http://www.oscilloscope-lib.com/Osc_DLL_VB.zip
just take it.

Speedy performance.
The library makes it possible to show on the beams of the oscilloscope over a million quantization steps of signal per second (on the Pentium III machine) – less than one micro-second is sufficient for one signal sample. This software can be used for linking to real-time controlling programs as longer delays in relay of data to the oscilloscope...