I want to know that what is UPPER SIDE BAND and LOWER SIDE BAND in this picture?
I have a confusion that the portion above the x axis is the USB and the portion below the x axis is LSB. I have doubt that I am thinking it in the right way.
Am I thinking it correctly ?
Am I thinking it correctly ?
No, although there is information about the USB and LSB in your graph you have not interpreted correctly.
The graph is a graph of voltage against time for an amplitude modulated signal.
If consists of a signal which is called the carrier wave, $v_{\rm c}(t) = V_{\rm c} \sin(2 \pi f_{\rm c} t)$ of frequency $f_{\rm c}$ and a message signal, $v_{\rm m}(t) = V_{\rm m} \cos\left(2\pi f_m t\right)$ of frequency $f_{\rm m}$ with $f_{\rm c}\gg f_{\rm m}$.
When these two are combined by a process called modulation the resulting voltage is of the form,
$V_{\rm am}(t) = A \sin(2\pi f_c t) + B\sin\left(2\pi \left[f_c + f_m\right] t\right) + B\sin\left(2\pi \left[f_c - f_m\right] t\right)$
which you will note is the sum of,
the carrier, $A \sin(2\pi f_c t)$, of frequency $f_{\rm c}$
the upper side band, $B\sin\left(2\pi \left[f_c + f_m\right] t\right)$, of frequency $f_{\rm c}+f_{\rm m}$
the lower side band, $B\sin\left(2\pi \left[f_c - f_m\right] t\right)$, of frequency $f_{\rm c}-f_{\rm m}$
So the side bands are the voltages above and below the carrier frequency which appear as the result of the modulation process.
From your diagram you can estimate the various frequencies as $f_{\rm c} = \frac{1}{T_{\rm c}}$ and $f_{\rm m} = \frac{1}{T_{\rm m}}$.
Often you will find the information about sidebands presented in the form of an amplitude against frequency graph as shown below.
