ECET210 Week 7 iLab Complete Solution

Question: #1073

Laboratory Procedures
DeVry University
College of Engineering and Information Sciences

I.OBJECTIVES

To analyze a RC Low Pass Filter using simulation and circuit measurement.
To analyze a RC High Pass Filter using simulation and circuit measurement.
To analyze a LC Band Pass Filter using simulation and circuit measurement.

II. PARTS LIST

Equipment:

IBM PC or Compatible

Function Generator

Dual Channel Oscilloscope

Parts:

1 - 50 Ω Resistor 1 - 470 nF, 50 V Capacitor

1 - 330 Ω Resistor 4 - 47 µF, 35 V Capacitor

4 - 4.7 mH Inductor 2 - 100 µF, 25 V Capacitor

1 - 470 mH, Inductor

Software:

MultiSim 11

III. PROCEDURE

Simulation of RC Low Pass Filter |
1. Enter the circuit shown in Figure 1 in MultiSim.

Figure 1 - Low Pass Filter

Set the function generator voltage, VIn = 1 VP.

Simulate the circuit shown for various frequencies indicated in Table 1 below. Record the output voltage, VOut, for each frequency and calculate the gain using the formula: 20 log(VOut P-P / VIn P-P).

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
100			2000
200			4000
400			8000
800			10000
1000

Table 1 – Low Pass Filter Frequency Response Simulation Data

Low

Determine the voltage “Gain/Loss” in dB for the frequency response plot. Plot the simulation data of on the semi-log graph sheet below. The frequency must be on the X axis and the GaindB on the Y–axis.

What is the 3 dB cutoff frequency from the plot?

fC =___________________

Calculate the 3 dB Cutoff frequency using the formula: fC = 1/(2 π R C)

fC =___________________

Does the simulated measurement agree with the theoretical calculation?

Yes ______ No ______

B. Simulation of RC High Pass Filter

Enter the circuit shown in Figure 2 in MultiSim.

Figure 2 - High Pass Filter

Set the function generator voltage, VIn = 1 VP

Simulate the circuit shown for various frequencies indicated in Table 2 and record the output voltage and gain.

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
100			2000
200			4000
400			8000
800			10000
1000

Table 2 - Low Pass Filter Frequency Response Simulation Data

Determine the voltage “Gain/Loss” in dB for the frequency response plot. Plot the simulation data of on the semi-log graph sheet below.
What is the 3 dB cutoff frequency from the plot?

fC =___________________

Calculate the 3 dB Cutoff frequency using the formula: fC = 1/(2 π R C)

fC =___________________

Does the simulated measurement agree with the theoretical calculation?

Yes ______ No ______

C. Simulation of LC Band Pass Filter

Enter the circuit shown in Figure 3 in MultiSim.

Setup the function generator voltage, VIn = 1 VP.

Simulate the circuit shown for various frequencies indicated in Table 3 and record the output voltage and gain.

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
200			340
250			344
280			348
290			355
300			352
320			356
324			360
330

Table 3 – Band Pass Filter Frequency Response Simulation Data

Determine the voltage “Gain/Loss” in dB for the frequency response plot. Plot the simulation data of on the semi-log graph sheet below.

What are the 3 dB cutoff frequencies from the plot?

Upper fC =_____________ Low fC =_____________

The LC band pass filter is PI- Section filter which has been designed using the website:

http://www.raltron.com/cust/tools/band_pass_filters.asp

The filter has been designed to operate at a center frequency, fo of 340 Hz and a 3dB Bandwidth of 10% of fo.

Log in to the above website; feed the data of center frequency and the bandwidth desired. Verify if the design values chosen for the lab experiment are close enough.

What are the calculated 3 dB cutoff frequencies?

Upper fC =_____________ Low fC =_____________

Do the simulated measurements agree with the theoretical calculations?

Yes ______ No ______

Increase or decrease the center frequency by 5 and recalculate the element values. Note and record the new design parameters. What can you comment on the new design values when compared with the original values?

The filter can be reconfigured to a T–type using the transformation shown below:

Some useful formulas for the Constant K type band pass filter design:

Bandwidth = f2 – f1

Source for the above formulas: “HANDBOOK OF LINE COMMUNICATIONS”, A Royal Signals Pub., 1947.

Using the suggested transformation, change the original PI type filter to T-type and simulate to verify if it works as the original. Include the new filter topology below here

Did the filter work as the original? YES NO

D. Breadboard Construction of the three Filters

Build the three filters simulated above on a breadboard, one at a time

Use a Function Generator to excite the filters and check for the pass band and the cut off frequencies.
Submit a photograph of each of your working circuits (online) or have your instructor sign-off each circuit (onsite).

Laboratory Report Cover Sheet
DeVry University
College of Engineering and Information Sciences

Course Number: ECET210

Professor:

Laboratory Number: 6

Laboratory Title: Frequency Response of Low Pass, High Pass, and Band Pass Filters

Submittal Date: Click here to enter a date.

Objectives:

Results:

Conclusions:

*Team:*
	Name	Program	Signature

	Name	Program	Signature

	Name	Program	Signature

Observations/Measurements:

III. A. 3. Low Pass Filter Frequency Response:

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
100			2000
200			4000
400			8000
800			10000
1000

III. A. 4. Low Pass Filter Frequency Response:

III. A. 5. Low Pass Filter Simulated Cutoff Frequency:

fC =___________________

III. A. 6. Low Pass Filter Calculated Cutoff Frequency:

fC =___________________

III. A. 7. Low Pass Filter Simulated Versus Calculated Cutoff Frequency:

Match: Yes No

III. B. 3. High Pass Filter Frequency Response:

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
100			2000
200			4000
400			8000
800			10000
1000

III. B. 4. High Pass Filter Frequency Response:

III. B. 5. High Pass Filter Simulated Cutoff Frequency:

fC =___________________

III. B. 6. High Pass Filter Calculated Cutoff Frequency:

fC =___________________

III. B. 7. High Pass Filter Simulated Versus Calculated Cutoff Frequency:

Match: Yes No

III. C. 3. Band Pass Filter Frequency Response:

Frequency, Hz	VOut P-P	GaindB	Frequency, Hz	VOut P-P	GaindB
200			340
250			344
280			348
290			355
300			352
320			356
324			360
330

III. C. 4. Band Pass Filter Frequency Response:

III. C. 5. Band Pass Filter Simulated Cutoff Frequencies:

Upper fC =_____________ Low fC =_____________

III. C. 7. Band Pass Filter Calculated Cutoff Frequencies:

Upper fC =_____________ Low fC =_____________

III. C. 8. Band Pass Filter Simulated Versus Calculated Cutoff Frequency:

Match: Yes No

III C. 9. Modified Center Frequency:

Comment on new design values:

III. BC. 11. T-type Band Pass Filter:

Did the filter work as the original? YES NO

Questions:

Did the filters work exactly like the simulation data?

	YES / NO	Reasons for Noncompliance with Simulation
Low Pass Filter
High Pass Filter
Band Pass Filter

Grade:

Deliverable	Points Available	Points Achieved
Laboratory Cover Sheet	8
Working Circuit(s)/Program(s)	8
Observations/Measurements	6
Questions	8
Total Points	30

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