Abstract: The invention relates to a detection tag for the detection of the reproductive status of animals. The detection tag includes two signal transmitters, one of which is activated when the animal is mounted by another animal and the other of which is always on. It can therefore be determined whether the tag is activated or missing. A detection tag in one embodiment comprises a first surface affixable to the hide of an animal, a second and opposite surface including abradable material, first and second electronic signal transmission means configured to transmit first and second electronic signals having detectably different characteristics, the detection tag being configured such that removal of some or all of the abradable material alters the ability of the detection tag to transmit the first signal or alters a characteristic of the first signal.

Abstract: A circuit for generating an audio chime signal, for use on a passenger aircraft, for example to attract the attention of the passengers prior to a public announcement. High and low frequency oscillators are switched on for respective time periods, the low frequency oscillator being switched on after the high frequency oscillator. Decay circuitry causes a progressive decay in the output of each oscillator and a sine shaper removes harmonics of the high and low frequencies.