I have run into another problem using the adc212/100 in VB6. In the system I am developing, I have set up a virtual oscilloscope using the adc212.
I am looking at repetitive ultrasonic signals and notice a big change in signal shape when I move from digitizing at 50MHz to 100MHz. At 100MHz the signal appears "jagged". The general shape of the signal is the same, but, instead of a smooth line it is jagged. At first, I thought it was high frequency noise of some sort. After attempting to average, I found that this occurrence was repetitive and could not be averaged out. At any lower digitization rate this affect does not show up - only at 100MHz. Note that when I load the Picoscope software and view the signal there, the signal is as expected - smooth. Also, the affect does not show up on a Tektronix scope.
Is situation symptomatic of any common programming errors with the adc212?
To further investigate this, I modified the visual basic example program to work from an external trigger, digitize at 100 MHZ (timebase = 0), and collect 4096 samples. These are settings I have been working with previous to now. The same jagged affect occurs.
I am nearing my deadline so any expedited help you can give me would be invaluable.