Step 1-ADC-DAC Simulations-Lab

Step 1-ADC-DAC Simulations-Lab - ECEL 304 ECE Laboratory IV...

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ECEL 304 ECE Laboratory IV Spring 2003-04 Dr. Fontecchio Data Acquisition Project, Step 1 These instructions are based on Cadence PSD 14.2 tools PreLab Read “Memory Devices, Timing Models, and Hierarchical Blocks”, A. Motley, MicroSim Corporation, April 1997 through the “The Supporting Logic” section. Review ADC, DAC experiments from ECE-L303 Lab III Find a box to safely carry around your circuit (6” x 8” x 3” min) Discrete DAC Vcc+ V2 15Vdc 0 Vcc- D1 R2 40k D[3-0] U4A LM324 3 2 4 11 1 + - V+ V- OUT D0 R1 80k V1 15Vdc Vcc+ D3 0 S4 DSTM1 repeat 32 times 0s 0000 +1ms incr by 0001 endrepeat R5 20k R4 10k 0 R3 20k Vcc- D2 Vout Figure 1. Discrete DAC Schematic Components Used Part No Type Description PSpice Library V1, V2 VDC dc voltage source source U4A LM324 opamp opamp Rn R resistor analog DSTIM1 Stim4 4-bit digital word generator source 1. Predict and graph the expected output of the Discrete DAC summing circuit for 0 time 16 ms a. A paper sketch is sufficient, but Excel is acceptable as well 2. Create a new Cadence Capture CIS (Studio) project a. Create this project using “Analog or Mixed A/D”. Failure to do this will result in a schematic that you cannot simulate. 3. Add a schematic to your project: capture the Discrete DAC summing circuit in Capture CIS. a. Display all DSTM1 commands, as in Figure 1. 1
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b. Add your name(s) and section to the block in the lower right of your schematic 4. Set up a simulation profile and simulate your circuit for 0 time 32 ms. Graph V(D0), V(D1), V(D2), V(D3), and the output voltage vs time in Probe a. In the circuits that use the LM324 opamp (Discrete DAC and Discrete ADC) you may have a convergence error in the transient simulation. You can solve this problem by forcing PSpice to take smaller time steps in its solution. Try setting the minimum time step to about 10us in the transient simulation profile. If you still have trouble, reduce this time
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This note was uploaded on 04/05/2010 for the course ECEC 304 taught by Professor Peters during the Summer '09 term at Drexel.

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Step 1-ADC-DAC Simulations-Lab - ECEL 304 ECE Laboratory IV...

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