Data

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Data Acquisition and Filter Design (1.6)

Students Manual This is a veiled introduction to data acquisition. Furthermore, students will be exposed to the ideas of filtering, noise, sampling and autocorrelation.Students will be required to analyze the autocorrelation of the noise signal, generated from a pseudorandom binary signal. This will be followed by low-pass filtering using a simple RC circuit and calculating the autocorrelation of the filtered signal.
Matlab Codes Nyquist
Lab View Code Filter
Sample Results Gain of a low pass filter as a function of frequency
Circuit Diagram Circuit for pseudo-random noise generation based on shift registers
Further Readings and References "Two student experiments on electrical fluctuations", Y. Kraftmakher, American Journal of Physics 63, 932, (1995).

"A course in computer based data acquisition", W.N. Hubin, American Journal of Physics 70, 80, (2002).
"Autocorrelation of electrical noise: an undergraduate experiment", J.L Passmore, B.C. Collings, P.J. Collings, American Journal of Physics 63, 592, (1995).
"Noise reduction by signal accumulation", Y. Kraftmakher, The Physics Teacher 44, 528, (2006).
"Signal enhancement in the presence of high noise levels: the electrocardiogram", A. Thompson and A. Trolestra, The Physics Teacher 34, 418, (1996).

Supporting Literature
for the Hardware
8-bit serial in, parallel-out shift register 74164

Analog multiplexer / demultiplexers 4053

Pictorial procedure (1.6)

1. Provided apparatus
1. Provided apparatus
2. Generating a sine wave of 10 Hz with signal generator
2. Generating a sine wave of 10 Hz with signal generator
3. Connecting a signal generator to the labeled leads of DAQ for acquiring data
3. Connecting a signal generator to the labeled leads of DAQ for acquiring data
4. Setup for Nyquist Sampling Theorem
4. Setup for Nyquist Sampling Theorem
5. All function files must be in the current directory of Matlab
5. All function files must be in the current directory of Matlab
6. Front panel view of nyquist.vi file
6. Front panel view of nyquist.vi file
7. Accessing block diagram window
7. Accessing block diagram window
8. Changing sample rate in the Block diagram window
8. Changing sample rate in the Block diagram window
9. Saving data in nyq.lvm file. You can change the folder path as well
9. Saving data in nyq.lvm file. You can change the folder path as well
10. Circuitry for low pass filter
10. Circuitry for low pass filter
11. In order to change the input peak voltage to 5V, you need to use this configuration
11. In order to change the input peak voltage to 5V, you need to use this configuration
12. High pass filter with 1.3KHz cut-off frequency
12. High pass filter with 1.3KHz cut-off frequency
13. Circuitry for composite signal
13. Circuitry for composite signal
14. Setup for filtering a composite signal
14. Setup for filtering a composite signal
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