Hi there! I am trying to read the output of a lock-in amplifier that can not be interfaced to my PC. So i decided to read througn my microphone input. For this, I connect channel 1 or 2 to my mic input. However each time i do a read i cannot just grab one point but only several points at a time. 10 is the min number of points i can get when i set sample rate 100 and duration 0.1 in the Acquire Sound VI. Any combination that results in less than 10 points gives me an error (e.g 100 sample rate and duration 0.01). I thought that by indexing the dynamic data coming out from Acquire Sound VI would solve the problem but the reading is differnet from the one i get when reading the lock-in amplifier through GPIB. (i am testing by using a lock-in amplifier which i can interface through GPIB. So I simultaneously read with my sound card and the GPIB and compare the graphs) Any way to read one point each time? Or am i getting something else wrong here? Thanks for your time!

Looks like the min freq responce of the ADC is 10Hz, pg 69 of the spec sheet: http://www.hardwaresecrets.com/datasheets/ALC888_1-0.pdf Though you may want to apply a known value of low DC voltage to the mic input to see if it reads properly. Note that mics output low level signals, looks like the ADC full scale input is ~1-1.5V so make sure your input does not exceed that. You could use resistive voltage dividers if needed to scale down the input voltage. -AK2DM

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Read one data point each time via sound card

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Thank you for confirming what some of us were guessing.

It sounds like you either need to get a GPIB interface for your computer or a DAQ card which can measure the DC values.

Lynn

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Read one data point each time via sound card

Re: Read one data point each time via sound card