A system and method for automatically generating a return beam in the direction of a received beam. The inventive system (10) includes a phased array antenna (12) for receiving a radio frequency signal having a first wavefront from a first direction. In response to this signal, the invention (10) provides a second signal having a second wavefront. The second signal is a phase conjugate of the first signal and is transmitted in a reverse direction relative to the direction of the first signal. In the illustrative embodiment, the invention includes a plurality of phase conjugators each of which are disposed in a transmit/receive module and coupled to an associated radiating element. Each of the phase conjugators includes a mixer (60) having the input signal as a first input thereto. The input signal has a first frequency and a first phase. A second signal having a frequency equal to twice the first frequency is input to each mixer (60) from a reference frequency module (30) such that the output of the mixer includes a component representative of the negative of the first phase. The output of each mixer (60) is filtered to extract a signal component having a negative phase relative to the input signal. These signal components are then transmitted as the phase conjugated wavefront. This process will occur for each signal when multiple signals are received within the field of regard of the phased array antenna (12).

A system and method for controlling power transferred to an aircraft. The system includes a master antenna and a plurality of slave antennas on the ground. Each slave antenna transmits an uplink signal of a unique phase modulated frequency. The master antenna transmits a master uplink signal. The aircraft receives all the uplink signals and modulates a composite of those signals to produce a downlink beacon that has multiple phase components, each of which corresponds to one of the slave antennas and has a unique frequency. Each of the slave antennas receives the downlink beacon and uses the corresponding phase component to adjust the phase of the slave uplink signal relative to the master uplink signal.

A radio frequency transponder/repeater is provided wherein an array of receiving antenna elements is coupled to an array of transmitting antenna elements to provide a directional antenna system and including additionally an internal radio frequency source which is also coupled to the array of transmitting antenna elements. With such arrangement, an internally generated signal provided by the radio frequency source may be transmitted using the transmitting array of the Van Atta System.

The present invention relates to a T.V. tuner cassette insertable into a tape player. These tape players (or recorders) normally have magnetic pick-up heads, volume controls and other signal conditioning circuitry which collect and modify an audio signal prior to application of the audio signal to one or more speakers. The T.V. tuner cassette demodulates the audio components of the received T.V. signal and applies the demodulated audio component to the electronic circuitry in the tape player by an inductive or an electromagnetic link established with the magnetic pick-up head in the tape player and an inductive transmitter in the T.V. tuner cassette. The T.V. tuner cassette is powered from a power cable extending beyond or outboard of the tape player. The power cable, at its remote end, terminates in a cigarette lighter adapter plug. This plug fits into a standard cigarette lighter outlet. Mounted on the cigarette lighter adapter plug is a tuner control such that a user can select a T.V. broadcast signals by actuating or rotating the tuner control. In addition, the power cord may include or carry an antenna for the T.V. tuner cassette. A method of detecting and reproducing the audio component of a T.V. signal is also included.

Apparatus and method for determining velocity and range of a target within a field of view. A velocimeter and tracker (10, 100) includes a laser (12, 12') that produces modulated coherent light, a portion of which illuminates targets (22, 22') coming into a field of view (24, 24') of the velocimeter and tracker. Coherent light reflected from the target travels back along a detection path toward a phase conjugate mirror (40, 40') as a probe wave (26, 26'). A higher intensity portion of the coherent light produced by the laser is split into equal parts that are directed toward the phase conjugate mirror from opposite directions and interact with the probe wave to produce a phase conjugate light signal that travels back along the detection path and is also reflected from the target. Light reflected by the target experiences a Doppler phase shift as a function of target velocity. First, second, and higher order phase shifted signals reflected from the target are imaged on photo diodes (68, 68'), producing an electrical signal having components corresponding to the frequency differences of the various order light signals. As a function of the sums and differences of the frequency components of the electrical signal, the range and velocity of the target are determined.