Below is a sample text output page for low-pass filters. At the top of the presentation is a list showing the input specifications. Listed first is the corner frequency. Next would be the stop frequency and the required attenuation for the filter unless a manual entry for the order was done as in this case. The input and output termination resistances, the filter order and the geometric configuration finish the list. Double check that all the specifications are correct. The software used the data displayed in the first half of the output. Below that is a sample output chart showing inductances in Henries and capacitances in Farads. Since low-pass filters may be either a Tee - Series or Pi - Shunt configuration, be alert to whether the element value is assigned to an inductor or a capacitor and where it is positioned in the circuit. |
In the case of a low-pass Tee - Series filter, the element at X_{1} and is an inductor and 3.542E-06 would be a 3.542 microhenry inductor. See Help - Geometry in the main menu for sample diagrams. Read the 'Geometry' section in the helps to see the exact location of each component. Finally, when entering a stop frequency and an attenuation, then letting the computer calculate the order, the attenuation will be equal to or greater than the attenuation requested. That's because the order calculation imposes a stepwise function on a continuous curve. |
Low-Pass Filter Specifications | |
Corner Frequency | 1000000 Hz |
In/Out Resistance | 50 Ohms |
Filter Order | 7 |
Filter Geometry | Tee - Series |
Filter Elements | |
Element Number | Element Value |
X1 | 3.54153E-06 Henries |
X2 | 3.96926E-09 Farads |
X3 | 1.43394E-05 Henries |
X4 | 6.36620E-09 Farads |
X4 | 1.43394E-05 Henries |
X6 | 3.96926E-09 Farads |
X7 | 3.54153E-06 Henries |