how can i reach the 200Mbps data transfer rate with my 6537 ?

[cc_file]

sorry, submit 3 times



Message Edited by cc_file on 01-06-2008 07:23 AM

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Message Edited by cc_file on 01-06-2008 07:26 AM

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i have too many questions,  : )

thanks for the above replys, i understand something about 6537.
1)In regards to the "bad" waveform, i probe it use an Oscilloscope with 50 ohms impedance, and the waveform is good !
   your  reply  is excellent !
2)In regards to the sampling clock, i change my 6537 card to a 16x PCI-e slot in the intel DG33FB motherboard and set the sampling clock to 50MHz,  it works !

but i have a new question now.
1)i set the sampling clock to 40MHz \ 41MHz\...\49MHz\50MHz. the actual samling clock i probe at the PFI5 is 40MHz when the setting value is 40-45MHz, it is  50MHz when the setting value is 45-50MHz.  i guess that the sampling clock value  can not be set in small granularity. right ?
2)i test the data acquisition rate in my code as following. the data rate calculated is 190.556 MB/s when the sampling clock  is 50MHz, and it is 152.23 MB/s when clock is 40MHz. these value are not my Expected. i suppose that the data rate is 40MHz*4Bytes(32bit)=160MB/s and 50MHz*4Bytes(32bit)=200MB/s.  why ?

main()
{
    ...
    QueryPerformFrequnce();
    QueryPerformCounter(startTime);
    DAQmxStartTask();
    for(read 1GB data)
    {
       DAQmxReadRaw();
    }
    QueryPerformCounter(endTime);
    duration = endTime - startTime;
    rate = 1GB/duration;
    ...
}

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1)i set the sampling clock to 40MHz \ 41MHz\...\49MHz\50MHz. the actual samling clock i probe at the PFI5 is 40MHz when the setting value is 40-45MHz, it is  50MHz when the setting value is 45-50MHz.  i guess that the sampling clock value  can not be set in small granularity. right ?
      i see.  the frequency is 200MHz/N, N>=4
2)i test the data acquisition rate in my code as following. the data rate calculated is 190.556 MB/s when the sampling clock  is 50MHz, and it is 152.23 MB/s when clock is 40MHz. these value are not my Expected. i suppose that the data rate is 40MHz*4Bytes(32bit)=160MB/s and 50MHz*4Bytes(32bit)=200MB/s.  why ?
     i have made a mistake.  50MHz*4Bytes(32bit)=200*10^6 bit/s = 190.73 MB/s.  the "M" in "MB/s" is 1024*1024.