> Dear people of RTL-mailing list, > > We at NBG-Industrial (Location Nederweert, Netherlands) are trying to sample/count a >TTL-signal with a frequency of 200 kHz > (or as high as posssible). We use a PIO-24 card (ISA-based) to generate an interrupt >at > each pulse. The interrupthandler in RTlinux is used to increase a counter. In a >seperate > thread, which starts up every second, the time is measured and the frequency is >calculated. > The precision of the frequency was measured while linux itself was heavily loaded >(compiling > a kernel). 20 kHz is the highest frequency which can be measured without a >deviation. 25 kHz > is still measured reasonably well(a deviation of -6 Hz once in the 200 times). But >frequencies > above 30 kHz are measured with a deviation of minimal 10 Hz almost every measurement >(which > is too large). Is there a way too improve this performance? For instance optimizing >core.c/core.o? > you could use an SMP box and run the data-sampling process on the dedicated CPU 200KHz is posible with this setup - you can run a 200KHz task on a Celeron 400 SMP - but I don't know if you will be happy with the jitter. Also moving to a PCI card could improve things.
hofrat -- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] -- For more information on Real-Time Linux see: http://www.rtlinux.org/
