摘要:
A dynamically variable beamwidth and/or variable azimuth scanning antenna includes a plurality of active radiating columns and a plurality of continuously adjustable mechanical phase shifters. The columns define a beam having a beamwidth and an azimuth scan angle. Each phase shifter has an independent remotely controlled drive and is directly electrically connected to a respective radiating column. The phase shifters are independently operated to vary the beamwidth and/or azimuth scan angle of the beam defined by the plurality of active radiating columns.
摘要:
A repeater and associated method of use includes at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction. A radio frequency uplink path and a radio frequency downlink path are coupled between the antennas. At least one of the radio frequency uplink path or the radio frequency downlink path includes an adaptive cancellation circuit. The adaptive cancellation circuit is configured to generate a cancellation signal without requiring an injected signal. The cancellation signal, when added to a radio frequency signal in the respective uplink and downlink paths, substantially reduces feedback signals present in the radio frequency signal.
摘要:
A repeater and associated method of use includes at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction. A radio frequency uplink path and a radio frequency downlink path are coupled between the antennas. At least one of the radio frequency uplink path or the radio frequency downlink path includes an adaptive cancellation circuit. The adaptive cancellation circuit is configured to generate a cancellation signal without requiring an injected signal. The cancellation signal, when added to a radio frequency signal in the respective uplink and downlink paths, substantially reduces feedback signals present in the radio frequency signal.
摘要:
A repeater and associated method of use includes at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction. A radio frequency uplink path and a radio frequency downlink path are coupled between the antennas. At least one of the radio frequency uplink path or the radio frequency downlink path includes an adaptive cancellation circuit. The adaptive cancellation circuit is configured to generate a cancellation signal without requiring an injected signal. The cancellation signal, when added to a radio frequency signal in the respective uplink and downlink paths, substantially reduces feedback signals present in the radio frequency signal.
摘要:
A repeater and associated method of use includes at least one antenna element for communicating in one direction and at least one antenna element for communicating in another direction. A radio frequency uplink path and a radio frequency downlink path are coupled between the antennas. At least one of the radio frequency uplink path or the radio frequency downlink path includes an adaptive cancellation circuit. The adaptive cancellation circuit is configured to generate a cancellation signal without requiring an injected signal. The cancellation signal, when added to a radio frequency signal in the respective uplink and downlink paths, substantially reduces feedback signals present in the radio frequency signal.
摘要:
A flat-panel repeater includes a housing having a pair of oppositely facing surfaces, at least one antenna element mounted to each of the surfaces for radiating energy in a direction opposite to that of an antenna element mounted to the other of the surfaces, and an electronic circuit mounted within the housing and operatively coupling signals between at least one antenna element on each of the oppositely facing surfaces of the module. Isolation between the antennas on opposite sides of the repeater is improved by various techniques, such as use of adaptive cancellation which removes a significant portion of the feedback signal power, therefore increasing the total system isolation by the same amount. This additional isolation can be used to achieve greater system gain, and therefore significantly extend the range of the system. The repeater may also include a beamforming arrangement for creating a desired antenna pattern of one antenna relative to a base station and a desired antenna pattern of the other antenna relative to subscriber equipment.
摘要:
An antenna system includes a plurality of cascading power dividers that work in conjunction with a plurality of mechanical phase shifters to vary a beamwidth and/or an azimuth scan angle of a beam that radiates from active columns. Each phase shifter has an independent remotely controlled drive and is directly electrically connected to a respective radiating column. The radiating columns include cross dipole antenna elements.
摘要:
The present invention relates to methods for producing a polypeptide, comprising: (a) cultivating a Bacillus host cell in a medium conducive for the production of the polypeptide, wherein the Bacillus cell comprises a nucleic acid construct comprising (i) a tandem promoter in which each promoter sequence of the tandem promoter is operably linked to a single copy of a nucleic acid sequence encoding the polypeptide and alternatively also (ii) an mRNA processing/stabilizing sequence located downstream of the tandem promoter and upstream of the nucleic acid sequence encoding the polypeptide; and (b) isolating the polypeptide from the cultivation medium. The present invention also relates to methods for producing a polypeptide, comprising: (a) cultivating a Bacillus host cell in a medium conducive for the production of the polypeptide, wherein the Bacillus cell comprises a nucleic acid construct comprising (i) a “consensus” promoter having the sequence TTGACA for the “−35” region and TATAAT for the “−10” region operably linked to a single copy of a nucleic acid sequence encoding the polypeptide and (ii) an mRNA processing/stabilizing sequence located downstream of the “consensus” promoter and upstream of the nucleic acid sequence encoding the polypeptide; and (b) isolating the polypeptide from the cultivation medium.
摘要:
A variable force exerting clamp assembly having a variable clamping area. A stretchable strap which deforms or "thins" to a smaller width in response to stretching is provided with a first work-engaging clamp secured at one end thereof and a second movable clamp which is slidable between the ends of the strap. The clamps are disposed for engaging a workpiece or workpieces between each other, and tension is applied until the strap is stretched to exert the desired force on the members, whereby, upon release of the tensional force, the strap tends to assume its original configuration, and the second clamp exerts a clamping force on the strap responsive to the strap expanding to its original width.
摘要:
An adjustable device that provides a secure anchor in a crevice or other irregularity. The anchor may be used to assist rock climbers, rescue groups, military personnel, construction workers, etc. The device is comprised of a spring loaded sleeve mounted on a first end of a threaded shaft and limited in its movement on the shaft by a pin and slot arrangement. The sleeve provides a means for adjusting the length of the device. A first locking means releasably secures the sleeve in a retracted position, and a second locking means secures the sleeve at the desired extended position. A lever assembly is provided at the second end of the device in such a manner that a force applied to an attachment point of the assembly will be translated along the longitudinal axis of the device.