  Using a time-gated dual quadrature spectral interferometry technique, for the
first time we demonstrate single-shot characterization of both spectral
amplitude and phase of ~1THz bandwidth optical arbitrary waveforms generated
from a 10 GHz frequency comb. Our measurements provide a temporal resolution of
1ps over a record length of 100ps. Singleshot characterization becomes
particularly relevant when waveform synthesis operations are updated at the
repetition rate of the comb allowing creation of potentially infinite record
length waveforms. We first demonstrate unambiguous single shot retrieval using
rapidly updating waveforms. We then perform additional single-shot measurements
of static user-defined waveforms generated via line-by-line pulse shaping.
