A communication system includes a transmitter and a receiver. The planetary gearset is connected to the shift element in a detachable manner. The optimum is a function of the price of feedstocks, products and intermediate streams as provided by the refinery planning optimization. , a specific % acceptable, where the acceptability value relates to empirically derived image quality as perceived by a human viewer. The nonvolatile memory may store a window of measurement data of the vacuum gauge that is updated at predetermined time intervals and in response to an event, such as an error event, to aid in investigating the cause of vacuum gauge malfunction or failure. The channel estimation circuit makes a judgment on the estimated channel state and carries out masking on a part of the complex delay profile in accordance with the judgment for suppressing the noise.