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Yi Yao Oscilloscope. Yi Yao Projects Oscilloscope. Project started on 2. Altera Quartus License Generator SoftwareSolutions Search LDO Linear Regulators Terasic DE10Nano Kit. Sep 26th 2017 The Terasic DE10Nano is a development kit based on an Intel Cyclone V SoC which. Xilinxs ISE or the free ISE WebPACK Alteras Quartus II or the free WebLite Edition Designentry VHDL, Verilog, ABEL, Schematic, EDIF VHDL, Verilog. Verilog1995 and 2001 limit reg variables to behavioral statements such as RTL code. SystemVerilog extends the reg type so it can be driven by a single driver such. Project completed on 2. First of all, many thanks to Professor Iravani for teaching us the analysis of linear systems, Professor Wang for her patient tour of digital logic and Verilog. To all the lab TAs for tips on debugging circuits and practical insights. To Mr. Rundle for introducing me to CC and of course, Mr. Altera Quartus License Generator' title='Altera Quartus License Generator' />Bemmel for showing me the door. La Blue Girl Rapidshare'>La Blue Girl Rapidshare. Motivation. Not everyday does one feel the urge to build an oscilloscope. There were many motivating factors. My experience with oscilloscopes began with an old analog machine in the bowling alley of my high school, Marc Garneau CI. I just remember how tedious it was to get the thing to show a trace. And then to trigger properly. Upon comparing the results with known values, I realised that the oscilloscope was off vertically and horizontally i. And the probes were so oxidized. One couldnt quite understand why it wouldnt work. So many pains. But there was excitement when the darn thing finally worked and you could see the Lissajous curves or the capacitor charging and discharging. And then, there was these awesome shiny new digital oscilloscopes in the electrical engineering and physics labs at University of Toronto. They even had an auto set function. I mean, how cool is that You didnt have to fiddle with the knobs anymore, it just worked. I immediately knew what I wanted for Christmas or my birthday. Looking in the Allied Electronics and Newark in One catalogues, I found out that that was out of question. The Agilent 5. 46. D 1. 00. MHz mixed signal scope. Such a beauty, no Starting from 5. USD. So my natural instinct is to build one if I cant afford one. And thats what I spent my Winter holidays doing. Requirement Specs. These were the preliminary requirements that I set out to fulfill 1 channel or 2 channels with common ground. It seemed hard to have 2 channels working in electrical isolation. Digital. I dont have a CRT or know how to control one. Communicate to a computer Palm Pilot via RS2. For easy debugging and display, a computer is fast and easy to program. Also allows for future interface with Palm Pilots and easy porting to other systems. Accuracy of 1m. V5. V to 5. V input range. Ampilifcation circuit have relatively high cut off frequency 4. KHz suggested. Relatively high compared to the 4k. Hz nyquist frequency of 8kspsExplanation. For those of you who are new to this stuff, heres what the requirement specs mean. The number of channels which an oscilloscope has is the number of signals which it can be viewed at the same time. I hope you know what digital and analog means. For the purpose of this project, digital signals can be communicated with computers while analog signals cant. RS2. 32 is the name given to your serial port. Marketing Metrics Digital Handbook. At the back of your computer, theres many ports where you can plug things into. The RS2. 32 port has 9 pins and looks like RS2. At the heart of most digital oscilloscopes is a device usually a chip of some sort which converts analog voltage levels to digital signals. This chip is called an analog to digital converter ADC. If this happens very quickly and the computer keeps track of voltage over time, a plot can be drawn, hence the principal of a digtal oscilloscope. How quickly the chip is able to make these conversions is called the sampling frequency. It is given in units of ksps kilo samples per second or Msps mega samples per second. And if you know the sampling frequency to be f, the highest frequency sine wave it can detect is f2. This is known as the nyquist frequency. Any higher than that and all youll get erroneous results and an effect known as aliasing click here for details. For my case, I chose ADC0. Supremetroncis. This chip is guarenteed to work at 8ksps. And hence, the nyquist frequency is 4k. Hz. That means, the fastest sine wave I can see with chip is 4k. Hz before bad things start happening. Most oscilloscopes have some analog circuit which will amplify and shift the trace before it is sampled by the ADC. By shifting the signal before amplifying it gives better accuracy in many cases avoid saturation with amplifiers. As with all analog circuits, they will work only within a range of frequencies. After a specific frequency, the cut off frequency, the output voltage level is less than 7. It would be preferrable for this frequency to be much higher than the nyquist frequency of the ADC. So, now that we know what were looking for, heres the design. Design. While I had some knowledge of electronics hardware, I still do not understand all components fully. It is very different to sketch an opamp circuit on paper than it is to choose the correct components and lay it out to minimize noise. So, theres bound to be oversights where a resistor value was too low or the components were not well chosen, etc. Hence the difference between physics where it supposed to work and engineering were good approximations and correct components are key. Im still learning so please contact me with comments and suggestions. The design of this oscilloscope was simple. It is summarized with the following diagram. Flow diagram for the digital oscilloscope. Vertical Shift and Amplifier. Bonnie And Clyde 2013 Part One. The purpose of these modules is to condition the signal appropriately for the ADC to read. The ADC can convert voltages within the range of 0 to 5. V. By setting the vertical offset and amplification, one can zoom into a portion of the signal one is interested in. A suitable equation relating the input voltage Vin, vertical offset Vs, amplification A and the output voltage to the ADC Vadc can be which would allow for the maximum of 1. V input range A1, Vs0, Vin 5. V to 5. V. Also, this scope must have accuracy of 1m. V. The typical screen size on a Palm Pilot is 1. X1. 60 pixels. Hence a 1. X1. 00 pixel window with 1. X1. 0 grid would be suitable for showing the trace which leaves enough space to display system information. This means, the smallest range this oscilloscope should be able to capture is within a 0. V 1. 00px X 1m. Vpx range. It would also be nice to have variable gain inbetween these two ranges as well. The following table lists the magnifications posible. Circuit parameters. Volts per Divm. VMeasurable WindowVAmplification NeededXFeedback Resistor see circuit, RfkMultiplexer Index. With the design equation in mind, an opamp circuit was created to perform the desired amplification. This was done by cascading a series of buffers, differential amplifiers and summing amplifiers. The result was Click on image for higher resolution schematic. Originally, 1. 0k resistors were chosen for most of the circuit since resistors with values in multiples of 1. This would be useful for the variable gain circuit. However, Supremetronics ran out of them and I was out of luck. So 2. 0k were used instead. I salvaged a few 1. Due to the sensitive nature of this project, all resistors had 1 tolerance. The opamp chosen was the LF3. It has high bandwidth of 4. MHz, input impedance of 1. Each package contained 4 opamps which saved space and came at an economic price. Im sure that was not the best reason to pick this opamp, but it still worked. The variable gain amplifier must be able to accomodate 7 distinct amplification levels. This meant, Rf could be 7 independant values. This was accomplished by using a 4. IC which was not shown on the schematic. Based on the input to the IC, Rf could be configured to choose any of the 1.