best Regards

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