Question

Use Multisim Simulator to design and simulate a band-pass filter whose central frequency is 15kHz and its wide bandwidth is 30kHz, with voltage gain of 50 at the central frequency. Such bard-pass filter can be realized by cascading low-pass and high-pass filters. A voltage follower stage can be inserted in-between in order to enhance the voltage coupling between the two filter stages. Moreover, the input impedance of the three cascaded stages can be enhanced making use of another voltage follower stage preceding the low-pass filter. The report of this project, should consist of the following:

1. Cover page with your name and ID.
2. Circuit schematic drawn using Multisim.
3. Design equations.
4. Simulation results obtained using Multisim showing the voltage gain magnitude as well as the voltage gain phase angle, both versus frequency on logarithmic scale.

Answer 1

To design a band-pass filter with a central frequency of 15kHz and a bandwidth of 30kHz in Multisim, one should cascade a low-pass filter with a high-pass filter and include voltage followers to enhance voltage coupling and input impedance. Design equations involve calculating capacitive and inductive reactance for the filters, aiming for a voltage gain of 50 at the central frequency. Simulation results will display voltage gain magnitude and phase angle across frequencies.

Step-by-step explanation:

To design and simulate a band-pass filter with a central frequency of 15kHz and a bandwidth of 30kHz using Multisim Simulator, one approach involves cascading a low-pass filter with a high-pass filter, including a voltage follower stage between them to improve voltage coupling. An additional voltage follower before the low-pass filter can enhance the input impedance of the cascaded stages. The design calculations for the filters are based on the desired central frequency, bandwidth, and voltage gain.

For the low-pass and high-pass filters, the cutoff frequencies must be calculated. The low-pass filter should have a cutoff frequency above 15kHz, and the high-pass filter should have a cutoff frequency below 15kHz to ensure that the passband covers the desired range of frequencies. The capacitor and inductor values for each filter need to be computed using the standard filter design equations:

• Capacitive reactance: Xc = 1/(2πfC)
• Inductive reactance: XL = 2πfL

Considering these equations, to achieve a voltage gain of 50 at the central frequency, the components of the filters must be chosen accordingly. The simulation results will demonstrate the performance of the filter with graphs showing voltage gain magnitude and phase angle versus frequency on a logarithmic scale.