need some help! how to calculate the input signal power in dB given the ff. value...

Signal voltage, Sin=100u Vrms
Resistor = 50 ohms

im confuseif im going to use Vrms or Vp... urgent please help

 

need help... for my assignment

 

what is your 0 dB reference? 0 dBm? 0 dB/uV? 0 dBfW?

The ebook chapter concerning dB is http://www.allaboutcircuits.com/vol_3/chpt_1/5.html

 

tnx sir joejester!

 

should i convert Vrms to Vp (Vp=Vrms/√2) to solve the input power?

 

You have already stated in your first post that the sinusoidal voltage is 100uV RMS. Why would you bother calculating Vp? Also, Vp is not given by

Vp=Vrms/√2

Rather

Vrms=Vp/√2

and Vp=√2xVrms.

Use the given rms value of 100uV for your calculations.

 

If the fact that the resistance specifies 50 ohms might indicate your answer should be referenced to dBm, dBfW, or dB/uV. As OP, you need the reference so you will know the your divisor in the equation.

http://en.wikipedia.org/wiki/Decibel#Common_reference_levels_and_corresponding_units

So, what did you find for your final answer?