Abstract: A circuit arrangement is described with the aid of which a constant field strength of an HF signal radiated by a transmitting device (10) having an exchangeable antenna (12) can be achieved. Associated with the exchangeable antenna (12) is an antenna-specific component R1 from which in the operating state a control signal can be tapped after connection of the antenna (12) to the transmitting device (10). Said control signal is applied in the transmitting device (10) to an assembly (28) for influencing the transmitting power.

Abstract: The present invention is manner of synchronization in a video overlay system for overlay of an internal video signal upon an external video signal. In the video overlay system of the present invention the horizontal synchronization pulses of the external video signal are detected to enable generation of the internal video signal having synchronized horizontal lines. This is achieved by generating a video clock signal for control of video signal generation at a frequency that is a multiple of the frequency of the horizontal lines of the external video signal. The vertical synchronization signal of the external video signal is detected in the preferred embodiment to enable generation of the internal video signal having video frames in synchronism with those of the external video signal.