Efficiency of DSBFC Modulator vs. Balanced Modulator: A Comparison

[rude man]

Ok, thanks so for the SNR I would essentially have the power above with a (4R) as the denominator of the numerator...and 2fIFNo as the denominator?

For the SNR your numerator is (Ec^2/4R)(G_T^2)C and the denominator is 2No*f_IF.

 

[rude man]

I have:
SNR=\frac{\frac{E_c^2*1/4*(m^2+2)*G_T^2}{4R_T} *C))}{2f_{IF} N_0}
?

No, you can't count the carrier power as signal power.

 

[Fisher92]

Ok, first mistake is not setting m to 1 - then I need to remove the carrier power. I am going on an eqn I found in the text, Esf=mEc/2 sp Pinfo=(Ec^2/4)/R - Is that how you derived the same?

 

[Fisher92]

SNR=\frac{\frac{E_c^2 G_T^2}{4R_T}*C}{2f_{IF}*N_0}

If the total power amplification through the receiver stages is GR find the output power of the receiver.
As we've established the power at the input is the information or sidebands power
P_{out}=\frac{E_c^2 G_T^2*G_R^2}{4R_T}*C
Assuming the gains are voltage, & ill make a comment on that

e. If the noise power at the output is identical to the noise power at the input of the receiver, find the NF for the receiver

NF = input SNR/output SNR

If the above, power output is correct, this is easy enough - algebra may simplify but my calculator will figure that out

?

Thanks

 

[rude man]

SNR=\frac{\frac{E_c^2 G_T^2}{4R_T}*C}{2f_{IF}*N_0}

If the total power amplification through the receiver stages is GR find the output power of the receiver.
As we've established the power at the input is the information or sidebands power
P_{out}=\frac{E_c^2 G_T^2*G_R^2}{4R_T}*C
Assuming the gains are voltage, & ill make a comment on that

I think that's good.

e. If the noise power at the output is identical to the noise power at the input of the receiver, find the NF for the receiver

NF = input SNR/output SNR

If the above, power output is correct, this is easy enough - algebra may simplify but my calculator will figure that out

?

Thanks

Shouldn't be too hard! And I speak euphemistically! Let me know what you came up with?

 

[Fisher92]

I'm in time zone GMT-7 (Arizona USA) all year. (No dst).

-Gotta love the internet!

For part d, the noise figure, I ended up getting N_0=\frac{1}{G_R^2}

Probably not right (doesn't make much sense I don't think) but its only one part of a question.

Thanks for all your help with these two questions RM!

 

[rude man]

-Gotta love the internet!

For part d, the noise figure, I ended up getting N_0=\frac{1}{G_R^2}

Probably not right (doesn't make much sense I don't think) but its only one part of a question.

Thanks for all your help with these two questions RM!

No, the NF = 0 since the receiver itself does not introduce any noise of its own.

Let me know what if any feedback you get from your instructor for any part or parts of this problem? Especially about the power at the receiver input.

 

[Fisher92]

Thanks, will do - the uni has a two week turn around for assignment marking.

 

[rude man]

Thanks, will do - the uni has a two week turn around for assignment marking.

As the less literate here in Arizona would say - 10-4!

PS where in NZ are you? My in-laws visited NZ some years ago and raved about it.

 

[Fisher92]

Central QLD, Australia (3/4 the way up (North is up) on the east coast - the coast is still central for some reason -because everyone in Australia lives on the coast I guess)

 

[rude man]

Central QLD, Australia (3/4 the way up (North is up) on the east coast - the coast is still central for some reason -because everyone in Australia lives on the coast I guess)

Oops, Australia! Ah well, my in-laws visited Australia also and raved about it too!
Townsville or Airlie Beach perhaps?

 

[Fisher92]

I live about 3hrs south of Townsville - Airlie is pretty awesome!