Symbol timing recovery employs a blind cost criterion from the Bussgang class
of functions, and its stochastic gradient, to generate a timing phase error used
to adjust sampling of received symbols. For one implementation, the estimate is
derived in accordance with the Constant Modulus (CM) criterion and its gradient
via the CM algorithm (CMA), and the estimate is calculated from a sequence of samples.
This estimate is then used to adjust the period and phase of the sample sequence
toward the period and phase of the transmitted symbols, driving the timing phase
error to zero. The values used may be either i) samples themselves, ii) processed
(e.g., interpolated) samples, or iii) equalized and processed samples. In addition,
timing phase error estimates for other cost criteria, including the least mean
squares algorithm, may be generated. These timing phase error estimates are selected
either alone or in combination for deriving the timing phase error used to adjust
the period and phase of the sample sequence.