Abstract: Mowers are provided with a safety system to prevent obstacles, such as animals, located in the field from being hit by cutters of the mower. The safety system includes a control unit and at least one detector to detect the obstacle and then provide a warning signal to the control unit, when the obstacle is detected. The control unit provides a separation signal to at least one safety device in response to receiving the warning signal, and the at least one safety device causes separation between the obstacle and the at least one cutter in response to receiving the separation signal. The safety device may be at least one shield which is movable between a retracted position and a protecting position in which it extends in front of the at least one cutter to prevent contact between the at least one cutter and the obstacle.

Abstract: Mowers are provided with a safety system to prevent obstacles, such as animals, located in the field from being hit by cutters of the mower. The safety system includes a control unit and at least one detector to detect the obstacle and then provide a warning signal to the control unit, when the obstacle is detected. The control unit provides a separation signal to at least one safety device in response to receiving the warning signal, and the at least one safety device causes separation between the obstacle and the at least one cutter in response to receiving the separation signal. The safety device may be at least one shield which is movable between a retracted position and a protecting position in which it extends in front of the at least one cutter to prevent contact between the at least one cutter and the obstacle.

Abstract: A transmitter with a pulse width modulation amplifier includes an inner positive feedback loop, which has a self oscillating modulator and a switching stage and is connected to an LP filter. Outer feedback loops from the LP filter respective from an output transformer are coupled to a compensation block connected to the inner loop. An input telecommunications signal, fed via the compensation block, is superimposed on a carrier from the modulator into a pulse width modulated signal, which is amplified, filtered and fed to the transformer. The input signal is compared with feedback signals. Phase shift caused by the LP filter is partly compensated by the inner loop. A switching frequency in the modulator therefore can be comparatively low. An output impedance is kept on a predetermined level, enabling connection of a receiver. Advantages are low power dissipation, high packing density, high frequency bands and use in bidirectional communication.

Abstract: A transmitter with a pulse width modulation amplifier includes an inner positive feedback loop, which has a self oscillating modulator and a switching stage and is connected to an LP filter. Outer feedback loops from the LP filter respective from an output transformer are coupled to a compensation block connected to the inner loop. An input telecommunications signal, fed via the compensation block, is superimposed on a carrier from the modulator into a pulse width modulated signal, which is amplified, filtered and fed to the transformer. The input signal is compared with feedback signals. Phase shift caused by the LP filter is partly compensated by the inner loop. A switching frequency in the modulator therefore can be comparatively low. An output impedance is kept on a predetermined level, enabling connection of a receiver. Advantages are low power dissipation, high packing density, high frequency bands and use in bidirectional communication.