Guard space and burst duration monitor for TDMA

The detected envelope as a function of time for QPSK/TDMA signal bursts, which are transmitted through a bandwidth-restricted channel, displays amplitude nulls during the 180 deg phase transitions of the data streams and during the guard spaces between consecutive bursts. This paper presents a circuit design for a burst duration and guard space monitor which is unaffected by the 180 deg phase transition and is fairly immune to the band-limited thermal noise. Measurement accuracy of less than a bit (20 ns) in duration has been consistently recorded using Eb/No not less than 10 dB for both the guard spaces and burst durations.