Assignment: Op-Amp Noise Theory
Directions: Please answer BOTH of the questions and respond to a minimum of two of your classmates.
Question A
Discuss methods that analog signal designers can utilize to manage noise imposed on signals.
Question B
Discuss various ways in which to measure noise in MultiSIM and in physical circuits. Include a discussion of the various instruments that are useful in noise analysis
Op-Amp Noise Theory
Answer the following questions:
1. Calculate the signal to noise ratio given RMS Noise Voltage = 10mV and RMS Signal Voltage = 1V
2. Calculate ETotalRMS given e21RMS = 4V and e22RMS = 8V
3. Calculate SNR(dB) given a noise specification of 500.5nV
4. Calculate the noise specification given SNR(dB) = 150dB
3. Include all calculations in a Word document with the title: "HW7_StudentID", with your student id substituted in the file name. Show all work for full credit.
4. Upload file "HW7_StudentID"
Op-Amp Noise Theory LAB
The purpose of this lab is to learn to use Multisim to analyze noise in op-amp circuits. Students will capture screenshots of the noise spectral density curves which will provide a visual relationship of the output noise voltage versus frequency.
1. Read the document on configuring a noise analysis in Multisim. Week 7 - Configuring Noise Analysis in Multisim.pdf
https://content.grantham.edu/at/EE332/Week_7_Configuring_Noise_Analysis_in_MultiSIM.pdf
2. Following the instructions in pdf, construct the inverting Op-Amp circuit shown in figure 1.
3. Run the simulation to measure the gain of the Op-Amp and record the values of R1 and R2 and the measured gain in the table below. (Use 5% tolerance for R1 and R2)
|
Voltage gain (Av)
|
R1 (5% tolerance)
|
R2 (5% tolerance)
|
Measured Voltage gain (Av)
|
|
1
|
1K?
|
|
|
|
5
|
1K?
|
|
|
|
10
|
1K?
|
|
|
|
12
|
1K?
|
|
|
4. For the gain of 5 in the table above, run the noise analysis to obtain the results for noise voltage for R1 and R2. (Note: You need to run this noise analysis for the circuit with the gain of 5 only)
5. Plot the noise spectrum density curve across frequency range of 100 Hz to 1 GHz. (Note: If your Multisim version does not support this option then try to download the trial version of Multisim Power Pro edition from NI website).
6. Answer the following questions:
a. Does the measured gain values match the given values? If not, explain why they are different?
b. From the noise spectral density curve, explain the effect of increasing the frequency on the noise voltage.
c. Is the voltage gain of the Op-Amp dependent on frequency? Please explain.
7. Create a new word document called "Lab7_StudentID.docx" with your GID substituted into the file name.
8. Verify all calculations from analysis and measurements from simulations. Save the results along with the table and paste the screen captures in the word document. Make sure to answer the questions.
9. Upload file "Lab7_StudentID" in Blackboard.