Abstract: An amplifier with negative feedback, disposed in an integrated circuit arrangement, comprises an input amplification stage, configured to receive an input signal. A feedback stage configured to receive the output signal provided by the amplification stage, and provide a corresponding feedback signal to the amplification stage. A driver stage, coupled to the input stage, configured to receive the output signal provided by the amplification stage, and provide the output signal of the amplifier.

Abstract: An adapter/converter circuit converts transmissions by a mobile telephone built for one standard (e.g., PCS) from the telephone transmit/base station receive frequency of that one standard to the telephone transmit/base station receive frequency of another standard (e.g., cellular), and converts transmissions by a base station or similar device (e.g., a base station simulator) from the telephone receive/base station transmit frequency of the one standard to the telephone receive/base station transmit frequency of the other standard. The two frequency conversions occur simultaneously on two parallel legs under the control of a PLL dual frequency synthesizer, which is in turn controlled by user input (in the case where the adapter is used to allow, e.g., PCS telephones to be tested on cellular test equipment) or by the base station (in the case where the adapter is used to allow, e.g., PCS telephones to be used with a cellular base station).

Abstract: A transceiver operable in both the cellular and PCS frequency bands which uses a single voltage controlled local oscillator in an intermediate frequency stage for both the cellular and PCS signals. The oscillator is operative for upconverting transmitter signals and downconverting receive signals for both cellular operation and PCS operation. A second voltage controlled local oscillator in a stage between the transceiver antenna and the intermediate frequency stage is operative for only PCS operation to upconvert PCS transmitter signals and to downconvert PCS receive signals. This is accomplished by the use of a switchable intermediate frequency local oscillator in the transmitter path of both the cellular and PCS signals.

Abstract: A fixed dual frequency band antenna for a dual frequency band radio transceiver where the two frequency bands are not harmonically related. The antenna includes a straight radiating antenna portion terminated by a helical wire radiating antenna portion, with the total electrical length of the antenna being approximately three quarters of the wavelength at the center frequency of the higher of the two frequency bands. A conductive radiating cap terminates the helical portion and a conductive antenna base is connected to the straight portion at the end opposite the helical portion. A matching circuit coupled between the base and the transceiver circuitry is arranged to substantially cancel the reactive portion of the impedance of the antenna for both frequency bands and to substantially equalize the resistive portion of the impedance of the antenna to the resistive portion of the output impedance of the radio transceiver.

Abstract: In one embodiment the present invention includes an arrangement for monitoring RF signals for use in a base station, said arrangement comprising a demodulation circuit operable to demodulate RF signals, an RF signal transceiver, and a controller. The RF signal transceiver is operable to transmit downlink RF signals to a wireless terminal and receive uplink RF signals from the wireless terminal.

Abstract: A dual frequency band antennas system where the two frequency bands are not harmonically related includes first and second antenna sections. The first antenna section comprises a straight rod, with the length of the rod being at least one quarter wavelength at the center frequency of the lower of the two frequency bands. The second antenna section includes a straight portion terminated by a helical wire portion, with the total electrical length of the second antenna section being substantially equal to the length of the straight rod. A conductive antenna base is connected to at least one of the first and second antenna sections. A matching circuit coupled to the base is arranged to substantially cancel the reactive portion of the impedance of the connected antenna section for both frequency bands and to substantially equalize the resistive portion of the impedance of the connected antenna section to the resistive portion of the output impedance of the radio transceiver to which the antenna system is coupled.

Abstract: A band pass-band reject filter in which the filter housing which comprises the resonant cavity is contained within an annular wall that is supported at each end by an end plate. The filter is connected to an instrument rack or the like by the distal ends of bolts which extend between the end plates and which lie closely along side the annular wall. The end plates are soldered to the annular housing. The bolt heads are soldered to the end plate and their shafts are soldered to the side wall.