The Journal of the Institute of Television Engineers of Japan

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Characteristics of smooth pursuit eye movements elicited by auditory stimuli are studied in comparison with those by visual stimuli. The amplitude of response is smaller and the delay time is longer for auditory stimuli than for visual stimuli. Frequency characteristics show similar low-pass shapes in both cases.
The error of direction or motion between a target and the line of sight is detected through the retina for the visual stimulus and is generally considered to be minimized by the feedback control in the eye movement system. To obtain unity gain in the low-frequency region in such a negative feedback control system, the gain of the feedforward path of the system should be extremely high.
For auditory stimuli, feedback control does not take place since the error detector does not exist, so the frequency characteristics are measured as those of the feedforward path of the smooth pursuit system. The frequency characteristics show similar low-pass shapes for both auditory and visual stimuli suggesting that the smooth pursuit system works as a feedforward system responding to a perceived motion in both cases and is not a generally conjectured feedback control system.

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CCIR recommends a practical method for measuring the noise in existing TV systems such as NTSC, PAL, and SECAM. The method requires only a simple passive network, called the weighting network, between a noise source and an r. m. s. meter. The present paper examines an HDTV noise-weighting network by subjectively assessing existing TV and HDTV noise disturbances. The bridge-T type network with a time constant of 90 ns works well for HDTV. From a view point of practical use, a 120 ns network can be used for existing TV and for HDTV.

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A method is proposed to improve the image quality of mobile telephone facsimile machines. The method enables the control of action of the fax modem based on information on signal conditions.
First, abnormalities, caused by fading during transmission, are detected in the input signal. An improvement in image quality in the receiving modem is achieved by compensating for this poor signal.
Control signals, calculated using signal errors, and tap coefficients for the modem equalizer are used to control the action of the receiving modem (such as equalization and recovery of carrier and timing).
Using computer simulation to compare our method with existing methods, we confirmed the following : (1) it is possible to accurately detect the control signal which corresponds to abnormalities, (2) the modem can be controlled using these signals, and (3) the line errors in the transmitted image can be decreased.

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