| 摘要 |
A distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas. The cellular band outputs of these microcell base station devices are used to modulate a 60 GHz (or higher) carrier wave, yielding a group of subcarriers on the 60 GHz carrier wave. This group will then be transmitted in the air via analog microwave RF unit, after which it can be repeated or radiated to the surrounding area. The repeaters amplify the signal and resend it on the air again toward the next repeater. In places where a microcell is required, the 60 GHz signal is shifted in frequency back to its original frequency (e.g., the 1.9GHz cellular band) and radiated locally to nearby mobile devices. A distributed antenna system is provided that frequency shifts the output of one or more microcells to a 60 GHz or higher frequency range for transmission to a set of distributed antennas. The cellular band outputs of these microcell base station devices are used to modulate a 60 GHz (or higher) carrier wave, yielding a group of subcarriers on the 60 GHz carrier wave. This group will then be transmitted in the air via analog microwave RF unit, after which it can be repeated or radiated to the surrounding area. The repeaters amplify the signal and resend it on the air again toward the next repeater. In places where a microcell is required, the 60 GHz signal is shifted in frequency back to its original frequency (e.g., the 1.9GHz cellular band) and radiated locally to nearby mobile devices. Exemplary embodiments of foam pumps, refill units and dispenser systems are disclosed herein. Some embodiments have a foam pump that includes a chamber having a liquid inlet, a vacuum outlet, a pressurized air inlet and a liquid air mixture outlet. The exemplary foam pump includes a liquid inlet valve located in fluid communication with the liquid inlet to allow liquid to enter the chamber and to prevent liquid from exiting the chamber through the liquid inlet. Vacuum pressure applied to the vacuum outlet causes fluid to flow through the liquid inlet, past the liquid inlet valve and into the chamber. Pressurized air flows through the pressurized air inlet and mixes with the liquid and the liquid air mixture is forced out of the liquid air mixture outlet. The foam pump includes a mix media in fluid communication with the liquid air mixture outlet. The liquid air mixture flows through the mix media and flows through an outlet to be dispensed as a foam. |
