A Novel Technique for Characterizing the Absolute Group Delay and Delay Linearity of Frequency Translation Devices

A novel technique for measuring the delay characteristics of a mixer using the time domain option on a Vector Network Analyzer (VNA) is reported. The technique uses the measured reflection coefficient from a single mixer and utilizing the time domain option on the VNA, the data is transformed into the impulse response of the mixer. By placing several types of loads on the output port of the mixer, the absolute delay and delay linearity through the mixer can be determined. Typically broadband digital communication systems may often require delay linearity of several hundred picoseconds. As demonstrated by the measurements reported, this technique allows delay linearity to be measured with less than 12 psec peak deviation and less than one picosecond resolution.