Z Thread Starter zian Joined Feb 8, 2011 8 Feb 8, 2011 #1 Signal voltage, Sin=100u Vrms Resistor = 50 ohms im confuseif im going to use Vrms or Vp... urgent please help
Signal voltage, Sin=100u Vrms Resistor = 50 ohms im confuseif im going to use Vrms or Vp... urgent please help
JoeJester Joined Apr 26, 2005 4,390 Feb 8, 2011 #3 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
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
Z Thread Starter zian Joined Feb 8, 2011 8 Feb 9, 2011 #5 should i convert Vrms to Vp (Vp=Vrms/√2) to solve the input power?
t_n_k Joined Mar 6, 2009 5,455 Feb 9, 2011 #6 zian said: should i convert Vrms to Vp (Vp=Vrms/√2) to solve the input power? Click to expand... 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.
zian said: should i convert Vrms to Vp (Vp=Vrms/√2) to solve the input power? Click to expand... 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.
JoeJester Joined Apr 26, 2005 4,390 Feb 11, 2011 #7 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?
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?