Abstract: A free channel detecting method and device which can detect without fail a free channel regardless of the presence of an interfering wave which partly overlaps with the head and end of a slot configuring a time division channel. Output of an envelope detection circuit for detecting an envelope of a received signal is added to a peak hold circuit, and a free channel is detected according to the output of the peak hold circuit.

Abstract: An image display processor displays a real-time three-dimensional image including a player's automobile, a plurality of general automobiles, and a course established in a game space on a display monitor. A driving control assembly is operated by a player to instruct the player's automobile to run on the course. A player's automobile control unit controls the player's automobile to run on the course in response to instructions from the driving control assembly. A rank decision unit ranks the player's automobile using a parameter relative to a skill of the player while the player's automobile is running on the course. The rank decision unit detects whether the player's automobile passes or is passed by one of the general automobiles, and varies the value of the parameter based on the detection of the player's automobile passing or being passed by one of the general automobiles.

Abstract: A power amplifying circuit comprises multi-stage amplifiers connected in cascade, a first switching circuit connected to the last stage amplifier, a second switching circuit connected to the amplifiers other than the last stage amplifier, and an output power adjusting circuit connected to the switching circuit, for controlling a bias voltage. The bias voltage of the last stage amplifier and the bias voltages of the other stage amplifiers are controlled separately from each other by the first and second switching circuits, respectively.