Hi Phil,
Whatever you chose, to get a S/N better than 120 dB will be very difficult. Also noise entering your cabling is very difficult to avoid.
As an alternative for a PCI card you can look at the various USB cards.
If you Google at analog+conversion+pci a load of cards come along. But al professional measurement cards ar no better than 16 bit.
Attached the noise performance of the AD part of my audio card at no input for both channels (8 kHz sample rate). You will clearly see 1/f noise. This is something you cannot avoid due to the properties of semiconductors. The PM1704 is not different.
Whatever you chose, to get a S/N better than 120 dB will be very difficult. Also noise entering your cabling is very difficult to avoid.
As an alternative for a PCI card you can look at the various USB cards.
If you Google at analog+conversion+pci a load of cards come along. But al professional measurement cards ar no better than 16 bit.
Attached the noise performance of the AD part of my audio card at no input for both channels (8 kHz sample rate). You will clearly see 1/f noise. This is something you cannot avoid due to the properties of semiconductors. The PM1704 is not different.
Attachments
I'm not really certain the exact magnitude of the signal and errors you want to measure and replicate as I've seen 10mV, and 0.045uV quoted in these postings, quite an extreme. At the bottom end even a small movement of the cable (if it's not a really low noise cable) can cause the movement of electrons !
It really sounds like a Keithley Instruments, nanovolt source type problem -- you can spend a couple kilobucks and buy one of their units with a 488 type interface.
It really sounds like a Keithley Instruments, nanovolt source type problem -- you can spend a couple kilobucks and buy one of their units with a 488 type interface.
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