John M. Zomp

Hybrid electronic fiber optic wavelength-multiplexed system for true time delay steering of phased array antennas

A hybrid electronic fiber optic true time-delay steering architecture is presented which retains the highly hardware compressive property of an earlier all-optical approach and introduces the economical advantages of electronics at every level possible without compromising overall performance. The architecture is particularly suited to large arrays where maximum advantage can be taken of the hardware compression. A detailed design based on this architecture is described for steering a linear, 16-element, L -band (0.7- to 1.4-GHz) array in transmit mode over a scan angle of ±20 deg with a delay resolution of 6 bits (0.63 deg). An analysis of the expected performance of the design is given together with progress toward the fabrication of the prototype system, which includes the first iteration electronic binary delay line subsystem and a single-segment, high-fidelity, directly modulated DFB laser diode fiber optic link. The experimental data from these modules is in agreement with the performance predicted from the analysis.

Development and field demonstration of a hardware-compressive fiber-optic true-time-delay steering system for phased-array antennas

We describe the design, fabrication, testing, and antenna-range demonstration of a photonic wavelengthmultiplexed true-time-delay steering system for use with broadband phased-array antennas. The prototype system is based on a unique hardware-compressive architecture and can drive 16 antenna elements over the 0.35-2.1-GHz band with 6-bit angular resolution over a ±45° scan angle.

Prototype Binary Fiber Optic Delay Line

The operation and features of an electronically switched, programmable binary fiber optic delay line are discussed. The design, component selection, fabrication, testing, and evaluation of a prototype are presented. The prototype comprises seven delay stages, has a maximum delay of 5µs and a resolution of 39 ns, operates over the 0.5 to 1 GHz band with a dynamic range of 36 dB, and has a power consumption of 19 W.

Development and field demonstration of an eight-element receive wavelength-multiplexed true-time-delay steering system

We describe the design and development of an eight-element hardware-compressive receive true-time-delay steering system that employs wavelength-division multiplexing. The laboratory system performance and results from the system demonstration at the antenna range are discussed.

Portable acoustic intensity measuring device

A portable acoustic intensity measuring device comprising a pair of electroacoustic transducers at a positioned predetermined distance from one another. The measuring device utilizes analog summing, subtraction, integration and multiplier means for measuring an acoustic intensity vector midway between the two electroacoustic transducers. The acoustic intensity measuring device further comprises error correction means connected in circuit with a preamplifier means and a meter means. The error correction means includes switching means comprising a first switch connected in circuit with the preamplifier and summing means and subtraction means and a second switch connected in circuit with the multiplier and the meter for simultaneously switching the first and second preamplified analog signals at the summing input and subtraction input and for simultaneously switching the polarity of the acoustic intensity signal at the meter. The error correction means eliminates any errors induced by phase mismatch and/or any inherent DC component of the device.

Stabilizing the radiant flux of a xenon arc lamp.

A closed loop feedback system for stabilizing the radiant flux of a xenon arc lamp is described. Stabilization is accomplished by focusing the image of the arc onto a photodiode, the current output of which is amplified and used to modulate the arc current in a dc controlled power supply. The feedback control eliminates light intensity spikes and drift and significantly reduces noise. The lamp characteristics (current, voltage, radiant flux) were recorded under controlled and uncontrolled operating conditions.

Development and antenna-range demonstration of an 8-element optically powered directly modulated receive fiber optic manifold

We describe the developemnt and antenna range demonstration of a UHF 8-element optically- powered directly modulated fiberoptic manifold. Active laser diode drive circuits are used to increase the laser diode sensitivity and reduce the link noise figure. The manifold operates over the 340-400 MHz band, it consumes low power (55 mA at 4 V per channel), has a two- tone dynamic range of 69 dB/MHz and a noise figure of 2.4 dB.

Development and demonstration of the Westinghouse hardware-compressive true time delay (TTD) fiber optic system

We describe the development and antenna range demonstration of the Westinghouse fiber optic wavelength-multiplexed true time delay steering system for use with broadband phased array antennas. The prototype system is based on a unique hardware compressive architecture and can drive 16 antenna elements over the 0.32 to 2.1 GHz band with 6-bit angular resolution over a +/- 45 degree(s) scan angle.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.