looking for DAQ that measures PPM tia sal22

can anyone recomend one?

Could you elaborate on exactly what you want to do?

Best regards,

Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, FREE Signal Generator Pitch Track, Pitch-to-MIDI DaqMusic - FREE MUSIC, Forever! (Some assembly required) Science (and fun!) with your sound card!

time, can anyone recomend one?

Not really clear here what you are asking for. DACs output voltages, and ADCs measure them.

Old Solatron 7060 voltmeter secondhand, provided you don't want absolute calibration will just about do it on the 10v range (as will some of the later models but they are usually more expensive).

It is actually rather hard to get ppm low noise ADCs to behave reliably at 6 sig figs and you need reference gear to qualify and calibrate it.

Regards, Martin Brown

time, can anyone recomend one?

Depending on what he really wants, the OP may want to look into averaging methods. I have a series of articles on synchronous waveform signal averaging, starting at:

The articles are about recovering a repeating waveform that is buried in noise, but the noise reduction and bit resolution principles apply equally to simpler measurements, if that's what the OP is looking for.

Basically, for every doubling of the number of samples averaged, the noise goes down by 3 dB and the resolution is increased by 1 bit. Note that this assumes that any drift in the ADC is of much longer duration than the thing you are looking for.

Interestingly, you can make an "ADC" that has only a *single bit* and get high-resolution results using averaging. Here you actually use noise (either in the signal being measured, or deliberately added as "dither") to improve the resolutiuon. See:

Best regards,

Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis

Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, FREE Signal Generator Pitch Track, Pitch-to-MIDI DaqMusic - FREE MUSIC, Forever! (Some assembly required) Science (and fun!) with your sound card!

I'm just looking for a DAQ that can measure PPM

They have portable versions but I'm looking for a DAQ version so I can export data to a text file over time.