How to find the frequency and bandwidth of the current TV channel in the tv set-top box?

A client told us there is some missed channel on our tv box in their local area. To solve this matter, so we need to know the frequency and bandwidth of the missed channel to verify by the engineer. How do get them? At one working well tv box, press the INFO button on the remote control, then the screen will show the channel details information on the screen, you will find the frequency and bandwidth. Take a picture or write it down and send us, we will solve the miss channel problem.