Signal to Noise Ratio: Questions for my multimedia and signals class

[Whoohw]

Question one

Homework Statement

x[n] = 5sin(0.22*pi)
The root mean square (RMS) value eof a sin wave is known to be A/root(2) where A is the amplitude. If the noise in a system is known to have an RMS value of 0.5, what si the signal to noise ration (in dB) of the x[n] in this syetem.

Homework Equations

RMS = A/root(2)
SNR = (Asignal/Anoise)^2
SNRdB = 10log10(SNR)

The Attempt at a Solution

Well, i figured that "A" for the RMS given (0.5) is root(2)/2

However, i do not know that which A is Asignal and which is Anoise (root(2)/2 or 5*sin(.22*pi) or just 5).

 

[Mark44]

Question one

Homework Statement

x[n] = 5sin(0.22*pi)

Shouldn't the formula above have n on the right side? Otherwise, all your values of x[n] are exactly the same.

The root mean square (RMS) value eof a sin wave is known to be A/root(2) where A is the amplitude. If the noise in a system is known to have an RMS value of 0.5, what si the signal to noise ration (in dB) of the x[n] in this syetem.

Homework Equations

RMS = A/root(2)
SNR = (Asignal/Anoise)^2
SNRdB = 10log10(SNR)

The Attempt at a Solution

Well, i figured that "A" for the RMS given (0.5) is root(2)/2

However, i do not know that which A is Asignal and which is Anoise (root(2)/2 or 5*sin(.22*pi) or just 5).

 

[Whoohw]

Thats what I keep thinking, but i that isn't what the problem has in the notation.

 

[Mark44]

Then I'd be willing to bet that it's a typo. Otherwise you don't have a sine wave. In that case x[n] is equal to about 3.1871 for all n. IOW, it's constant.