Abstract: The present invention is related to a device for generating waveguide modes for use in a feed horn of a satellite antenna system, said waveguide modes comprising at least one excitation mode of higher order than the fundamental mode, said device comprising a waveguide containing a first waveguide section with at least three longitudinal slots extending in the inner side of said waveguide, characterized in that said waveguide contains a second waveguide section with at least three longitudinal slots extending in said inner side of said waveguide.

Abstract: The present invention is related to a device for generating waveguide modes for use in a feed horn of a satellite antenna system, said waveguide modes comprising at least one excitation mode of higher order than the fundamental mode, said device comprising a waveguide containing a first waveguide section with at least three longitudinal slots extending in the inner side of said waveguide, characterised in that said waveguide contains a second waveguide section with at least three longitudinal slots extending in said inner side of said waveguide.

Abstract: The present invention is related to a circuit (1) for detecting activity in a burst-mode receiver. The circuit is arranged for receiving an input signal (2) comprising a preamble. The circuit comprises a differentiator (11) for detecting signal transitions in the input signal (2) whereby the preamble comprises information on operating said differentiator (11). In a preferred embodiment, the information is a time constant. The circuit further comprises an integrator (12) arranged for being fed with an output of the differentiator. The resulting signal is compared to a reference (16). If this reference is crossed, activity is detected. In an embodiment a front-end circuit is presented comprising next to a circuit for detecting activity, a reset circuit arranged for resetting the front-end circuit and a clock phase alignment circuit arranged for recovering the phase.

Abstract: The present invention relates to a method and apparatus for modification of a connection between a transmitting subscriber and a receiving subscriber in a communications system, which is based on data compression, within a switching center, with a data frame which arrives in the switching center and is formatted on the basis of a framing protocol being replaced independently of the length of the data frame by a new data frame formatted on the basis of the framing protocol, such that additional information can be fed into the connection without any loss of quality or time.

Abstract: Efficient adjustment of tones and announcements are equalized in the conversation of a mobile radio telephone subscriber by a common air interface (4) enabling an exchange to occur between several transmission modes characterized by different compression of said conversation. This is achieved by means of a device and a method for adjusting an acoustic sequence (11; 12; 13; 14; 15; 16; 17; 18) in the speech channel of a common air interface (4) for a subscriber (2) of a mobile radio telephone network (4, 3, 5). According to the invention, a transmission mode (A; B; C) which is to be used on the speech channel can be selected (3,5) from several transmission modes defined by differing degrees of compression of speech sequences (8) of the subscriber (2) on the common air interface. An adjustable acoustic sequence is stored in several compression data sets (11, 12, 13, 14, 15, 16, 17, 18) whose compression respectively corresponds to the compression of at least one of the transmission modes (A; B; C:).

Abstract: The present invention relates to a method and apparatus for modification of a connection between a transmitting subscriber and a receiving subscriber in a communications system, which is based on data compression, within a switching center, with a data frame which arrives in the switching center and is formatted on the basis of a framing protocol being replaced independently of the length of the data frame by a new data frame formatted on the basis of the framing protocol, such that additional information can be fed into the connection without any loss of quality or time.