An orthogonal frequency division multiplexing system provided for communication includes an OFDM transmitter and an OFDM receiver. The additive comprises a hydroxy-terminated polyoxyalkylate chain containing polymer having at least one oxygen atom and at least one nitrogen atom and, optionally, other components such as a solvent, an acid or mixtures thereof. A post-heat section is disposed within the vacuum chamber immediately downstream of the vapor deposition apparatus in the conveyance direction of the substrates. The metal containing layer is annealed to drive metal into the substrate to form self-aligned contact regions in a metal alloy formed in the substrate within the dopant regions. With different combinations, large or small bandwidth filters can be made without very small or very large spacing between resonators. The selective sharpening filter can be implemented quickly by using implementations of the existing selective smoothing filter and a derived matching non-selective smoothing filter as black boxes and combining their outputs in a simple manner.