Abstract: A filter for an air cleaner is produced by impregnating a fiber web composed of one or more layers with a liquid binder in the form of solution, suspension, or emulsion. The impregnated fiber web is dried such that the solvent or dispersing medium on one side evaporates faster then that on the other side. As the result, more binder is deposited on one side than on the other side; in other words, a gradient of binder distribution is formed. The thus-produced filter has such a structure that the voids among fibers continuously change across the thickness, while fibers are bonded together by the binder. The filter thus produced can collect more dust than a conventional one.

Abstract: When separating a composite video signal into a luminance signal component and the chrominance signal component by the use of filtering, a high frequency cross-talk component of the luminance signal is present in the chrominance signal and this may be cancelled using a horizontal correlator that imparts time delays and detects maximum and minimum levels relative to a reference level. In such luminance cross-talk cancellation by means of the horizontal correlator the usable chrominance signal length is shortened by almost one wave length out of four, thereby reducing the usable chrominance signal each time such luminance/chrominance signal separation occurs in a dubbing operation, for example. By utilizing two chroma separators in series each including a nonadditive mixer circuit, the resultant output from the second chroma separator circuit has substantially the same length as the portion of the composite video signal fed as the input.