amdx said:
Is there a sound card available that will generate a frequency as high as
500 Khz?
No, not a 'sound card' - even the most high-end 'professional'
cards run at 196ksps and will only reproduce 90kHz or so. Perhaps
National Instruments or a similar company makes some instrumentation
interface that will output a digitized signal through a D/A at 1msps,
which is what you would need to generate 500kHz.
The highest sample rate of most common soundcards is 48ksps (the
standard for DAT), which means the max frequency it could generate
would be just under half that, or maybe 22kHz.