Calcium hydroxide in which the average secondary particle diameter at a cumulative percentage of 50% by number in a particle size distribution is 2. The trimming structure includes respective trimmable circuit structures included in the first and at least one second functional blocks, and trimming configuration storage for storing trimming configurations for the trimmable circuit structures. The validation is performed by one or more circuits at wire speed. In other embodiments, the refractive-index profile of the fiber or other waveguide is adjusted to reduce the numeric aperture and thus reduce the angle of light that will remain in the cladding. The first portion of the audio signal is modified in accordance with the graded response.