I have heard about sidebands before, but never really understood what causes them to exist. I think I finally understand that. Thanks for the very informative video!
Bill, as a Foundation Ham Radio operator studying for Intermediate and Full Licence this has been invaluable. I am very much a visual learner, so to see this is excellent. Thanks, definitely subscribed! 73s BTW I have just noticed in one of your other videos you have a Codar CR70 radio. I had one of those 50 years ago.... I loved it!
Great video as ever, Bill but it would be, perhaps a good follow-up if you could offer some explanation of how the lower SB & Carrier can be eliminated. Surely, if the side bands are a function of the carrier, then it must still exist. You can probably guess I am not "into" radios, though I do regularly use Airband for communication when flying. I guess the EASA and CAA mandated change from 25kHz frequency spacing to 8.33kHz channel spacing on Airband radios is tied up in this somehow.😁
I'm a bit confused because I thought AM was amplitude modulated. So I got lost at the point where we are combining frequencies a carrier and a modulation frequency to create a side band thats what I expected frequency modulation to be.
The image that you see (scope like) is a spectrum analyser. It shows what the power distribution of different frequenties is. It does not show modulation like a scope can. So the main spike is the carrier, and around it are lower amplitudes of other frequencies, but all still AM. Around the carrier are just other solitair frequencies created by the mixing of carrier and modulation. Nothing frequency modulation about this. Have you ever tuned an instrument with a tuning fork ? Lets say a guitar, and the snare to be tuned is slightly off. When you strike the snare and fork at the same time, you will hear 4 things: the frequency of the fork, the frequency of the snare, AND the difference between these two, AND the addition of the two, often less noticeable. When the fork is 880 Hz, and the snare is tuned as 882 Hz, you will also hear the 2 Hz difference as a wining extra sound. And there's also the total (addition) of the two basic tones, 880+882=1762 Hz, again, less noticeable than the 2 Hz. Again, nothing frequency modulation about this. In this story, the 2 Hz and the 1762 are side bands, extra wave energy left and right of the main frequency of 880 Hz. By the same principle two extra energy bands form when you take a carrier, and ADD a modulation on it. The guitar example were low frequencies, and the difference was small (2 Hz), while the addition was large (1758 Hz) compared with the ground frequency of 880 Hz. But if you use an example of 10 MHz with a modulation of 1KHz, the subtraction is 9.999.000 Hz and the addition is 10.001.000 Hz. Two extra frequencies are formed, the side bands, with the carrier in the middle, all relatively close together. When you would not use 1000 Hz modulation, but spoken word, a whole spectrum is formed as side bands close to the carrier.
This video is exactly what I was looking for. Thank you for the clear explanation.
I have heard about sidebands before, but never really understood what causes them to exist. I think I finally understand that. Thanks for the very informative video!
Great explanation. Thank you.
Excellent video Bill with great explanations - I’m studying for the Intermediate Amateur licence and your video has been extremely useful. 73
thanks for explaining
Bill, as a Foundation Ham Radio operator studying for Intermediate and Full Licence this has been invaluable. I am very much a visual learner, so to see this is excellent. Thanks, definitely subscribed! 73s BTW I have just noticed in one of your other videos you have a Codar CR70 radio. I had one of those 50 years ago.... I loved it!
Thank you and I hope you Intermediate and Full exams go well!
Maybe see you around the bands sometime...
73 de Bill
Thank u.
Great video as ever, Bill but it would be, perhaps a good follow-up if you could offer some explanation of how the lower SB & Carrier can be eliminated. Surely, if the side bands are a function of the carrier, then it must still exist. You can probably guess I am not "into" radios, though I do regularly use Airband for communication when flying. I guess the EASA and CAA mandated change from 25kHz frequency spacing to 8.33kHz channel spacing on Airband radios is tied up in this somehow.😁
Great explanation of SSB, thanks!
I'm a bit confused because I thought AM was amplitude modulated. So I got lost at the point where we are combining frequencies a carrier and a modulation frequency to create a side band thats what I expected frequency modulation to be.
The image that you see (scope like) is a spectrum analyser. It shows what the power distribution of different frequenties is. It does not show modulation like a scope can. So the main spike is the carrier, and around it are lower amplitudes of other frequencies, but all still AM. Around the carrier are just other solitair frequencies created by the mixing of carrier and modulation. Nothing frequency modulation about this.
Have you ever tuned an instrument with a tuning fork ? Lets say a guitar, and the snare to be tuned is slightly off. When you strike the snare and fork at the same time, you will hear 4 things: the frequency of the fork, the frequency of the snare, AND the difference between these two, AND the addition of the two, often less noticeable. When the fork is 880 Hz, and the snare is tuned as 882 Hz, you will also hear the 2 Hz difference as a wining extra sound. And there's also the total (addition) of the two basic tones, 880+882=1762 Hz, again, less noticeable than the 2 Hz. Again, nothing frequency modulation about this.
In this story, the 2 Hz and the 1762 are side bands, extra wave energy left and right of the main frequency of 880 Hz.
By the same principle two extra energy bands form when you take a carrier, and ADD a modulation on it. The guitar example were low frequencies, and the difference was small (2 Hz), while the addition was large (1758 Hz) compared with the ground frequency of 880 Hz. But if you use an example of 10 MHz with a modulation of 1KHz, the subtraction is 9.999.000 Hz and the addition is 10.001.000 Hz. Two extra frequencies are formed, the side bands, with the carrier in the middle, all relatively close together.
When you would not use 1000 Hz modulation, but spoken word, a whole spectrum is formed as side bands close to the carrier.
But how can you transmit just the upper sideband without the carrier and lower sideband. There is no carrier for the signal to be on the side of.