] + gain * y[n-0]<br>    * where gain = e<sup>-dt / T</sup>, T is the time constant in seconds    *    * This filter is stable for time constants greater than zero.    *    * @param timeConstant The discrete-time time constant in seconds.    * @param period       The period in seconds between samples taken by the    *                     user.    */   static LinearFilter<T> 