A focusing apparatus includes a filter unit for performing frequency filtering processing on an image pickup signal, and a focus position detecting unit for detecting a focus position based on the contrast value of the image pickup signal having undergone the frequency filtering processing by the filter unit. The principal program may include, but is certainly not limited to a television broadcast, cable or satellite program, multimedia over the Internet, a paging service, or radio broadcast. The end cap is connected to the top of the first burner membrane. In one embodiment, the system minimizes an error function which is computed with the use of two adaptive filters, each such filter being applied to a corresponding one of the two signals received from the given pair of microphones. As a result, more abrupt source drain junctions may be achieved. First, preprocessing prepares seed variables, requiring a small memory.