Abstract: A skin stimulation brush includes stimulation brush pins, each including a base bottom member made of a metal, which is connected to an electric circuit so as to allow conduction of electricity from the electric circuit; a body member being an elongated tubular body, which has a proximal end portion at which the base bottom member is disposed; an electrode member connected to an opening of the body member on a distal end side, and having a distal end being exposed; and a metal shaft inserted into a tubular inner portion of the body member with an air gap, which is configured to couple the base bottom member and the electrode member while being in a compressed state in a length direction of the body member. The metal shaft has pliability that allows bending in a radial direction. The body member has elasticity that allows bending in a radial direction.

Abstract: A coding device in which N digital signals (time-sequential sampled data), obtained by sampling and quantizing analog video signals, are brought together in one group (N being an integer greater than two) and coded. Among these N sampled data, at least one of them serving as a reference is coded with a number of quantization bits n, which is so great that errors due to the quantization can be neglected, and for the other sampled data the difference between the reference sampled data and each of the others is compressed and coded with a number of bits, which is smaller than n. In this way, even if a coding error is produced; effects thereof are restricted within the gorup where it is produced they are not exerted on the other groups, and thus error propagation does not occur.

Abstract: A method of producing a tracking control signal in a rotary head type magnetic recording and reproducing apparatus and a rotary head type magnetic recording and reproducing apparatus capable of a proper tracking by the use of the tracking control signal.