Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


toledo1179278911.pdf (1.05 MB)

ETD Abstract Container

Abstract Header

A Programmable Pulse Generator for In-Vitro Neurophysiologic Experiments

Licari, Frank G
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1179278911

Abstract Details

2007, Master of Science in Bioengineering, University of Toledo, Bioengineering.
The field of neuroscience has grown tremendously in the last twenty years due to advancements in instrumentation. It is now possible to electrically stimulate individual or groups of neurons, and record the results with electrodes and optical imaging techniques. Current methods to control instrumentation using waveform generation encounter many difficulties including cost, complexity, lack of customization, and multiple components to generate complex waveforms. Therefore, it would be advantageous to design a multichannel waveform generation device that can provide analog or digital signals with customizable on times, off times, delays, amplitudes, and number of cycles. A functional Direct Digital Synthesis (DDS) system was developed using a C programmed microcontroller. To begin, parameters were entered in Matlab, and microcontroller timers generated a TTL pulse using an internal oscillator to control the parameters of the waveform. An analog switch selected whether the signal entered a circuit to output a sine or square wave. If a sinusoid was selected the waveform was developed using a frequency divider and eighth order Bessel filter. The original digital or newly formed sine waves were amplitude adjusted using operational and programmable gain amplifiers. The signal was directed to the proper output channel by a set of eight analog switches addressed by a demultiplexer. This accuracy of the digital waveforms was compared with a function generator using an equal duty cycle with a range of times between 0.1ms and 1s, and the waveforms were found to be identical in timing characteristics and amplitude. The ability to generate irregular digital pulses was also tested, and the resolution was excellent over the same timing range. A sinusoid was generated using the Bessel filter and the signal was found to be clean and accurate in amplitude and frequency. The additional requirements of variable initial delay, finite number of pulses, and the ability to output from one of eight channels were also met. Future design improvements may include using a DDS IC for higher timing resolution and a programmable digital to analog converter for more accurate sine wave generation.
Scott Molitor (Advisor)
177 p.
Neurophysiology; Instrumentation; Pulse Generation; Direct Digital Synthesis; Microcontroller

Recommended Citations

Citations

  • Licari, F. G. (2007). A Programmable Pulse Generator for In-Vitro Neurophysiologic Experiments [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1179278911

    APA Style (7th edition)

  • Licari, Frank. A Programmable Pulse Generator for In-Vitro Neurophysiologic Experiments. 2007. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1179278911.

    MLA Style (8th edition)

  • Licari, Frank. "A Programmable Pulse Generator for In-Vitro Neurophysiologic Experiments." Master's thesis, University of Toledo, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1179278911

    Chicago Manual of Style (17th edition)

toledo1179278911
1,869
© 2007, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.