Abstract: A transmit/receive switching circuit is provided. The transmit/receive switching circuit comprises a first transformer to split a transmission signal into a first split transmission signal and a second split transmission signal. The first split transmission signal is out of phase with the second split transmission signal. The transmit/receive switching circuit also comprises a second transformer to split a received signal into a first split received signal and a second split received signal and to combine the first split transmission signal and the second split transmission signal. The first split received signal is out of phase with the second split received signal. The combined transmission signal is supplied to an antenna port and the received signal is received from the antenna port.

Abstract: A method of compensating for component errors within a radar altimeter is described. The method includes periodically switching transmit pulses from a transmit antenna to a programmable delay device, calculating an altitude based on a transmit pulse received from the programmable delay device, comparing the calculated altitude to an expected altitude, the expected altitude based on a pre-set delay through the programmable delay device, and compensating an altitude measured by the radar altimeter, based on transmit pulses output through the transmit antenna, by an error correction amount based on a difference between the calculated altitude and expected altitudes.

Abstract: A transmit/receive switching circuit is provided. The transmit/receive switching circuit comprises a first transformer to split a transmission signal into a first split transmission signal and a second split transmission signal. The first split transmission signal is out of phase with the second split transmission signal. The transmit/receive switching circuit also comprises a second transformer to split a received signal into a first split received signal and a second split received signal and to combine the first split transmission signal and the second split transmission signal. The first split received signal is out of phase with the second split received signal. The combined transmission signal is supplied to an antenna port and the received signal is received from the antenna port.

Abstract: Ring laser gyroscope that includes a gyroscope block, a radio frequency transmitting device, and a radio frequency energy source. The gyroscope block has at least one discharge bore containing a gain medium, and the radio frequency transmitting device is located within the gyroscope block in proximity to at least one discharge bore and located so as to encompass the discharge bore. The radio frequency energy source is configured to apply a pulsed radio frequency signal to the transmitting device.

Abstract: A method for controlling a frequency output of a phase locked loop (PLL) is provided. The method includes providing digital control words to the PLL to discretely change at least one dividing factor within the PLL. The method further includes applying a time-varying control voltage to a voltage controlled oscillator. The method still further includes applying an output of the voltage controlled oscillator to the PLL as a reference frequency. The method further includes outputting a signal from the PLL, the signal varied in frequency based on one or more of the time-varying control voltage and the at least one dividing factor.

Abstract: A method of compensating for component errors within a radar altimeter is described. The method includes periodically switching transmit pulses from a transmit antenna to a programmable delay device, calculating an altitude based on a transmit pulse received from the programmable delay device, comparing the calculated altitude to an expected altitude, the expected altitude based on a pre-set delay through the programmable delay device, and compensating an altitude measured by the radar altimeter, based on transmit pulses output through the transmit antenna, by an error correction amount based on a difference between the calculated altitude and expected altitudes.

Abstract: In one aspect, a method of radar altimeter operation including a time dependent gain control is described. The method comprises triggering a Sensitivity Time Control (STC) gain control signal at a pulse repetition frequency (PRF) of a transmit pulse to attenuate interference from at least one of an antenna leakage signal and a signal reflected from equipment. The method also includes shaping the STC gain control signal from no attenuation at a first time, before a transmitter sends the transmit pulse, to a stable maximum attenuation at the time the transmitter sends the transmit pulse, to no attenuation at a second time, after the transmitter sends the transmit pulse. The method also includes matching a bandwidth of an intermediate frequency (IF) amplifier to the pulse width of a transmitted pulse.

Abstract: In one aspect, a method of radar altimeter operation, the altimeter including a high frequency counter coupled to a processor is described. The method comprises providing a continuous wave to the high frequency counter upon receipt of a transmit pulse, counting the cycles of the continuous wave, discontinuing counting of the continuous wave cycles upon receipt of a return pulse, outputting a count from the high frequency counter to the processor, and operating the processor to convert the count to an altitude.

Abstract: A method of delaying propagation of a radio frequency (RF) signal through a circuit is described. The method comprises receiving data that represents a delay time interval, providing an RF signal when a start pulse triggers a memory device, initiating a count through the delay time interval based on receipt of a start pulse, and outputting the RF signal after the delay time interval has expired.

Abstract: A method for phase calibrating antennas in a radar system is disclosed. The method comprises providing a transmit antenna and two or more receive antennas, the receive antennas each in communication with a respective receiver channel. A radio frequency pulse having a leakage pulse is transmitted from the transmit antenna. The leakage pulse is received at each of the receive antennas and respective receiver channel. The relative phase change between the receive antennas is determined by using the leakage pulse as a reference signal.

Abstract: In one aspect, a method of radar altimeter operation including a time dependent gain control is described. The method comprises triggering a Sensitivity Time Control (STC) gain control signal at a pulse repetition frequency (PRF) of a transmit pulse to attenuate interference from at least one of an antenna leakage signal and a signal reflected from equipment. The method also includes shaping the STC gain control signal from no attenuation at a first time, before a transmitter sends the transmit pulse, to a stable maximum attenuation at the time the transmitter sends the transmit pulse, to no attenuation at a second time, after the transmitter sends the transmit pulse. The method also includes matching a bandwidth of an intermediate frequency (IF) amplifier to the pulse width of a transmitted pulse.

Abstract: A method of delaying propagation of a radio frequency (RF) signal through a circuit is described. The method comprises receiving data that represents a delay time interval, providing an RF signal when a start pulse triggers a memory device, initiating a count through the delay time interval based on receipt of a start pulse, and outputting the RF signal after the delay time interval has expired.

Abstract: A method for phase calibrating antennas in a radar system is disclosed. The method comprises providing a transmit antenna and two or more receive antennas, the receive antennas each in communication with a respective receiver channel. A radio frequency pulse having a leakage pulse is transmitted from the transmit antenna. The leakage pulse is received at each of the receive antennas and respective receiver channel. The relative phase change between the receive antennas is determined by using the leakage pulse as a reference signal.

Abstract: A method for controlling a frequency output of a phase locked loop (PLL) is provided. The method includes providing digital control words to the PLL to discretely change at least one dividing factor within the PLL. The method further includes applying a time-varying control voltage to a voltage controlled oscillator. The method still further includes applying an output of the voltage controlled oscillator to the PLL as a reference frequency. The method further includes outputting a signal from the PLL, the signal varied in frequency based on one or more of the time-varying control voltage and the at least one dividing factor.