Hello,

Have a look at this wiki page:
https://en.wikipedia.org/wiki/Single-sideband_modulation

Bertus

 

Hello,

Have a look at this wiki page:
https://en.wikipedia.org/wiki/Single-sideband_modulation

Bertus

Hi Bertus(sorry i make you tired), i looked now, and also someday ago, but i dont understand so good, this very simple, i just have to understand first am modulation(in spectrum analyzer),
i know you use diode like detector, after filter, but spectrum i dont understand, like i watch one video in you tube, there are for example two frequency the same, in the middle the carrie, they call upper side and lower side band, but i normal way tthey look sine wave, do you know any video in YouTube of tutorial, i watch some videos in you tube, thanx

 

Hi Bertus(sorry i make you tired), i looked now, and also someday ago, but i dont understand so good, this very simple, i just have to understand first am modulation(in spectrum analyzer),
i know you use diode like detector, after filter, but spectrum i dont understand, like i watch one video in you tube, there are for example two frequency the same, in the middle the carrie, they call upper side and lower side band, but i normal way tthey look sine wave, do you know any video in YouTube of tutorial, i watch some videos in you tube, thanx

To really understand how sidebands are generated you should go through the mathmatics of the amplitude modulation process, which is an exercise in trigonometry much more than anything to do with electronics. The result of the exercise is that you get an equation for the amplitude that has three terms, which are the original carrier frequency and the upper and lower sidebands. Once you have that it becomes clear just exactly how single sideband signals are detected by use of the BFO.

 

To really understand how sidebands are generated you should go through the mathmatics of the amplitude modulation process, which is an exercise in trigonometry much more than anything to do with electronics. The result of the exercise is that you get an equation for the amplitude that has three terms, which are the original carrier frequency and the upper and lower sidebands. Once you have that it becomes clear just exactly how single sideband signals are detected by use of the BFO.

Hi MisterBill2, ahh you mean with trgonometry and i get those 3 things, because i see also one video on YouTube, to use some math i think you get this lower carrie upper side band right? for am, ...

 

Look at the label.....of the X axis.......of an "envelope" image(amplitude).........and label of the X axis of a "spectrum" image(frequency).

See the difference?

 

Look at the label.....of the X axis.......of an "envelope" image(amplitude).........and label of the X axis of a "spectrum" image(frequency).

See the difference?

i have no oscilscope,; goodnight

 

Look at the label.....of the X axis.......of an "envelope" image(amplitude).........and label of the X axis of a "spectrum" image(frequency).

See the difference?

Hi, do you know what is the formula to put, analyzer spectrum, for example lower and carrie and upper side band? OF AM

 

Hi, i find in YouTube one video but very short 2 min,
do somebody know, (modulation index(m) = Em/Ec) ------Ec AND Em what is? i dont understand, can you show me one example please...with this modulation index(m) = Em/Ec thanks
WCt= 2*pi*fc

Here if you have time is a video on you tube

for more detail

 

Hi, i find in YouTube one video but very short 2 min,
do somebody know, (modulation index(m) = Em/Ec) ------Ec what is? i dont understand, can you show me one example please...with this modulation index(m) = Em/Ec thanks
WCt= 2*pi*fc

Here if you have time is a video on you tube

for more detail

What I suggested does not require an oscilloscope at all It creates the mathamatic expression for the magnitude of the voltage at any instant of the modulated signal. In the question about Ec and Em, Ec is the voltage of the carrier being modulated, at any particular instant And Em is the modulation voltage at any instant.

 

What I suggested does not require an oscilloscope at all It creates the mathamatic expression for the magnitude of the voltage at any instant of the modulated signal. In the question about Ec and Em, Ec is the voltage of the carrier being modulated, at any particular instant And Em is the modulation voltage at any instant.

Thanks MisterBill2, i try to calculate maybe i can find a solution, because it stay in my head, i want to do the solution, sorry i ask you to much, do you know maybe one example, i just look at Wikipedia, but there is something else formula, not like in YouTube...…...pleaseee if you have time

 

and i forget to ask Wm is this 2pim

 

This is what a ssb transmission looks like on a scope, jump to 35sec..

As i said in post# 15 it's just an AM signal but only when audio is present.

 

Thanks MisterBill2, i try to calculate maybe i can find a solution, because it stay in my head, i want to do the solution, sorry i ask you to much, do you know maybe one example, i just look at Wikipedia, but there is something else formula, not like in YouTube...…...pleaseee if you have time

The instant value of the modulated signal is equal to Am sine(Fmt)xAcsine (Fct), where Am=peak to peak amplitude of the modulation sine wave, Fmt is the angle of the modulating sine wave at the instant "t", Ac is the peak to peak amplitude of the carrier sine wave, Fc is the instant angle of the carrier sine wave at instant "t". Thus the resultant product of those terms is a sum of three terms that wind up being Fc, Fc+Fm, and Fc-Fm. My recollection of the exact derivation is probably not as great as when I had to derive it in school 50 years ago. It is the product of the values of the modulation signal and the carrier signal expressed as non-simplified sine functions. Hopefully that is an adequate explanation of the math involved.

 

This is what a ssb transmission looks like on a scope, jump to 35sec..

As i said in post# 15 it's just an AM signal but only when audio is present.

Thanks

 

The instant value of the modulated signal is equal to Am sine(Fmt)xAcsine (Fct), where Am=peak to peak amplitude of the modulation sine wave, Fmt is the angle of the modulating sine wave at the instant "t", Ac is the peak to peak amplitude of the carrier sine wave, Fc is the instant angle of the carrier sine wave at instant "t". Thus the resultant product of those terms is a sum of three terms that wind up being Fc, Fc+Fm, and Fc-Fm. My recollection of the exact derivation is probably not as great as when I had to derive it in school 50 years ago. It is the product of the values of the modulation signal and the carrier signal expressed as non-simplified sine functions. Hopefully that is an adequate explanation of the math involved.

Thank you very much...now i understand goodnight

 

Hi, i want to thank everyone, but dont be nervous with my question, because relly i read a lot of basic electronics, they dont explain such things, they hide a lot of things, but thanks the forums of electronics

 

Hello,

Have a look at page 3 of the book in the link:
https://archive.org/details/G-qrpClub1983
It will show you a product detector using a couple of transistors.

Bertus

 

Hello,

Have a look at page 3 of the book in the link:
https://archive.org/details/G-qrpClub1983
It will show you a product detector using a couple of transistors.

Bertus

Thank you very much Bertus, for a lot of help
Have a nie wekend.

 

Hello,

Have a look at page 3 of the book in the link:
https://archive.org/details/G-qrpClub1983
It will show you a product detector using a couple of transistors.

Bertus

Hello Bertus, i wil like to ask, is this receiver SSB AM? i mean what for station can pick up,

 

Hello,

Have a look at this page for the band plan:
http://www.gridgit.com/postpic/2012/12/radio-frequency-spectrum-allocation-chart_566448.jpg
http://www.extremetech.com/wp-content/uploads/2013/01/uk-spectrum-allocation-chart1.jpg

On the broadcasting band, you will find AM stations.
On the HAM/amateur radio bands, you will find the SSB stations.

Bertus