Frequency Response

Frequency Response

We often see that the bandwidth / frequency response for some audio equipment is out of human audible range. Is this really required? Human can only hear up to 20kHz, maybe more for some, but why do we need up to 100kHz of frequency response? The reason behind: music is actually made up of various fundamental frequencies that are actually more than the audible frequency range. 

Let’s take a square wave for example. It is actually made up of various sine waves of different frequencies to create the sharp 90 degC edges present on a square wave. 

We can make use of this square wave behavior to test how good the equipment frequency response or transient response is. The square wave will tell a lot of story of the device under test. Ringing, undershoot, overshoot, gradient, rounded edges, and etc will tell the quality and stability of the equipment. 

On the other hand, the old faithful sine waves can be used to measure the output power of the amplifier. 

So, if you’ve an oscilloscope, bring it out and give your equipment some tests. You can use your computer to output the sine or square waves and measure the amplifier output. You might discover some problems you encountered can be correlated to the measurement results. 

Interpreting the waveforms will be a challenge though. Different output waveform behavior at various test frequencies will tell different story. 

J&K Audio Design

19/12/2013

Click here to learn other measurement techniques.
Click here to research on other output transformer design techniques.
Click here to learn other transformer design techniques.
Click here to find out what other interesting services we offer.
Click here to find out what output transformers we have.
Click here to return to latest publication.