1. SymbolMeaning Frequency of the Input Signal Frequency of the Lock-in Reference Frequency of the Additional Sinusoidal Input Signal (or Coherent Noise) Frequency of the Input Signal’s Amplitude Modulation Amplitude of the Input Signal Amplitude of the Additional Sinusoidal Input Signal (or Coherent Noise) Percent of the Amplitude added to the Amplitude as Amplitude Modulation ηDefined here (Increasing this value increases the intensity of this noise)here Phase Angle of the Input Signal with Respect to the Reference Signal Time Constant (the “ms” that appears in this simulation stands for milliseconds) Output of the Lock-in Amplifier in Phase with the Reference before Low-pass Filter Output of the Lock-in Amplifier out of Phase with the Reference before Low-pass Filter Output of the Lock-in Amplifier in Phase with the Reference Output of the Lock-in Amplifier out of Phase with the Reference Symbol Reference Sheet

2. Explanation of Simulation Inputs Input Signal Brief Description of “Power Spectral Density” Graph Visualization of “Input Signal” amplitude with respect to time. Visualization of “Input Signal” power spectral density with respect to frequency.

3. Explanation of Simulation Inputs Additional Sinusoidal Input Signal (e.g., due to Coherent Noise) Brief Description of “Power Spectral Density” Graph If this “Enable Sinusoidal Input” box is checked, an additional sinusoidal signal is introduced as part of the input signal. This box can be used, e.g., to introduce a third or fourth input signal. This box is NOT used in this tutorial. Visualization of “Input Signal” amplitude with respect to time. Visualization of “Input Signal” power spectral density with respect to frequency.

4. Explanation of Simulation Inputs Reference and Low-Pass Filter Settings The low-pass filter rolloff is set to 12 dB/octave for the entire tutorial τ

5. Explanation of Simulation Inputs White Noise Brief Description of White Noise η

6. Amplitude Modulation

7. Explanation of Simulation Inputs Amplitude Modulation

8. Explanation of Simulation Outputs Visualization of the amplitude of the signal “After Mixing” but before the low- pass filter Visualization of the “After Mixing” power spectral density with respect to frequency

9. Explanation of Simulation Outputs

10. Schematic Diagram of Dual Channel Lock-in Amplifier Video Tutorial For more information go to: http://www.iet.ntnu.no/courses/tfe4160/lab/lock-in_amplifier.pdfhttp://www.iet.ntnu.no/courses/tfe4160/lab/lock-in_amplifier.pdf

11. Low-pass Filter Video Explanation of Low-pass Filter

12. Low-pass Filter

14. White Noise