This system automatically adjusts the static convergence drift that springs from change of temperature, influence of terrestrial magnetism and etc. when we use projectors. The system is composed of detector, calcuiator, adjustment data output and pattern generator for detection. The system can automatically keep the convergence drift within the range of less than 0.067% of a picture hight (Hivision). It takes no more than 255sec. to complete the adjustment.

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Compatibility tests on FM multiplex broadcasting for mobile reception have been done. Causes which generate interference in receivers have been unveiled. First, the characteristics of various kind of receivers have been measured multiplexing MSK signals with the existing sound signals. Second, the interference which is caused by the multiplexed signals under multipath propagation have been measured in indoor tests. Third, after the end of daily FM programs, the test signals multiplexed by L-MSK method have been broadcasted from NHK FM Tokyo (82.5MHz) station. The audio impairment by L-MSK signals has been surveyed by questionnaire. The minimum injection level of L-MSK has been decided four percentage as results of detail analyses.

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The effects of the filter order of two-dimensional optimal YC separating filters on the filter performance were evaluated in terms of four indicators, the signal to noise ratio, the power of chrominance error signal, the power of leaked luminance signal and the power of extracted chrominance signal. It is shown that the increase of the order beyond 6×6 results in little improvement of the performance of the filters.

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stable automatic iris control was desired to compensate for various backlighting and excessive frontlighting for photographic images. In this paper, we present iris control based on distribution of luminance for multiple regions of an image. The degree of backlighting v_b and excessive frontlighting v_f of Various images can be determined by using fuzzy inference rules whose inputs are the interval mean from luminances of 80 regions. A discrimination between two kinds of images is Conducted based on the distribution of mean luminances for 4 regions into which the total image has been divided. Subsequently the compensation level is determined by alternating v_b and v_f based on results from the discrimination between the two kinds of images.

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