- #1

CMW328i

- 8

- 1

1. Homework Statement

A receiver in a digital mobile communication system has a noise bandwidth of 200 kHz and requires that its input SNR should be at least 10 dB when the input signal is -104 dBm.

What is the maximum permitted value of the receiver noise figure?2. Homework Equations

FdB = Ps -SNR -10log (kTB)

3. The Attempt at a Solution

FdB = (-104 -30)-10 -10log (1.399x10^-23*290*200000) = 6.9 dBI can't for the life of me figure out where the -30 comes from. I even have an excerpt from the book the question came out of and it just shows the -30 in the equation without explaining where it comes from. Any ideas?

I see the input at -104, I see the bandwith, the required SNR, but no origin for -30