I posted the same question on the math forum as well.
I was reading this paper on direct conversion receiver, and there's a part on the math of calculating the DC offset due to self mixing that I am a little confused about.
http://www.ee.ucla.edu/~brweb/papers/Journals/RTCAS97.pdf
Refer to 4th paragraph in page 3 of the paper.
1) It says the LO has a Vpp of 0.63v (0dBm in a 50 ohm system)... how does a 0.63v translate to a 0 dBm in a 50 ohm system?
2) following the rest of the paragraph. Suppose I start off with 0 dBm at the mixer, then it goes down to -60dBm at LNA due to the attenuation, then add the LNA/mixer gain of 30dB, that means it would put the self-mixing signal at -30dBm at the output of the mixer? how does -30dBm at the output translate to 10mV DC offset?
3) with a 10mV dc component at the input into an amplifier, how easily would that drive the amplifier into saturation? wouldn't it depends on how much rail to rail voltage is there and how much the peak to peak signal swing is?
I was reading this paper on direct conversion receiver, and there's a part on the math of calculating the DC offset due to self mixing that I am a little confused about.
http://www.ee.ucla.edu/~brweb/papers/Journals/RTCAS97.pdf
Refer to 4th paragraph in page 3 of the paper.
1) It says the LO has a Vpp of 0.63v (0dBm in a 50 ohm system)... how does a 0.63v translate to a 0 dBm in a 50 ohm system?
2) following the rest of the paragraph. Suppose I start off with 0 dBm at the mixer, then it goes down to -60dBm at LNA due to the attenuation, then add the LNA/mixer gain of 30dB, that means it would put the self-mixing signal at -30dBm at the output of the mixer? how does -30dBm at the output translate to 10mV DC offset?
3) with a 10mV dc component at the input into an amplifier, how easily would that drive the amplifier into saturation? wouldn't it depends on how much rail to rail voltage is there and how much the peak to peak signal swing is?