Palpurul
Member level 3
Helllo guys,
I was wondering how the gain and CMRR of a fully differential amplifier is actually measured. Let's say I have a spectrum analyzer with tracking analyzer or RF gen and spectrum analyzer. They usually all have one input and output, but a fully differential amplifiers have 2 inputs and outputs. Here is how I think I can accomplish to measure these two specifications.
For gain,
The first thing that comes to my mind is to use baluns to create differential signal from single-ended track gen or Rf gen output and connect it to fully differential amps input, and I would connect another balun to the output of the amplifier and convert differential output to single ended output so that the spectrum analyzer can measure the output. I don't know if this is a good method if the amplifiers input/output impedance is non-50 Ohm. The other problem about this is I am not really sure how the normalization process is going to be.
For CMRR,
To measure CMRR I would need to create the same signal at each input. In this case, I might use equal power splitter that is connected between the track gen or Rf gen output to amplifiers input. To sense the the differential output I would use a balun to convert differential signal to single ended signal and feed it to spectrum analyzers input.
What do you think about all of these guys. Are they reliable methods? Do you know any other method related to this topic?
I was wondering how the gain and CMRR of a fully differential amplifier is actually measured. Let's say I have a spectrum analyzer with tracking analyzer or RF gen and spectrum analyzer. They usually all have one input and output, but a fully differential amplifiers have 2 inputs and outputs. Here is how I think I can accomplish to measure these two specifications.
For gain,
The first thing that comes to my mind is to use baluns to create differential signal from single-ended track gen or Rf gen output and connect it to fully differential amps input, and I would connect another balun to the output of the amplifier and convert differential output to single ended output so that the spectrum analyzer can measure the output. I don't know if this is a good method if the amplifiers input/output impedance is non-50 Ohm. The other problem about this is I am not really sure how the normalization process is going to be.
For CMRR,
To measure CMRR I would need to create the same signal at each input. In this case, I might use equal power splitter that is connected between the track gen or Rf gen output to amplifiers input. To sense the the differential output I would use a balun to convert differential signal to single ended signal and feed it to spectrum analyzers input.
What do you think about all of these guys. Are they reliable methods? Do you know any other method related to this topic?