# Homework Help: Find Eb/No : signal to noise ratio

1. Sep 4, 2010

### bos1234

1. The problem statement, all variables and given/known data
If the received signal level for a particular digital system is -151dBw and the receiver system effective noise temperatyre is 1500K, what is E_b/N_o for a link transmitting 2400bps?

solution says:
(Eb/N0) = –151 dBW – 10 log 2400 – 10 log 1500 + 228.6 dBW = 12 dBW

My attempt:
Im trying to use C=Blog_2(1+SNR) and N=kTB
But I have 3 variables and only 2 equations. B's will be cancelled but N and SNR(E_b/N_o) are unknown

2. Feb 23, 2018

### Rajeswari Rajasingh

Thermal noise in Watt= kTb
Thermal noise in dBW(N)=10logk +10logT +10logb
N=-228.6+10log1500+10log2400=-163.037dBW
Eb/N0=S/kTb
(Eb/No)dB=S dBW -N dBW=-151 -(-163.037)
=12.03 dBW

3. Feb 23, 2018

### Staff: Mentor

Welcome to the PF.

The rules do not allow us to provide solutions to homework problems. We can give hints, ask questions, find mistakes, etc. But the student must do the bulk of the work on their homework assignments. Please keep that in mind in your future posts here.

But since this thread is about 8 years old, and this student likely has their PhD by now, I'll allow your post to remain.