Harmonic carriers

[Martin Harris]

I am trying to understand how an harmonic carrier is properly applied
and what the effect is.

For example, if I tale a 1KHz sinewave and use it to AM a 16KHz
sinewave do I get harmonics higher than the 16KHz?

Any expert insight?

Martin Harris

 

[Hal Murray]

I am trying to understand how an harmonic carrier is properly applied
and what the effect is.

For example, if I tale a 1KHz sinewave and use it to AM a 16KHz
sinewave do I get harmonics higher than the 16KHz?

Any expert insight?

Martin Harris

I'm far from an expert, but that's pretty basic.

You will get energy at 16-1 and 16+1 KHz. No harmonics of the carrier.

You will get harmonics/splatter if you overmodulate.


http://en.wikipedia.org/wiki/Amplitude_modulation

 

[Simon S Aysdie]

I am trying to understand how an harmonic carrier is properly applied
and what the effect is.

For example, if I tale a 1KHz sinewave and use it to AM a 16KHz
sinewave do I get harmonics higher than the 16KHz?

Any expert insight?

Ideally, no. But, no system is perfectly linear. There will be some
level of harmonic response. How much is acceptable and why are the
questions.

 

[Rich Grise]

I am trying to understand how an harmonic carrier is properly applied
and what the effect is.

For example, if I tale a 1KHz sinewave and use it to AM a 16KHz
sinewave do I get harmonics higher than the 16KHz?

Any expert insight?

Not harmonics - sidebands. If your 16KHz is a pure sine wave, and your
1 KHz is a pure sine wave, and your modulator is "linear" (modulation
is a non-linear function - what I mean here is that the amplitude of the
carrier exactly follows the input), then the output will consist of
a signal at 15KHz, 16KHz, and 17KHz - the two sidebands will be half
the amplitude of the carrier (16KHz)

http://www.google.com/search?hl=en&q="amplitude+modulation"+tutorial

Hope This Helps!
Rich

 

[Chuck]

I am trying to understand how an harmonic carrier is properly applied
and what the effect is.

For example, if I tale a 1KHz sinewave and use it to AM a 16KHz
sinewave do I get harmonics higher than the 16KHz?

Any expert insight?

As has been said by the other posters,
if you start with ideal sine waves and
modulate linearly, the entire output
spectrum will consist of just three pure
sine waves.

Perfect amplitude modulation wouldn't
generate harmonics of the carrier.
However, AM is often applied to a
high-level stage or power amplifer that
is operating in some mode other than
class A with less then perfect high-pass
filtering. Consequently, that stage will
generate harmonics of the carrier
frequency. And if the carrier is being
modulated, so will the harmonics. But it
is not the modulation process that
generates the harmonics of the carrier.

Does that answer your question? If not,
maybe you can supply some additional
details.

Chuck

 

[Martin Harris]

Not harmonics - sidebands. If your 16KHz is a pure sine wave, and your
1 KHz is a pure sine wave, and your modulator is "linear" (modulation
is a non-linear function - what I mean here is that the amplitude of the
carrier exactly follows the input), then the output will consist of
a signal at 15KHz, 16KHz, and 17KHz - the two sidebands will be half
the amplitude of the carrier (16KHz)

http://www.google.com/search?hl=en&q="amplitude+modulation"+tutorial

Hope This Helps!
Rich

Due to the nature of my inquiry, it was assumed I wanted to minimize
harmonics. Understandable by convention. But actually, I would like to
_maximize_ them, especially on the higher side. IOW to obtain as many
higher above audio harmonics of the 16KHz as possible while still
using something like the sinewave AM approach originally described,
ie. not squarewaves. What would be the best way of achieiving this?

Martin Harris

 

[Phil Allison]

"Martin Harris"

Due to the nature of my inquiry, it was assumed I wanted to minimize
harmonics. Understandable by convention. But actually, I would like to
_maximize_ them, especially on the higher side. IOW to obtain as many
higher above audio harmonics of the 16KHz as possible while still
using something like the sinewave AM approach originally described,
ie. not squarewaves. What would be the best way of achieiving this?

** Physics is not game where YOU get to make up any rules you like -
fuckwit.

Harmonics are generated by distorted looking wave shapes - NOT sine waves.

A square wave has all the odd numbered harmonics included - 3rd, 5th 7 th
etc. .

Asymmetrically distorted sine waves have the even ones, 2nd 4th, 6th etc.

A mix of the two gives you the lot.

An electric guitar fuzz box does this to a sine wave input.



....... Phil

 

[Robert Baer]

I'm far from an expert, but that's pretty basic.

You will get energy at 16-1 and 16+1 KHz. No harmonics of the carrier.

You will get harmonics/splatter if you overmodulate.


http://en.wikipedia.org/wiki/Amplitude_modulation

Not quite correct; one gets the sum (16+1), the difference (16-1),and
the originals (1 and 16) KHz.

 

[Robert Baer]

As has been said by the other posters, if you start with ideal sine
waves and modulate linearly, the entire output spectrum will consist of
just three pure sine waves.

Perfect amplitude modulation wouldn't generate harmonics of the carrier.
However, AM is often applied to a high-level stage or power amplifer
that is operating in some mode other than class A with less then perfect
high-pass filtering. Consequently, that stage will generate harmonics of
the carrier frequency. And if the carrier is being modulated, so will
the harmonics. But it is not the modulation process that generates the
harmonics of the carrier.

Does that answer your question? If not, maybe you can supply some
additional details.

Chuck

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Why is it that "everyone" is ignoring *both* of the original input
frequencies?
Perhaps one needs to use a spectrum analyzer...

 

[Robert Baer]

Due to the nature of my inquiry, it was assumed I wanted to minimize
harmonics. Understandable by convention. But actually, I would like to
_maximize_ them, especially on the higher side. IOW to obtain as many
higher above audio harmonics of the 16KHz as possible while still
using something like the sinewave AM approach originally described,
ie. not squarewaves. What would be the best way of achieiving this?

Martin Harris

Use a filter tuned to 17KHz.

 

[Chuck]

Why is it that "everyone" is ignoring *both* of the original input
frequencies?
Perhaps one needs to use a spectrum analyzer...

Kind of depends on the circuit, doesn't
it, Robert? What if a DBM were used?

If the intent is to produce modulated
harmonics of a sine wave carrier, I
think the answer has been given: you
must modify (i.e., distort) the sine
wave carrier in order to produce
harmonics. For example, use a circuit
that distorts the sine wave by clipping
it. The modulator could perform this
function.

A pure sine wave simply contains no
energy other than at its own frequency.
If you're not willing to distort a sine
wave, you can't produce harmonics. Period.

Without knowing more about the
parameters of your enterprise, it is
really difficult to respond further.

Chuck

 

[Rich Grise]

Due to the nature of my inquiry, it was assumed I wanted to minimize
harmonics. Understandable by convention. But actually, I would like to
_maximize_ them, especially on the higher side. IOW to obtain as many
higher above audio harmonics of the 16KHz as possible while still
using something like the sinewave AM approach originally described,
ie. not squarewaves. What would be the best way of achieiving this?

Just generate a 16 KHz sawtooth; you'll get harmonics:
http://en.wikipedia.org/wiki/Sawtooth_wave

Or, if you want there to be harmonics of 1 KHz all around the 16 KHz
carrier, them AM it with a 1 KHz sawtooth.

Have Fun!
Rich