Passive Filter
Experiment: The frequency response characteristics of Passive Filter Networks.
Aim:
The main aim of this experiment is to investigate the response and the characteristics of different orders of Butterworth low pass filters and 5th order of Chebychev low pass filter.
Experimental Methods (including diagrams)
a) 3rd order of Butterworth low pass filter
b) 5th order of Butterworth low pass filter
c) 7th order of Butterworth low pass filter
d) 5th order of Chebychev low pass filter
1. The above figures show the circuit diagram of 3rd order of Butterworth low pass filter, 5th order of Butterworth low pass filter, 7th order of Butterworth low pass filter and 5th order of Chebychev low pass filter.
2. First, T-connecter is installed on the signal generator. One end of the T connector is connected to Channel 1 of the oscilloscope, while the other end is connected to the input of the 3rd order of Butterworth low pass filter (black test box).
3. The output of the 3rd order of Butterworth low pass filter (black test box) is connected to Channel 2 of the oscilloscope.
4. The signal generator is adjusted to give 1V peak-to-peak voltage and 1 kHz frequency.
5. The traces on Channel 1 and Channel 2 of the oscilloscope are tuned to give more accurate readings.
6. The output amplitude and the phase difference for 1 kHz frequency are measured and tabulated in Table 1. The phase difference can be computed using the formula in the figure below.
7. Step 2 to 6 is repeated by using different frequencies such as 3 kHz, 7 kHz, 10 kHz, 15 kHz, 20 kHz and 30 kHz.
8. Then, step 2 to 7 are repeated by replacing the 3rd order Butterworth low pass filter with 5th order Butterworth low pass filter, 7th order Butterworth low pass filter and 5th order Chebychev low pass filter. The readings for each low pass filter networks are tabulated in Table 2, Table 3 and Table 4 respectively.
Results
A) 3rd order of Butterworth low pass filter
Table 1
Frequency
Aim:
The main aim of this experiment is to investigate the response and the characteristics of different orders of Butterworth low pass filters and 5th order of Chebychev low pass filter.
Experimental Methods (including diagrams)
a) 3rd order of Butterworth low pass filter
b) 5th order of Butterworth low pass filter
c) 7th order of Butterworth low pass filter
d) 5th order of Chebychev low pass filter
1. The above figures show the circuit diagram of 3rd order of Butterworth low pass filter, 5th order of Butterworth low pass filter, 7th order of Butterworth low pass filter and 5th order of Chebychev low pass filter.
2. First, T-connecter is installed on the signal generator. One end of the T connector is connected to Channel 1 of the oscilloscope, while the other end is connected to the input of the 3rd order of Butterworth low pass filter (black test box).
3. The output of the 3rd order of Butterworth low pass filter (black test box) is connected to Channel 2 of the oscilloscope.
4. The signal generator is adjusted to give 1V peak-to-peak voltage and 1 kHz frequency.
5. The traces on Channel 1 and Channel 2 of the oscilloscope are tuned to give more accurate readings.
6. The output amplitude and the phase difference for 1 kHz frequency are measured and tabulated in Table 1. The phase difference can be computed using the formula in the figure below.
7. Step 2 to 6 is repeated by using different frequencies such as 3 kHz, 7 kHz, 10 kHz, 15 kHz, 20 kHz and 30 kHz.
8. Then, step 2 to 7 are repeated by replacing the 3rd order Butterworth low pass filter with 5th order Butterworth low pass filter, 7th order Butterworth low pass filter and 5th order Chebychev low pass filter. The readings for each low pass filter networks are tabulated in Table 2, Table 3 and Table 4 respectively.
Results
A) 3rd order of Butterworth low pass filter
Table 1
Frequency
References: 1. http://www.dspguide.com/ch20/1.htm 2. http://en.wikipedia.org/wiki/Butterworth_filter 3. http://en.wikipedia.org/wiki/Chebyshev_filter 4. http://www.electronics-tutorials.ws/filter/filter_8.html