Abstract: A distributed antenna system is provided which is formed from a series of modular stages interconnected by cables. Each stage may include an antenna, a filter, a compensating amplifier and preferably elements for impedance matching to connecting cables. Connecting stages also include a coupler for combining the output from the stage antenna with the output from the preceding stage and passing the combined signal to the stage output. Where the stages are part of a transmitting system, the coupler is replaced by or functions as a splitter, an input thereto from, for example, a preceding stage, being applied to the stage antenna and to the stage output.

Abstract: A pressure transducer having a first pair leads for receiving an excitation voltage and a second pair of leads between which it can supply a voltage corresponding to a pressure applied to it is provided with means for placing at least one electrical load between said first pair of leads. The leads are connected to a pressure monitor having means for indicating the pressure represented by the voltage between said second pair of leads and means for indicating an alarm condition when said signal indicates a pressure outside of a given limit. The monitor has local means for disabling the alarm indicating means and means for setting the indicated pressure to zero. The monitor also has means responsive to a first given current in said first pair of leads for disabling said means for indicating an alarm and means responsive to a second given current in said first pair of leads for causing said means for indicating pressure to indicate a zero pressure.