Part C. Analog RC filter analysis using the Bode Analyzer: A bode plot defines the frequency characteristics of a given circuit. Magnitude response is plotted as circuit gain in decibels as

a function of log frequency. Phase response is plotted as the phase difference between input and output signals on a linear scale as a function of log frequency. NI ELVIS has a bode analyzer SFP which facilitates automatic bode plot generation of a given circuit. Complete the following steps to obtain the Magnitude and Phase response of the RC filter: 1. Retain the circuit configuration from the previous section. Note that the circuit should be setup as shown in figure 11. 2. Ensure that the connections are correct and switch the prototype board power to ON position. 3. From the NI ELVIS instrument Launcher, select Bode Analyzer. The initial Bode Analyzer SFP should appear as shown in figure 17. 4. Bode analyzer controls the input signal to the circuit from the FGEN ports. The output signal to be analyzed should be connected to Analog Channel 0 (between AI0+/AI0-). The input signal should also be connected to Analog channel 1 (between AII+/AII-). 5. Bode analyzer provides the flexibility to automatically scan the input signal frequency over a range specified by Start/Stop frequency values. The incremental value used during this frequency scan can also be set to a specific value. All these controls can be seen in figure 18. 6. For analyzing the RC low pass filter, let's make the following settings on the Bode analyzer SFP. 7. 8. Start frequency to 10 Hz. Stop frequency to 100 KHz. Steps to 20 per decade (Higher the number of steps, greater the number of points for the measurement accuracy). Display section, set Y-scale to Auto. Click on RUN. Once the analysis is complete, the output should appear as shown in figure 19. In the figure 18, cursor has been placed to measure the -3dB frequency. This can be achieved by clicking on the Cursors button to "ON" and dragging the cursor using the left mouse button on the plot to the desired position. The cursor can also be shifted to the desired position using the two diamond shaped buttons in the Cursor Position/nBode Analyzer - NI ELVISmx Phase (des) LabVIEW 0.8- 0.6 0.2 0.0- -0.4 -0.6- 0.8 -LO 25.0 20.0 15.0 Phase (deg) 10.0 5.0 0.0 -5.0 -10.0 -15.0 Frequency (t) 0.00 (ap) Bode Analyzer - NI ELVISmx LabVIEW 0.0- -2.5 -5.0 -10.0- -12.5- -15.0- -17.5 -22.5- 0.0- -30.0 -20.0 80.0 Connections: SCOPE CHO-FGEN SCOPE CH 1 - Signal 10 1000 Frequency (Hz) 1000 Frequency (H₂) Phase (deg) 0.00 Gain 0.00 Gain (8) Inf 1000 Frequency (tr) Connections: AI 1-FGEN ATO-Signal 1000 Frequency) Frequency (Hz) 5623.33 Phase (deg) 43.83 Gain 0.72 10000 10000 10000 10000 Gain (d) -2.89 100000 Measurement Settings Stimulus Channel SCOPE CHO 100000 Start Frequency 100.00ⒸH Stop Frequency Fig.18. Uninitialized NI ELVIS Bode Analyzer window. 10.00kr Steps Peak Amplitude 2.00 5 per decade) Graph Settings Mapping Logarithmic Cursor Settings Cursors On Cursor (Real) Instrument Control Device Devi (NI ELVIS II+) Start Frequency 10.00ⒸH Stepe Response Channel SCOPE CH 1 Stop Frequency 300.00k Stop Print Log Help Measurement Settings Stimulus Channel Response Channel AL 1 ATO Peak Amplitude 2.00 Op-Amp Signal Polarity Normal Graph Settings Mapping Logarithmic ✔Autoscale Position Left◆◆ Right 20(per decade) Cursors On Cursor (Real) Instrument Control Op-Amp Signal Polarity Normal Autoscale Position Left →→ Right Dev10 ELVIS 114) Run Stop Print Log Help B