Abstract: A radio frequency (RF) power combiner for connecting multiple base transceiver stations with one antenna assembly includes at least one combining device coupled to at least two base transceiver stations for combining signals generated thereby into a combined signal for being transmitted by the antenna assembly. At least one frequency selective RF power detector is coupled to one of the signals generated from one of the base transceiver stations for generating an output indicating whether the signal at a predetermined frequency is present. A logic control module is coupled to the frequency selective RF power detector for generating a control signal in response to the output of the detector. An oscillator is coupled to the logic control module for generating a carrier signal at the predetermined frequency for the combined signal in response to the control signal.

Abstract: There is disclosed an injection circuit for measuring radio frequency (RF) signals in an RF receiver for use in measuring the impedance match of a receive antenna and for use in calibrating receiver gain, wherein an advantageous embodiment of the injection circuit comprises: 1) a circulator coupled to the receive antenna; 2) a directional coupler coupled to the circulator; 3) an injection source coupled to the circulator and to the directional coupler, wherein the injection source is capable of injecting a test RF signal into either the circulator or the directional coupler; and 4) a terminating switch for selectively enabling or disabling the transfer of a test RF signal from the injection source to either the circulator or the directional coupler. The circulator has a reverse isolation of at least 20 dB that significantly increases the accuracy of the measurements of the RF signals compared with the accuracy that may be achieved by prior art methods.

Abstract: There is disclosed a signal monitoring apparatus for use in a wireless network base station containing a modular main unit for processing baseband signals and a modular radio unit separate from the main unit for transmitting and receiving radio frequency (RF) signals. The signal monitoring apparatus is disposed in the radio unit and monitors an RF output signal transmitted by a transceiver in the radio unit. The signal monitoring apparatus comprises an RF mixer that mixes the RF output signal and receiver local oscillator (LO) signal used by the receiver portion of the transceiver to demodulate received RF signals. The RF mixer generates an intermediate frequency (IF) signal capable of being transmitted through a communication line at relatively low signal loss to a signal measuring device located in the main unit or elsewhere.

Abstract: There is disclosed an injection circuit for measuring radio frequency (RF) signals in an RF receiver for use in measuring the W impedance match of a receive antenna and for use in calibrating c) receiver gain, wherein an advantageous embodiment of the injection circuit comprises: 1) a circulator coupled to the receive antenna; 2) a directional coupler coupled to the circulator; 3) an injection source coupled to the circulator and to the directional coupler, wherein the injection source is capable of injecting a test RF signal into either the circulator or the directional coupler; and 4) a terminating switch for selectively enabling or disabling the transfer of a test RF signal from the injection source to either the circulator or the directional coupler. The circulator has a reverse isolation of at least 20 dB that significantly increases the accuracy of the measurements of the RF signals compared with the accuracy that may be achieved by prior art methods.

Abstract: There is disclosed a system for tuning a tunable narrowband cavity filter in a base station transmitter of a wireless network. The radio frequency (RF) transmitter comprises: 1) modulation circuitry for modulating an input baseband signal to produce a first RF signal; 2) amplification circuitry for amplifying the first RF signal; 3) a tunable narrowband cavity filter for filtering the amplified first RF signal and transmitting the filtered and amplified first RF signal to an antenna coupled to an output of the tunable narrowband cavity filter; and 4) a system for tuning the tunable narrowband cavity filter.

Abstract: There is disclosed a system for determining the impedance match of an antenna, for use in an RF transceiver comprising an RF transmit path comprising circuitry capable of amplifying an RF signal and transmitting the amplified RF signal to the antenna coupled to the RF transceiver. The system comprises: 1) a test signal generator coupled to the RF transmit path for generating a first test signal and injecting the first test signal into the RF transmit path, wherein the RF transmit path amplifies the first test signal; 2) an RF mixer coupled to an output of the RF transmit path for down-converting the amplified first test signal to produce a second test signal at a frequency within a receive frequency band of the RF transceiver; 3) an RF coupler coupled to an output of the RF mixer for transmitting the second test signal into the antenna and for receiving a reflection of the second test signal; and 4) a first signal monitor coupled to the RF coupler for measuring the reflection of the second test signal.

Abstract: There is disclosed an injection circuit for measuring radio frequency (RF) signals in an RF receiver for use in measuring the impedance match of a receive antenna and for use in calibrating receiver gain, wherein an advantageous embodiment of the injection circuit comprises: 1) a circulator coupled to the receive antenna; 2) a directional coupler coupled to the circulator; 3) an injection source coupled to the circulator and to the directional coupler, wherein the injection source is capable of injecting a test RF signal into either the circulator or the directional coupler; and 4) a terminating switch for selectively enabling or disabling the transfer of a test RF signal from the injection source to either the circulator or the directional coupler. The circulator has a reverse isolation of at least 20 dB that significantly increases the accuracy of the measurements of the RF signals compared with the accuracy that may be achieved by prior art methods.

Abstract: A measurement and calibration circuit is disclosed for use in a RF transceiver comprising an antenna and a RF receiver, having a receive path, coupled to the antenna. The measurement and calibration circuit comprises: a test signal generator for generating a known amplitude and frequency test signal; a switch having an input coupled to the test signal generator, a first output coupled to an input of the receive path, and a second output coupled to the antenna; a test controller for causing the switch to directly inject the test signal into the input of the receive path and causing the switch to inject the test signal into the antenna, wherein the antenna at least partially reflects the test signal into the receive path; and a signal monitor coupled to an output of the receive path for measuring the direct injected test signal and the reflected test signal.

Abstract: There is disclosed a test apparatus for use in a wireless network base station comprising a non-radio unit for processing baseband signals and a radio unit separate from the non-radio unit for transmitting and receiving radio frequency (RF) signals. The test apparatus comprises: 1) a housing; 2) a first connector coupled via a first cable to the radio unit, wherein the first cable comprises signal lines carrying base station signals between the radio unit and the non-radio unit; 3) a second connector coupled via a second cable to the non-radio unit, wherein the second cable comprises signal lines carrying the base station signals between the radio unit and the non-radio unit; and 4) a first access connector that allows a signal measuring device to monitor at least one of the base station signals.

Abstract: There is disclosed a power control circuit for controlling the combined effective DC bias current of a bank of parallel RF power amplifiers disposed in the transmit path of an RF transmitter. The power control circuit comprises: 1) a first signal monitor for monitoring the level of a modulated RF output signal; and 2) an amplifier bias current controller for comparing the modulated RF output signal level and a known maximum output power parameter of the active RF power amplifiers to determine if the active RF power amplifiers are operating in the linear region. If the active RF power amplifiers are operating in or near the nonlinear region, the power control circuit enables one or more inactive RF power amplifiers to increase the effective combined DC bias current and linearity of the active RF power amplifiers.