O-QPSK Symbol Timing Estimation

An O-QPSK symbol timing estimation system comprising:

• an early error metric generator configured to generate an early error metric for each sample in a set of phase rotated complex samples that represent an O-QPSK modulated signal, the set of phase rotated complex samples having been generated by sampling a representation of the O-QPSK modulated signal at an O-QPSK symbol rate to generate an initial set of complex samples and applying a phase rotation to one or more of the samples in the initial set of complex samples such that when the representation of the O-QPSK modulated signal is sampled on time each sample in the set of phase rotated complex samples comprises substantially no imaginary component, the early error metric based on an imaginary component of the sample and a sign of a real component of a previous sample;
• a late error metric generator configured to generate a late error metric for each sample in the set of phase rotated complex samples, the late error metric based on an imaginary component of the sample and a sign of a real component of a next sample;
• an early error metric combination module configured to generate a combined early error metric based on the early error metrics for the samples in the set of phase rotated complex samples;
• a late error metric combination module configured to generate a combined late error metric based on the late error metrics for the samples in the set of phase rotated complex samples;
• and
• a sample timing error estimation module configured to estimate a sample timing error based on the early and late combined error metrics.