Abstract: A signal processing apparatus for providing electrical frequency measurements of input signals. In one embodiment, a power splitter divides an RF input signal into first and second input signals. An RF channelizer having a filter bank receives the first input signal and determines a coarse frequency measurement. An optical modulator modulates an optical carrier signal with the second input signal, and a beam splitter divides the modulated carrier signal into a plurality of optical signals that each feed into one of a plurality of optical frequency discriminators (“OFD”). Each OFD uses a fiber optic delay line and spatial domain sampling techniques to extract a phase measurement. An ambiguity resolver receives the phase measurement from each OFD and determines a single, absolute phase measurement, which is translated to a fine frequency measurement. A frequency encoder combines the coarse and fine frequency measurements to produce a final frequency measurement having increased resolution.

Abstract: A peripheral device isolator (32) is provided which consists of an insulating material (33) having a first conductive area (34) on a top surface and a second conductive area (35) on a bottom surface. A transient voltage suppressor (36) provides an electrical connection between the first conductive area (34) and second conductive area (35) through a first lead (38) and a second lead (40). When the peripheral device isolator (32) is placed between an internal peripheral device (12), having a common logic and chassis ground, and a host frame (10), having a host system frame ground (16), an electrical path for a voltage spike occurring on the internal peripheral device (12) is provided so that the voltage spike can be diverted away from host system logic ground (22) and into host system frame/safety ground (16).

Abstract: The extraction of phase information for radio frequency (RF) direction of rival is attained by pre-detect sensing and quantization of differential phase of a RF wave impinging on two or more antenna apertures, based on sensing and encoding differential phase without the use of conventional detection, and quantizing phase at or near the leading edge of a pulse signal. This is accomplished by detection of an intermediate frequency (IF) carrier, and encoding leading-edge phase (for each channel) in terms of near-phase-difference between two reference-oscillator readings containing the differential phase information--encoded as differential reference-oscillator phase. Precision angle-of-arrival is then derived from the measured differential reference-oscillator phase.