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Amplitude Modulation, Morse Code and the Fourier Series

Compromises and trade-offs must be made.

Amplitude Modulation, AM, was the first audio radio communications and broadcast method developed and is the easiest to understand. Simply put, there is a continuous sine wave of a given assigned frequency and the amplitude of that wave is changed by a signal. Usually the signal is an

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Analyzing the Frequency Spectrum of our Distortion Circuits.

The Output Wave Shape of the Diodes in the feedback Circuit.

Now that we have a way of calculating the frequency spectrum of the output from Qucs we can look at the harmonics created by our distortion circuits. The one I was most interested in was the output of the one created by diodes

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Sprouting Fuzz part II – Clamping a Signal

A clamp in the feedback circuit.

In the last post we added distortion by simply over-driving an amplifier to the point where it clipped, or squared-off the top of the waveform. It basically said…”that’s all I can do… I can’t do no more”. In this post and video I show two simple op-amp circuits

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Purposeful Distortion or It is Cool to be Square

The frequency Spectrum of a Sine Wave. (Click on the picture to expand it.)

Distortion is something that is unwanted in music reproduction systems. Those systems used to be advertised as high fidelity and claimed to reliably reproduce the sound files sent to them from phonograph records, audio tapes, etc. I have not heard

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Why both Sines and Cosines with the Fourier series?

Phase Shifting.

So far with the Fourier Series we have made some interesting waveforms but what happens in real life? Things are never as clean in real life as on paper. (Except maybe my smudged up papers.) If you think of a perfect square wave with an infinite number of odd harmonics, what would

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The Fourier Series — Part 1

A Fundamental and odd harmonics from 3 to 101

Tonight’s post is about adding multiple sine waves to create another waveform. Each of the sine waves is an positive integer (whole number) multiple of the frequency of the base sine wave. These additional frequencies are called harmonics of the the base frequency. The base

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The Mechanics of a Loudspeaker

The cross section of a Loudspeaker

In the last loudspeaker post, “The Electrical Part of a Loudspeaker” we “divorced” the mechanics from the electrical part of the speaker. But like good divorce judges we are now going to listen to the other side of the story. The picture to the left shows a cross

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An Op-Amp Datasheet part 2 – AC Values.

Non-Inverting Op-amp Amplifier

Several months ago I introduced op-amps to readers of this site with “The Non-Inverting Op-Amp Amplifier“. At that time we had only talked about D.C. Electricity. We started with an “ideal Op-Amp” and then I brought us back to reality and created a video about an op-amp datasheet. Since that time

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Bode Plots – Phase Margin and Gain Margin

Feedback Header

Generic Feedback Block Diagram

Sometimes it is very hard to not get “the horse ahead of the cart”. Very often in projects and design as well as learning multiple things must be accomplished at the same time, yet one of those laws of nature is matter can only be at one place at one

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Tone Controls, a use for the frequency response of capacitors.

Treble Cut Tone Control Circuit

“Daddy sang Bass and Momma sang Tenor”… Maybe today we don’t want to hear Daddy or maybe we only want to hear Daddy. Tone controls are a nice thing on most stereos and radios and it is a good chance to put all the theory we have been talking

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