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Making a Frequency Measurement with an Analog Input Channel

Primary Software: LabVIEW Development Systems>>Full Development System
Primary Software Version: 7.1
Primary Software Fixed Version: N/A
Secondary Software: N/A
Hardware: Multifunction DAQ (MIO)>>Basic>>DAQPad-6015 for USB

Problem:
How can I perform a simple frequency measurement with an analog input channel?

Solution:
Some data acquisition cards have limited counter input capabilities, such as the DAQPAD 6015. Due to limited FIFO buffers, absence of DMA channels, and other miscellaneous reasons, some cards may not be able to perform higher frequency measurements.

A simple workaround in these cases would be to acquire the signal as an analog input, then perform some spectral analysis. A good starting point would be the ContAcq&Graph Voltage-Int Clk shipping example. One can take the data signal from the DAQmx Read and wire it to the Tone Measurements express VI for a numeric output of the frequency. Also, one can use the Spectral Measurements express VI to display an FFT graph of the signal. Refer to the Related Links section below for an illustration of this implementation.

Related Links:

Attachments:


- Simple Analog In Freq Meas.vi


Report Date: 11/18/2005
Last Updated: 01/12/2007
Document ID: 3RH83JJQ

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