Abstract: A diagnostic circuit for a treble loudspeaker of a loudspeaker combination of a low-frequency output stage, and a method for diagnosing the functionality of the treble loudspeaker. In order to determine the functionality of the treble loudspeaker with relatively little complexity and high reliability, a diagnostic circuit is provided that comprises an HF signal-generating device for outputting an HF voltage signal, at least one terminal for a loudspeaker combination, a measuring resistor that, upon connection of the loudspeaker combination to the terminal, forms therewith a voltage divider circuit, and a measurement device for measuring a complex measured voltage dropping in the voltage divider circuit and for ascertaining a condition of the treble loudspeaker of the loudspeaker combination.

Abstract: A radio warning receiver has a battery or accumulator (7) and means (8) for switching over to battery operation mode when network power (6) fails. Battery power is conserved by turning off (9) power to the end stage (3), placing the warning receiver in a so-called Stand-By Mode, until a control signal is detected (5) which indicates that a warning is to be broadcast. Then, power to the end stage is restored (11) for the duration of the warning broadcast.

Abstract: A warning broadcast system features control signal means, preferably digital, for confirming transmission path integrity prior to broadcast of a spoken warning message. A radio receiver (1) in an alarm center has an auxiliary carrier reception stage (4) which feeds a decoder (5). A coincidence circuit (6) has a first input (7) connected to the decoder output for inputting the received broadcast control signal and a second input (8) for inputting a directly-coupled control signal via a delay line (9) from the control signal generator (10) of the alarm center. When the control signals at the imputs (7, 8) of the coincidence circuit (6) coincide, an output signal (14) actuates a release (15) for the spoken warning message. If a plurality of transmitters (3) having different frequencies are networked, separate receivers (1,1', . . . ) set to the respective frequencies can feed their respective outputs (14, 14', . . . ) to an AND-gate (16) which triggers release (15).

Abstract: A programming unit (1) for ON-OFF switching of a siren or similar warning device can be provided with remote actuation capability by connecting it to a radio receiver tuner (27) and radio data signal decoder (25). The output of the signal decoder (25) is connected to a block decoder (12). Some of the block decoder outputs are connected to a comparison circuit (8) which attempts to match a broadcast siren address with a stored address uniquely identifying the associated siren program unit (1). In the event of a match, a set of flip-flops and gates controls loading of information at other block decoder outputs into a siren program buffer memory (4) and then into an end memory (3) attached to and controlling the program unit (1). After a siren program is performed, end memory (3) is reset.

Abstract: A mounting arrangement for a ventilation or heating system for passenger vehicles having an air duct located in the interior of the vehicle includes an angularly-shaped profile enclosing the air duct. The profile has an upper end portion secured to a clamping device connected to the side wall of the vehicle and a lower end portion which is positioned within a support element formed of an elastic yieldable material having a pair of projecting lips forming a space therebetween to receive the end of the lower end portion and extended to engage this end portion upon insertion therebetween.

Abstract: An arrangement for horizontal central arresting and releasing of an intermediate buffer coupling has a horizontally swingable coupling rod, a guide member at a rear end of the coupling rod and following the swinging of the latter, two rocking levers pivotally mounted on a vehicle and having abutment faces, a roller supported on the guide member and located between the rocking arms so as to abut against their abutment faces, and an actuating device connected with the rocking levers and operative for opening of the latter in the sense of allowing free movement of the intermediate buffer coupling.