1. An Interesting Filter Fall 2003 ECPE 141 – Advance Circuits Author: Henry Pham

2. Objectives Design Specs and Transfer Function Circuit Simulations & Results Interesting Facts References

3. Design Specs & Transfer Function 2 nd Order Salleen- Key HPF 2 nd Order Salleen- Key LPF Inverting Amplifier

4. Circuit Schematic (Dorf SP16.5)

5. Realized Circuit Real Circuit Cleaned Up for Reimplementation

6. Circuit Simulations & Results Measured Gain and Spice Gain Measured and Spice dB Gain

7. Continue Measured and Spice Phase Angle

8. Continue Transient Response of the Interesting Filter

9. What happens to the circuit when you replace one capacitor?

10. Capacitor Change Simulations Frequency Response Transient Response

11. Why is it an Interesting Filter? Lower Stop Frequency at 16Hz 20db/decade Upper Stop Frequency at 320Hz 20db/decade Roll-Off at 310kHz 75db/decade

12. More Interesting Facts Resistors connecting the entire circuit directly affect gain.

13. References 1. Al – Hewlett Packard, Design Engineer 2. Joe Carr’s Radio Tech Notes. Filter, Attenuator, Preamplifier, Preselector - - or Barefoot. http://www.dxing.com/tnotes/tnote07.pdf http://www.dxing.com/tnotes/tnote07.pdf 3. Dorf & Svoboda. Introduction to Electrical Circuits Fellow Students and Dr. Khoie