Preliminary results for a traceable amplitude modulation measurement technique using in-phase and quadrature referencing

We describe a new sampling-oscilloscope based technique to measure the AM and PM components of a modulated RF signal. The method uses in-phase and quadrature referencing to simultaneously demodulate the RF signal and correct the instrument timebase nonlinearities. Preliminary results show a dynamic range of > 80 dB and agreement of better than 1% with existing methods was achieved for a 100 MHz carrier signal amplitude modulated at 20 kHz with a 50% modulation depth.