Highly portable, handheld instrument which can be pointed at the produce to be checked. With the signaling transport speed of the dual PHY based path being an order of magnitude greater than that of any of the plurality of communication paths with which the IAD is interfaced, the IAD of the invention provides effectively real time support for different communication requirements, including TDM, ATM, HDLC, and the like. The amplified signal is passed to a filtering circuit for filtering. The plate has a first end section at which a first tab is created and a second end section overlapping the first end section with a slot through which the first tab extends to secure the first and second end sections together. And the second delay means includes at least one type of circuit among the type of an analog delay circuit and a digital delay circuit. A heater 33 that applies heat to the dilution air, a Pd catalyst 341 and a Pt catalyst 342 are arranged in this order on a flow channel where a dilution air used for diluting the measurement object gas flows, and N2O in the dilution air is oxidized to NOx or reduced to N2 by the Pd catalyst 341 and the Pt catalyst 342.