Chapter 3: Filtering a Signal

Complete the following steps to configure the Filter Express VI to filter the
signal using an infinite impulse response (IIR) filter.
1. Display the block diagram window and remove the wire that connects
the Result output of the Formula Express VI to the Signals input of the
Amplitude and Level Measurements Express VI.
2. Remove all broken wires that result from removing the wire.
3. Search for the Filter Express VI, shown at left, and add it to the block
diagram between the Simulate Signal2 Express VI and the Amplitude
and Level Measurements Express VI. The Configure Filter dialog
box appears.
4. In the Filter Specifications section, change the Cutoff Frequency
(Hz) to 25.
5. Click the OK button to save the configuration and close the Configure
Filter dialog box.
6. Display the front panel.
7. Click the Unfiltered Signal waveform graph indicator and press the
<Ctrl> key while you drag with the Positioning tool to create an
additional waveform graph indicator.
8. Triple-click the Unfiltered Signal 2 label above the new waveform
graph indicator and enter Filtered Signal to change the label of
the indicator. You also can change the label on the Appearance page
of the Graph Properties dialog box.
9. On the block diagram, wire the Result output of the Formula Express
VI to the Signal input of the Filter Express VI and to the Unfiltered
Signal waveform graph indicator.
10. Wire the Filtered Signal output of the Filter Express VI to the Signals
input of the Amplitude and Level Measurements Express VI and to the
input of the Filtered Signal waveform graph indicator.
11. Select File»Save.