Georgia Institute of Tec hnologySc hool of Electrical and Computer EngineeringECE 4435 Op Amp Design Laboratory Fall 2003Design Project 3A Non- L in ear Low-Pass Filter Hav in g an Imbedded ClipperIn troduction.When a sharp cutoff low-pass filter is preceded by a peak clipper, the complex filter poles cancause ringing in the filter output when the clipper is activated. This can cause signal peaks at theoutput of the filter to exceed the clipper threshold level at the filter input. A proposed method foreliminating this problem is to follo w the clipper with a non-ringing Bessel filter and to precede theclipper with a filter such that when its transfer function is m ultiplied by the Bessel filter transferfunction, the overall transfer function is that of the desired sharp cutoff low-pass filter. It followsthat the signal peaks at the output of the non-linear filter can never exceed the clipper thresholdlev el at the filter input. In addition, when the clipper is not activated, the signal will be lo w-passfiltered by the sharp cutoff filter. The object of this design project is to design such a filter withan imbedded clipper.Circuit Specifications1. The circuit will hav e a signal input with an input impedance of 10 kΩ and a signal outputwith an output impedance of 100 Ω. The dc offset at the output must be less than 50 mV.2. The circuit will con tain an imbedded clipper that has symmetrical clipping thresholds of ±5V.The clipper should hav e as “hard” a clipping characteristic as possible. A possible circuit forrealizing this is to subtract the output of a center clipper from the signal and adjust the gainof the center clipper output to optimize the “hardness” of the clipping.3. The clipper is to be followed by a unit y-gain third-order Bessel low-pass filter that has a 1/√2cutoff frequency of 5kHz.4.Theclipperistobeprecededbyafilter which has a transfer function such that when it ismultiplied by the transfer function of the Bessel filter, the resulting transfer function will be aunity-gain 0.75 dB ripple third-order Chebyshev filter with a 1/√2 cutoff frequency of 5kHz.5. The circuit is to operate from ±15 V powe r supplies.6. The permissible error tolerance for the specifications is ±5%.Design Considerations.An important criterion of your design will be the correlation you can achieve between yourexperimental laboratory results, SPICE computer simulations, and your theoretical calculations.In your preliminary design, y ou can consider all operational amplifiers to be ideal. Your final designcircuit should be capable of being tuned to compensate for non-ideal characteristics occurring inop amps and other components. Keep in mind that you should be designing a circuit whic h canbe mass produced and widely utilized. Therefore, it should be easily adjusted with off-the-shelfcomponents.Comparisons should be made among the response of an ideal noise-gate circuit, the theoreti-cal circuit response as predicted by SPICE, and the experimental circuit response. In the lab, it1will be relatively easy to measure a frequency response characteristic using the laboratory equip-men t. Comparing theoretical, experimental, and SPICE transfer characteristics will be essential inc hecking the quality of your design.P ower supplies of ±15 V and +5 V are a vailable for your design.Design Schedule1. Submit for approval a preliminary “ paper design” to your lab GTA for his review on orbefore class November 12, 2003. This paper design should sho w a possible bloc k diagramwith complete circuit diagrams of each bloc k with all component values chosen. Also, pro videdesign equations and explain the thought processes behind your preliminary design. Thispreliminary design does not have to be the final design you realize for this experiment, butit should help you begin to solidify the underlying concepts and specifications. Remember,the more information that you can provide for your lab GTA, the more direction he can giveyou and the more time he can save you in the laboratory. Your “paper design" should becomplete enough so that you can begin to assemble and test your design in your laboratoryperiod on November 13.2. Utilize SPICE to theoretically verify your circuit design. Use the 741 or LF351 op-ampmacromodels that are given on page 35 of the document located on the class web page ath ttp://users.ece.gatech.edu/~mleach/ece4435/chap02.pdf. Obtain SPICE transfer character-istic plots for the output. Present this SPICE verification of your design to your lab GTA forhis certification at your regular lab period on Novem ber 20.3. Complete the laboratory evaluation of your design with a witness verification of proper designperformance during lab on December 4.4. Submit your complete report to your lab GTA before 6:00 p.m. on December 5.Design Evaluation Criteria1. Design approach, philosophy, and clarity of explanation. Follow suggestions given in the “OpAmp Design Lab Procedures and Instructions” sheet on the class web page.2. Achievement of design specifications.3. Documentationofdesignperformance.4. Design simplicity and economics. Evaluate the cost of your design according to the instruc-tions on the “Op Amp Design Lab Procedures and Instructions” sheet.5. Assume that your design is to be used in an application requiring large quan tity productionusing off-the-shelf componen ts.6. Other Components: If you are considering using some special device or component, determinethe cost and availability of a tested and guaranteed unit from a reliable vendor. With thisinformation, your laboratory GTA will determine the equivalent cost units.ECE 4435 Design Project Evaluation CriteriaPrelab Submitted on 11/12/03 5 pointsLaboratory Attendance 10 poin tsExplanationofDesignApproach&InsightIntoDesign 10pointsBlock Diagram of CircuitDerivation of Gains and/or Transfer Functions2Design of the Bessel FilterDesign of the clipperDesign of the Bessel to Chebyshev converter filterInput Impedance ConsiderationsOutput Impedance ConsiderationsResults & Presentation of SPICE Simulations 5 points“Signed Off” in Lab during the second lab periodSPICE Simulation of Final Overall CircuitPresentationEconomics & Cost Analysis 5 pointsJustify Design ChoicesTotal Component CostPresentation of Experimen tal Results 5 poin tsComplete Documentation of Results Verified in LabComparison of Theoretical, SPICE, and Experimental Results (In Tabular Form with %Errors)Explanation of ResultsExplanation of