Lab 1 - EE420L
Authored
by Marco Muņiz,
Email: munizm1@unlv.nevada.edu
1/28/19
Prelab:
- Learn how to edit webpages
- Review Lab 1 prior to lab
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Lab Description:
For this first lab simulate, and verify the
simulation results with experimental measurements, the circuits seen in
Figs. 1.21, 1.22, and 1.24 (use a 1uF cap in place of the 1pF cap) of
the book. Your results should be similar to, but more complete than,
the simulation results seen on pages 17 - 23. In your report, and for
each circuit, show the
- Circuit schematic showing values and simulation parameters (snip the image from LTspice).
- Hand calculations to detail the circuit's operation
- Simulation results using LTspice verifying hand calculations.
- Scope Waverforms verifying simulation results and hand calculations.
- Comments on any differences or further potential testing that may be useful (don't just give the results, discuss them).
For the AC response seen in Fig. 1.23 generate a table showing some
representative measurement results (frequency, magnitude, and phase).
If you would like to include a plot of this measured data then using a
plotting program, such as Excel, add the image to your report.
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Main Lab:
Part 1:
For the first part of the lab, we will be analyzing different RC Circuits from the CMOSedu textbook.
Fig. 1.21 Analysis
Circuit Schematic along with Hand calculations for given RC circuit.
(Fig 1.21 Schematic)
(Hand
Calculations for Fig. 1.21 @ 200Hz)
From
the Phase Calculations, we can see that the sign is negative. This
would indicate that the output is lagging the Input, which is what we
would expect in a RC circuit.
Simulation Results:
(Transient Analysis of Fig. 1.21 @ 200Hz)
In
the above plot, we can see how close our simulation results compare to
our calculated results. The voltages are quite close with only a slight
change of 15us in the delay time.
(AC Sweep of
Fig. 1.21 @ .ac 100 1 100k)
In
the AC Sweep plot for Fig. 1.21, we see that slightly above 200 Hz, we
begin to see a drop of about 20dB per decade with the phase going down
to -45 degrees which signifies the output is lagging the input.
Experimental Results:
(Oscilloscope results for Fig. 1.21 @ 200Hz)
In
the Oscilloscope plots above, we can see the measured values in the
bottom right menu. In the output signal, we see a voltage output of
approximately 640mV, a phase of -48.9 degrees, and a Time delay of
712us. These values are within 10% of our calculated and simulated
values.
In
the spreadsheet on the left, we have the oscilloscope values collected
for the Circuit in Fig. 1.21. For the really high frequencys, the
oscilloscope was having some issues taking measurements. Because of
this, the values of 100k Hz we derived from theoretical values of what
would occur in the RC circuit. On the right, we have a comparison of
all values collected for this circuit. V(dB) = 20*log(|Vout/Vin|)
Fig. 1.22 Analysis
(Fig. 1.22 Schematic)
(Hand Calculations for Fig. 1.22 @ 200Hz)
As in the calculations for Fig. 1.21, we can see that the phase is
negative which indicates that the output is still lagging the
input.
Simulation Results:
(Transient Analysis of Fig. 1.22 @ 200Hz)
In the above simulation plot, we can see how close our values are to the theoretical values with Vout = 695mV and a Td = 93 us.
(AC Sweep of Fig. 1.22 @ .ac 100 1 100k)
In
the AC Sweep for Fig. 1.22, we see a significant difference to the
results in Fig. 1.21. Particularly, the phase in this circuit is
approximately zero for both Very low and Very high Frequencies. Also,
the overall voltage magnitude only drops to about 4 dB.
Experimental Results:
(Oscilloscope results for Fig. 1.22 @ 200Hz)
In
the above Oscilloscope results, we can see the experimental values of
the circuit in Fig. 1.22. Overall, the values we see are close to what
we would expect with a Output Magnitude of 720mV and a Phase of -6.3
degrees. However, we did see some bigger changes in our Time delay. We
recorded a delay of 128us which was a decent amount off from the 94us
calculated. We attributed this to user error considering it was our
first time using these newer oscilloscopes.
In
the above spreadsheet, we have the values of our various parts listed.
Overall, the output magnitude values are fairly close but the biggest
issue we had was with the Time Delay calculations, in which we see a
difference of about 35 us.
Fig. 1.24 Analysis :
Td = 0.7*RC = 0.7 * 1k * 1u = 700us
Tr = 2.2*RC = 2.2 * 1k * 1u = 2.2ms
Simulation Results:
(Fig. 1.24 Time Delay Results)
We recorded the delay time as the amount of time it took the output to reach its 50% mark.
(Fig. 1.24 Rise Time Results)
We recorded the rise time as the amount of time it takes to go from 10% to 90% of the output signal.
In both simulation results, we see very little disparity between our calculated and simulated results.
Experimental Results:
In
the spreadsheet above, we all recorded values for Fig. 1.24. Overall,
we see not much variation in the results. The Experimental results were
slightly off but we attribute this to user error with oscilloscopes we
are not familiar with.
All work is backed up onto my student Google Drive.
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