The quadratic estimator of Equation (374a) makes use of an N × N matrix Q of weights, the (s, t)th element of which is denoted by Qs,t. The weighted multitaper estimator Sˆ (WMT)(·) of Equation...

The quadratic estimator of Equation (374a) makes use of an N × N matrix Q of weights, the (s, t)th element of which is denoted by Qs,t. The weighted multitaper estimator Sˆ (WMT)(·) of Equation (352b), which is defined in terms of the eigenspectra
  of Equation (352a), is an example of a quadratic estimator. Determine