Re: Square wave excitation
Subject: Re: Square wave excitation
From: "SROYS" <SROYS-at-radiology.ab.umd.edu>
Date: Thu, 6 Apr 1995 08:38:29 EDT
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> As to a different query about other harmonics in a square wave, such
> a signal will contain the primary frequency and odd harmonics. That
> is, a 1 KHz wave will also contain 3KHz, 5KHz, 7KHz, and so on.
> Fortunately, the magnitude of each sucessive harmonic is less than
> the previous one, with the largest percentage being that of the
> primary frequency.
Actually, depending on the actual waveform (duty cycle, waveshape,
etc...), you could have a fairly complicated Fourier spectrum, not
necessarily just the odd harmonics. What I was wondering was
whether the abundance of harmonics would interfere with the tuning
process. Since you would see lots of "mini-resonances" at nominal
oscillator frequencies lower than the primary resonant frequency as the
harmonics present in the square wave come into resonance, would the
fundamental resonance still be clearly visible over and above all the
harmonic resonances? I imagine it would work, but there would just be
a lot of smaller tuning dips before you hit the big dip at the fundamental
frequency. Any practical experience with this (Chip?)?
Steven Roys (sroys-at-radiology.ab.umd.edu)