Test and measure AM and FM modulators

[walters]

A AM and FM modulators mix or superimpose the carrier signal and un-modulated signal inside the chip how does it do this please?

How does it take a carrier frequency and un-modulated audio signal and mix or superimpose them inside the chip?

what are AM and FM modulators are they mixers?

Is a multiplexer a mixer?

 

[audioguru]

AM. The amplitude of the carrier is changed by the modulating signal.
FM. The frequency of the carrier is changed by the modulating signal.
A mixer won't do that.

A multiplexer can take a piece of some signals and give an output with the pieces in sequence.
A mixer won't do that.

What does Google say about how radios work?
Try www.howstuffworks.com.

 

[walters]

Thanks for the information

How do u "combine" the carrier signal with the un-modulated?

Which chip combines the carrier signal with the un-modulated signal?
whats the chips name?

How does the chip combine inside the chip the carrier signal with the un-modulated signal to output a "modulated signal"?

 

[akg]

Thanks for the information

How do u "combine" the carrier signal with the un-modulated?

Which chip combines the carrier signal with the un-modulated signal?
whats the chips name?

How does the chip combine inside the chip the carrier signal with the un-modulated signal to output a "modulated signal"?

it's called a modulator
u may or may not need a chip
http://en.wikipedia.org/wiki/Modulator
**broken link removed**
http://www.discovercircuits.com/M/modulators.htm

 

[walters]

But how do AM and FM modulators work inside the chip? how do they combine the carrier frequency or signal with the un-modulated signal?


If i don't use a modulator how does the carrier signal get combined with the un-modulated signal? what happens when not using a modulator?

If u "bypass" the modulator the carrier signal will not comine or superimpose?

 

[walters]

A stereo multiplexer chip takes a stereo audio waveform input signal and converters it into a data carrier signal?

A demultipler chip takes the data carrier signal and converts it back to a stereo audio signal

 

[walters]

How do i change the Modulated Envelope?

The modulator chip combines the carrier frequency (which is variable)
with the un-modulated audio input signal.

Inside the modulator chip there is a modulation Envelope how do i adjust the envelope shape?

On the output of the modulator chip is the "modulation signal" ( which is the carrier frequency combined with the un-modulated signal). The "moduation envelope" i want to vary do i can change the "modulation envelope" how can i do this please?

There is a "AM modulation envelope"
There is a "FM modulation envelope"

I want to change the AM modulation envelope and the FM modulation envelope how can i do this please?

 

[akg]

If i don't use a modulator how does the carrier signal get combined with the un-modulated signal? what happens when not using a modulator?
If u "bypass" the modulator the carrier signal will not comine or superimpose?

U need Glue to make a single piece of wood from two. The 'glue' is the 'modulator' . If u bypass it......

 

[walters]

yea i know the glue is the modulator but how does the modulator work inside the modulator chip?

Which Moculator chip can have a variable "modulation envelope" parameter?

 

[walters]

What are sidebands?
Either of the two bands of frequencies, one just above and one just below a carrier frequency, that result from modulation of a carrier wave.


So are sidebands from the carrier frequency or the non-modulation frequency?

where is the sidebands at?

Are sidebands modulating the carrier frequency?


What does the carrier frequency do?
"carry" data

What kind of "Data" does carrier frequency ?


Whats a suppressed-carrier modulation?

 

[akg]

Which Moculator chip can have a variable "modulation envelope" parameter?

u mean depth of modulation..?

 

[akg]

What are sidebands?
Either of the two bands of frequencies, one just above and one just below a carrier frequency, that result from modulation of a carrier wave.

if Fc is the freq of carrier and Fm is the freq of data signal(eg:sine)
then Fc+Fm and Fc-Fm are the sidebands

U need to study communication priciples , theory etc . to understand all these.

 

[walters]

Thanks for the information

Does the modulator chips have a "variable" depth of modulation parameter trim pot?

whats the difference between "depth of modulation" VS modulation envelopes?

I'm looking for a modulator chip that has "trim pots" for depth of modulation and modulation enveloples?

 

[audioguru]

A variable depth of modulation control is just a volume control of the amount of modulation.

 

[walters]

"variable depth of modulation control is just a volume control of the amount of modulation"

a Volume pot on the un-modulated signal "before" the modulator chip?
(or does the modulator chip have a "trim pot" to adjust the depth of modulation inside the modulators chip?

How do i have a variable 0-100% "depth of modulation" ?


How do i adjust the Envelope of the modulation to change the Envelope slopes and curves of the modulators modulation waveform?

 

[walters]

how do i make the modulator chip "unbalanced"?

When i put my probe down on the "output" of a modulator chip i see alot of vertical lines like its slicing the waveform into pieces what are theses vertical lines called please?

The envelope of modulation is like a bubble around the waveform how does the modulator chip make this envelope

Look how the envelope of modulation changes the bubble shape:
**broken link removed**

**broken link removed**

Whats the E symbol and chip called? is the E symbol another modulator?

 

[audioguru]

The modulating signal is the audio that modulates the RF carrier. An ordinary volume control adjusts the amount of audio that feeds the modulator, therefore changes the depth of modulation.
Nobody makes a "modulation chip". You make your own modulator circuit.

Turn the modulation volume control down and the modulation index is zero. Turn it up and guess how much the modulation index will be.

The amount and type of modulation changes the envelope of the modulated carrier. With AM modulation the envelope changes its amplitude by the modulating audio. With FM modulation the envelope doesn't change.
If you want to change the AM envelope slopes and curves of the modulator's modulation waveform then feed it audio that does it. A sinewave makes a mirrored sinewave envelope. A triangle wave makes a mirrored triangle wave (looks like diamonds) envelope. Guess what the envelope looks like with a squarewave audio signal.

 

[walters]

Thanks alot so much for the information

What is this envelope bubble called?

the modulator chip in side that makes the envelope bubble is the sideband f1-f2 "not" f1+f2

F1-F2= makes this envelope bubble inside the modulators chip but how ?

 

[audioguru]

how do i make the modulator chip "unbalanced"?

What is unbalanced? The top part and the bottom part?

When i put my probe down on the "output" of a modulator chip i see alot of vertical lines like its slicing the waveform into pieces what are theses vertical lines called please?

The carrier frequency.

The envelope of modulation is like a bubble around the waveform how does the modulator chip make this envelope

By Amplitude Modulation of the carrier.

Whats the E symbol and chip called? is the E symbol another modulator?

It isn't E, it is the Greek letter Omega. It adds the two modulated carriers together. It is an RF summing circuit, not a chip.
Learn about quadrature modulation and balanced modulators.

 

[walters]

how do i make the modulator chip "unbalanced"?

What is unbalanced? The top part and the bottom part?

Yes how do u make the sidebands "unbalanced" the upper and lower parts?

Or the modulator chip is self how to make it unbalanced?