Group delay measurement of frequency down-converter devices using chirped RF modulated signal

This paper discusses how to measure group delay of radio frequency (RF) frequency-converting devices using typical RF Automated Test Equipment (ATE) when conventional S-parameter measurements cannot be done due to the difference between a device's input and output frequencies. We propose using a chirp waveform to modulate an RF generator to sweep the input frequency to an RF device, and describe how to produce an optimal modulation waveform with digital signal processing. We discuss how to implement the test based on our previous work in the baseband domain and how to understand the measurement errors in this RF context. Group delay measurements results are presented for an RF mixer, measured through pre- and post-down-convert RF/IF filters.