Interference at Odd vs Even Harmonics: Is the Square Wave Really Square?

In summary, the speaker observes that in a device they are working on, the interference is seen at even harmonics instead of the expected odd harmonics of the center frequency. They question whether this is possible, and it is suggested that this could be due to the square wave not being exactly square in the real world. The speaker also notes that the harmonic structure of a pulse signal depends on the duty-cycle, and varying the pulse-width can produce different harmonics. The difference in rise and fall times is also mentioned as a factor that can lead to different harmonics.
  • #1
cyclone24
35
0
If I look at the Fourier transform of the square wave signal, the peaks are at the odd multiples. In the device that I am working on, I would expect the interference at the odd harmonics of the center frequency.

But I see the interference at even harmonics. When is this possible?

(Only if the square wave is not really square?)
 
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  • #2
cyclone24 said:
(Only if the square wave is not really square?)

Nothing is ideal in the real world.
 
  • #3
The harmonic structure of a pulse signal depends on the duty-cycle. A real 50% square wave has the odd-harmonic structure you mention. Varying the pulse-width will produce different harmonics.
 
  • #4
It turns out that the difference in rise and fall times lead to different harmonics (odd/even)...
 

1. What is interference at odd vs even harmonics?

Interference at odd vs even harmonics refers to the distortion or alteration of a waveform, specifically a square wave, due to the presence of odd or even harmonics in the signal.

2. Why is the square wave considered a fundamental waveform?

The square wave is considered a fundamental waveform because it consists of only odd harmonics, making it the simplest form of a non-sinusoidal periodic wave. It contains only the fundamental frequency and its odd multiples, making it a building block for more complex waveforms.

3. How does interference at odd vs even harmonics affect the square wave?

Interference at odd vs even harmonics can cause the square wave to become distorted, resulting in a non-ideal square shape. This is due to the addition of odd or even harmonics that alter the amplitude and shape of the original waveform.

4. Can interference at odd vs even harmonics be eliminated?

No, interference at odd vs even harmonics cannot be completely eliminated, but it can be minimized through proper circuit design and filtering techniques. However, some level of interference will always be present in any non-sinusoidal waveform.

5. Why is understanding interference at odd vs even harmonics important?

Understanding interference at odd vs even harmonics is important in signal processing and circuit design, as non-ideal waveforms can cause issues in electronic systems. It is also crucial in the study of signal analysis and the properties of different waveforms.

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