Lab 5. Active Low Pass Filters

Laboratory Work

This lab will focus on the basic thing in active circuit designs, including how to create

schematics in ADS. The video includes information on ADS commands, icons, components,

pallets, libraries, measurement equations, variables, wire labels, templates and more.

Building Active Low Pass Filters in ADS:

Step 1: Create a blank schematic and save into a workspace (refer to previous exercise about

how to do this)

Step 2: Click the Library Browser on the top-left corner.

Step 3: Select the library “ads_behavioral —> System Amps & Mixers” or search all libraries

with “OpAmp”, and drag the device “OpAmp” to the design environment.

Step 4: Build the following circuit with the same components values and pay special attention

to the marked components values:

Step 5: Select Simulation-AC and drag “AC” to the design environment.

Step 6: Add two names of “Vin” and “Vout” Using “NAME” to the designed circuit.

Step 7: After running the simulation, there is a result window turned up automatically. Select

the “Equation” from the left-hand side Palette and enter equation as below instructions. Then,

Select the “Rectangular Plot” and chose the entered equation “Gain”:

Step 8: Plot the curve “Gain” and attach the screen shot.(30 Marks)

Please answer the questions below:

What is the value of “Gain” when frequency equals 0 Hz? why? (10 Marks)

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What is the variation trend of Gain with frequency? try to explain why. (10 Marks)

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A. Please build another active lowpass filter as shown below and use the above learned

techniques to view the curve and draw the results below:

Plot the Gain and attach the screen shot below. (30 Marks)

Please answer the questions below:

Try to state the differences between these two active low-pass filters. (20 Marks)

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