Measurement of effective team game playing time - using referee operated acoustic signal transmitter and receiver tuned to transmitted frequency

摘要

The game is a sports team game with a reference and a fixed playing time. Play interruptions ordered by the referee are signalled by him by a whistle. The equipment comprises at least one timing device for measurement of the time, with a control input for interruption and restarting of measurement. A receiver for wireless transmission of signals has an output connected to the timer control input. The referee has a portable transmitter for delivery of signals to the receiver. A switch, operated by the referee activates the transmitter at the beginning or end of an interruption. the portable transmitter has a device emitting acoustic signals, and the receiver has at least one stage selectively responding to the transmitted frequencies.