In a processor of a wireless image transmission system that transmits, by radio communication, an image signal obtained by converting an image obtained by an endoscope apparatus, a communication state detection unit monitors a communication state of radio communication. The shutter element moves towards and away from the ejector between a position where it closes the ejector and in which a pad, fixed to one end of it, is in contact with the ejector, and a position where the ejector is left open. The electrochemical device shows excellent low-temperature characteristics, high-temperature life characteristics and safety. A training-sequence noise is formed according to training-sequence noise information of the training sequence. Step coefficients and corresponding to input signal amplitude value rn computed by an amplitude computation section are output from the memory to multipliers. The aspects may be used together in a single surgical procedure or separately in different surgical procedures.