Connect the output of the sine wave signal generator to the input of the system for which you are performing the frequency response. Connect the output of the system to the input of the oscilloscope. A sine wave has a single frequency component that gives the best frequency response results.
Turn on the power to your system, the signal generator and the oscilloscope. Set the output frequency of the sine wave signal generator to its minimum setting. For example, some signal generators start from a minimum frequency of 10Hz.
Prepare a table with two columns and multiple rows. Name the first column as "Frequency of input signal" and the second as "Amplitude of output signal." Measure the amplitude of the output signal from your system on the oscilloscope. Note this value in the table against the frequency of the output signal from the signal generator.
Ramp up the frequency of the sine wave signal in small steps of 10Hz. For each step, measure the amplitude of the output signal from your system on the oscilloscope. The amplitude of the output signal being measured on the oscilloscope will start rising from a certain frequency value, remain constant over a certain range of frequencies and then start falling again.
Note the range of frequencies for which the output amplitude remained constant. This is the ideal range of frequencies at which your system will deliver optimum performance.