I've been struggling with this problem for several hours. I have a high IF superheterodyne receiver. The input frequency can vary from 9kHz to 3GHz. I need to calculate the minimum intermediate frequency (f_IF) if it is being used an IF filter of bandwith 1MHz. Must be kept in mind that the input frequency (f_in) is filtered using an ideal low lass filter with a cut frequency of 3GHz. Then, I must find the minimum and maximum frequency of the local oscilator (f_LO) as well as the minimum and maximum of the image frequency (f_im). Finally I must compute the range of frequencies the image rejection filter must filter, if necessary.
I have been struggling for a while. I watched a lot of videos and tried to solve it in many different ways but cannot come up with any solution.