An engine sound synthesizer includes an engine sound storing section, and a synthetic engine sound data generating section which generates synthetic engine sound data on the basis of engine sound data stored in the engine sound storing section. A mask is formed above the substrate. The ability of embodiments to provide such feature may allow tenants to efficiently and effectively implement security measures for in-bound emails. Based upon the Model and the data received from the counters and the assumption that cache decays exponentially, a nominal lifetime of a cache line is computed and the state of the system is manipulated in accordance with the computed lifetime of the cache line. In one embodiment, a first and second signal of the dual band signal are up-sampled at a sampling rate that is based at least in part on the bandwidth of at least one of the first and second signals and based at least in part on an intermediate frequency by which the first and second signal are tuned before pre-distortion of the tuned signals. The system also includes subscriber stations capable of receiving and extracting Logical Node identification information from a data stream.