Hi,
I designed a three-stage BJT amplifier with common emitters on the first and second stages and a common collector on the last. I was able to design the circuit so that the 50mV, 10kHz input was amplified to 5V for a gain of a 100.
The problem I am having is the total harmonic distortion. The design specifications said it has to be some 0.x%, but I am getting around 247%. In Pspice, under the transient option, I enabled Fourier, set the center freq to 10khz and had 9 total harmonics. I set the variable at the output node the resistive load, simulated, and got this extremely high percentage. My output is a smooth curve in Pspice. Also, I built the circuit in lab and I get the 100 gain with a smooth curve on the oscilloscope.
What are ways to lower the THD? Is the problem with my design or did I simulate incorrectly? I attached a picture of my circuit with node voltages. Any help will be appreciated!
Thank you.
I designed a three-stage BJT amplifier with common emitters on the first and second stages and a common collector on the last. I was able to design the circuit so that the 50mV, 10kHz input was amplified to 5V for a gain of a 100.
The problem I am having is the total harmonic distortion. The design specifications said it has to be some 0.x%, but I am getting around 247%. In Pspice, under the transient option, I enabled Fourier, set the center freq to 10khz and had 9 total harmonics. I set the variable at the output node the resistive load, simulated, and got this extremely high percentage. My output is a smooth curve in Pspice. Also, I built the circuit in lab and I get the 100 gain with a smooth curve on the oscilloscope.
What are ways to lower the THD? Is the problem with my design or did I simulate incorrectly? I attached a picture of my circuit with node voltages. Any help will be appreciated!
Thank you.