robismyname
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rf vs if
Can someone explain simply to me why it is much easier to perform filtering at IF rather than RF? THe way its explained to me in this book by "Dobkin" is not all that clear to me.
Dobkins says, " The task of filtering is much easier if it is performed at the IF rather than the original RF frequency. For example, a 20MHz channel represents 0.83% of the RF frequency of 2.4GHz but 5% of the 374-MHz IF, it is both plausible and true that distinguishing two frequencies 5% apart is much easier than the same exerfcise for a 1% difference."
I mean I understand how he did the math to get .83% and 5% but I dont understand how a 20MHz channel at 2.4GHz is harder to filter than a 20MHz channel at 374MHz.
Can someone explain simply to me why it is much easier to perform filtering at IF rather than RF? THe way its explained to me in this book by "Dobkin" is not all that clear to me.
Dobkins says, " The task of filtering is much easier if it is performed at the IF rather than the original RF frequency. For example, a 20MHz channel represents 0.83% of the RF frequency of 2.4GHz but 5% of the 374-MHz IF, it is both plausible and true that distinguishing two frequencies 5% apart is much easier than the same exerfcise for a 1% difference."
I mean I understand how he did the math to get .83% and 5% but I dont understand how a 20MHz channel at 2.4GHz is harder to filter than a 20MHz channel at 374MHz.