differential amplifier (transistors)

[maxbrenner]

Need to design a differential amplifier (using transistors) that has a SNR=100. signal is a differential mode signal and noise is common mode signal.
Please help? new at this!

Thank you!

 

[crutschow]

So you need a common-mode rejection ratio (ratio of differential gain to common-mode gain) of 40dB. Look at this.