flamingo
Member level 4
In order to scale the linearity of a Variable Gain Amplifier, usually use the C/IM3 (the ratio of carrier power to 3rd intermodulation distortion) while the output is kept on 1Vpp (Peak-to-peak voltage) .
While measuring the harmonic distortion (also keep output 1Vpp), and assuming that amplifier gain is Av, we need an input signal with Peak-to-peak voltage 1Vpp/Av. To simulate or measure C/IM3, two tones with same amplitude X (also peak-to-peak), frequency f1 and f2, are needed. Should I use X=1Vpp/Av, or use X=1Vpp/2Av? The performance of C/IM3 of these two conditions differs about 12dB, which one is correct? thank you!!
While measuring the harmonic distortion (also keep output 1Vpp), and assuming that amplifier gain is Av, we need an input signal with Peak-to-peak voltage 1Vpp/Av. To simulate or measure C/IM3, two tones with same amplitude X (also peak-to-peak), frequency f1 and f2, are needed. Should I use X=1Vpp/Av, or use X=1Vpp/2Av? The performance of C/IM3 of these two conditions differs about 12dB, which one is correct? thank you!!