作者supsymmetry (supsymmetry)
看板comm_and_RF
标题[问题] aquestion of bit errors per day
时间Wed Jan 10 15:28:21 2007
A continuously operating coherent bpsk system makes errors at the average ra
te of 100 errors per day. The data rate is 1000bits/s. The single-sided nois
e powere spectral density is N_0=10^{-10}W/Hz
a) If the system is ergodic,what's the average bit error probability?
b) If the value of received average signal power is adjusted to be 10^{-6}W,
will this received power be adequate to maintain the error probability foun
d in part a)?
Solution:
a) P_{e}=100bits/day/(24*3600s/day*1000bits/s)~=1.1*10^{-6}
b) I guess the answer is no. But I don't exactly know how to compute the bit
errors per day given the average signal power.
The follows is my solution, please help to check:
Set p_{b}=10^{-6}Watt which is the average signal power,Num_{e} is the numbe
r of bit errors per day.
Num_{e}=N_0/(P_{e}*p{b})=10^{-10}/(1.1*10^{-6}*10^{-6})=100/1.1/day
I wonder the solution just coincides with the correct answer by accident and I
can't tell its physical explanation. Coz the formula doesn't include a time
factor.
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※ 编辑: supsymmetry 来自: 220.172.19.64 (01/10 15:30)