Image Number 12 for United States Patent #8121646.
The invention is directed to a method and system for equalizing the signal losses over cable runs in a Distributed Antenna System (DAS). In a DAS, two or more antennae are connected to the system by cable runs that can vary widely in length. As a result, the signal loss over a given cable run can also vary widely which can impact the design and deployment of the DAS and reduce antenna spacing. In addition, for a broadband DAS that supports many frequency bands or ranges using a common antenna unit, the signal losses vary with respect to frequency further making it difficult to equalize the cable losses. According to one embodiment of the invention, the method and system provide for measuring and adjusting the signal losses of each cable run to be a predefined value. According to another embodiment of the invention, the DAS can include a hybrid passive-active antenna unit which includes a frequency multiplexer that separates the signal into frequency bands or ranges that are connected to an antenna element associated with a particular frequency band or range. Where a single frequency band needs to be amplified (or attenuated), a single band amplification block (SBAB) can be inserted in the connection between the frequency multiplexer and the antenna element to amplify (or attenuate) the desired frequency band. Where more than one frequency band need to be amplified (or attenuated), a multiband amplification block (MBAB) can be inserted in the connection between the frequency multiplexer and the appropriate antenna element to amplify (or attenuate) the desired frequency bands.