LPT oscilloscope questions

Hello,
I have found this little oscilloscope project (URL) that uses a single A/D converter connected directly to the LPT port. It uses one pin of the port as an EXT trigger, which is desirable in my application. The author notified me that it can display signals up to 30-40KHz or so.

1. I wonder, what is the thing that limits the display of signals to 30MHz? Is it this A/D converter or the LPT or both?

2. Is there any way I can convert this to display signals to 30MHz? Any ideas are welcome.

New lpt ports can work till 2 Mhz. Anyway, I think your idea is pointless. USB oscilloscopes is too cheep to spend time for lpt.

Most usb scopes are useless for the HF-and-above radio amateur. Their analogue bandwidth is just too low. Higher grade ones are just too expensive. The cheapest I have found are the hantek ones with 250MHz bandwidth.


Thanks for the port speed. I have found this http://mujweb.cz/elecon/pcoscillosco...illoscope.html It is a nice home brew. I think it can go up to 40MHz of analogue bandwidth, can't it?

Most USB or LPT oscilloscopes are using internal data memory, e.g. that linked in post #3. Respectively the sampling rate isn't limited by the interface speed.