An introduction to envelope constrained filter design

Envelope constrained filter design is concerned with the time domain synthesis of a filter whose response to a specified input signal stays within prescribed upper and lowe bounds and in addition has minimal noise enhancement. In many practical applications, a "soft" approach, such as least mean square, is not the most suitable and it becomes necessary to use "hard" constraints such as the ones considered in the paper. We present an overview of key ideas related to robust continuous time envelope constrained filter design.