Abstract: A processing circuit (50) in a communication system performs multi-channel adaptive array processing using a summed reference technique. A plurality of adaptive modules (56 and 58) modify the magnitude and phase of antenna element signals from a plurality of antenna elements. The outputs of the adaptive modules are combined by a combiner (60) to produce a summation signal. A modem (64) processes and divides the summation signal into a plurality of reference channel signals on channels 1 through K. A summer (70) adds the reference channel signals together to produce a composite reference signal that is subtracted by a subtractor (74) from the summation signal to produce an error signal. The error signal is applied to the adaptive modules (56 and 58) which respond to nullify interfering and noise signals and to enhance the signal-to-interference ratio for the summation signal.

Abstract: A surface acoustic wave variable time delay includes a surface acoustic wave device (10) which is secured within a housing (30). The device (10) is provided with an input transducer (12) and an output transducer (16) which are respectfully connected to input lines (14) and output lines (18). An electrostrictive element (20) is secured within housing (30) between an end of device (10) and an interior wall (34) of housing (30). A control signal is applied to electrodes (22, 24) connected to element (20) to vary the size thereof. Element (20) applies a mechanical force to the surface acoustic wave device (10) to alter the distance between the input transducer (12) and output transducer (16) to thereby control the delay time between the signal supplied to the input lines (14) and the output signal at the output lines (18).

Abstract: A continuously variable delay line (10) includes a piezoelectric crystal (12) having an input transducer (14) and an output transducer (16). An input signal is transmitted through input lines (18) to the input transducer (14) and received through output lines (20) from the output transducer (16). The input signal is converted to a surface acoustic wave for transmission across the surface of crystal (12). Control electrodes (22 and 24) are applied to surfaces of the crystal (12) and are connected to control lines (26). A control signal is applied to the control lines (26) to apply an electric field to the crystal (12). The electric field thus applied alters the longitudinal dimensional characteristic of the crystal (12) and thereby controls the propagation distance between the input transducer (14) and the output transducer (16).