The invention provides a reciprocating electric tool having a brushless motor, a plunger, and control means. The receiving method includes determining a control unit for a channel estimation using burst allocation information of selected sectors; extracting pilot symbols from received data based on the control unit; and acquiring a channel estimate value for each transmission unit by performing a Joint Channel Estimation with the extracted pilot symbols that are based on the control unit. The present invention also relates to novel synthetic methods for the preparation of mono- and bis-indolylquinone compounds. Such a seal also reduces wear thus reducing the frequency of seal replacement. In the exemplary embodiment, each application may use both fork and exec in any combination.