US Government As Represented by the Secretary of the Army

Charles E Konig

William J Skudera, Jr

This disclosure relates to a circuit for detecting the phase transitions in a PSK signal in the presence of a stronger CW signal. A SAW transform circuit carries out 'piecewise' Chirp-Z transformations of the PSK and CW signals so as to achieve a separation of the same in the time domain. A gate and a pulse width discriminator are both coupled to the output of the Chirp-Z transform circuit. The discriminator rejects all signals except the transformed phase transitions of the PSK signal. The output of the discriminator is utilized to periodically enable the gate for short durations (e.g., 2nsec.) to selectively pass the transformed PSK signal including transformed phase transitions thereof. The gated output is delivered to a dual channel SAW differential delay line whose two channels are of different lengths to provide a predetermined amount of delay (t) therebetween (t.ltoreq.PSK bit duration). A comparator serves to compare the output signals of said two channels and when they differ it produces an output pulse. A counter serves to count the output pulses from the comparator.

Transition detection circuit for PSK signals using the SAW Chirp-Z

BPSK signals are detected by receiving an input signal containing the BPSK ignals to be detected, by means of a compressive receiver; applying the receiver output to a 90.degree. phase shifter which outputs a phase-shifted signal; applying the phase-shifted signal to a delay line which applies a further phase shift of -180.degree. to the phase shifted signal; and detecting the relative phase of the non-phase-shifted signal from the compressive receiver and the phase-shifted signal from the delay line by applying those signals to respective input ports of a phase detector, the output of the phase detector being indicative of detection of a BPSK signal. Advantageously, zero-crossings of the output signal of the phase detector are detected, and the output of the zero-crossing detector is low-pass-filtered.

Detection and characterization of LPI signals

An FH interceptor for determining bandwidth, hop number, dwell time, hop e, channel spacing and hop frequencies. A compressive receiver, having a passband greater than the bandwidth, samples received signals at a scan rate greater than the hop rate. On each scan, the receiver separates the received signal into its frequency components. A histogram memory, connected to the receiver, stores a frequency distribution of the frequency components including the scan periods. A data processor uses the histogram memory to determine the FH parameters.

Frequency hopping signal interceptor

An array of fiber optic RF filters each responsive to a predetermined wavngth forms a channelizer for a wide bandwidth receiver used in a dense signal environment having complex modulations. Each fiber optic RF filter comprises a resonant cavity formed from a section of multimode optic fiber with a dielectric mirror deposited at each end and wherein the cavity length corresponds to one half the respective modulation signal wavelength of optical energy fed into the filter optic cavity from a laser diode which is modulated by the received RF energy.

Fiber optic RF signal channelizer

A plurality of acoustic charge transport (ACT) tapped delay lines are coupled to respective antenna elements of a phased array antenna assembly to control the beam steering of either a transmitted or received electromagnetic wave in the megahertz (MHz) range. Each delay line, moreover, is comprised of an ACT channel region which operates as a delay line and further includes multiple signal output taps which can be selectively addressed from an address bus coupled to a digital controller for providing a predetermined delay. With each delay line being individually controlled, an improved technique for beam steering is provided.

Non-dispersive acoustic transport time delay beam steering antenna

Wide band and narrow band Chirp-Z channels are interfaced to enhance signal nalysis resolution for the signal's individual component wave forms over a wide signal bandwidth. The frequency characteristic of a selected component wave form is matched to the sweeping local oscillator and filter frequency parameters of the narrow band channel in accordance with the relative position occupied by the frequency characteristic of the selected component wave form in the frequency segregated time domain of said wide band channel. In one preferred embodiment, a mixer and a voltage controlled oscillator are utilized to accomplish the frequency matching and in another embodiment, a band-pass filter precisely defines the bandwidth of the selected component wave form. For still another embodiment, the voltage input to the voltage control oscillator is controlled in accordance with the difference in frequency between the selected component wave form and said narrow band channel.

High resolution, wide band Chirp-Z signal analyzer

A phase transition detector for PSK signals which utilizes a dual channel SAW differential delay line to achieve a required delay. Each channel or path of the SAW device comprises an input and an output transducer. The two channels provide a predetermined differential delay (T) inasmuch as they are of different lengths. A PSK input signal is delivered to a power splitter, with the output therefrom coupled to the pair of input transducers of the SAW device. The output transducers are coupled to a multiplier which serves to detect phase transitions in the input PSK signal. The multiplier output is coupled to an output terminal via a low pass filter which provides harmonic repression. In another embodiment a SAW device comprises a bank of dual channel differential delay lines with each dual channel set to a different predetermined delay (T) so that a plurality of PSK signals of different chip rates can be separated out and detected. The PSK input signals are delivered to a power splitter, with the output therefrom coupled to a pair of input transducers of the SAW device. Output transducers are spaced predetermined distances from one or the other of said input transducers. Parallel sets of multipliers and low pass filters are coupled to predetermined SAW output transducers. Each multiplier serves to detect the phase transitions in one, and only one, PSK input signal. The input transducer(s) can be placed near the center of the SAW device, with the output transducers placed on the same, or either, side of the input transducer(s).

Saw transition detector for PSK signals

An apparatus is disclosed which permits a high speed waveform, for example n the form of a series of analog data pulses, to be sampled and converted into a series of digital values. Each analog data pulse is applied in parallel to a multiplicity of A/D converters and to one or more level detectors. Each level detector provides a strobe when the voltage of the analog data pulse crosses a reference threshold. The strobes are applied to delay means whose outputs are a multiplicity of delayed strobe pulses which have been delayed by predetermined amounts. Each of the multiplicity of delayed strobes is applied, along with the analog data pulse, to one of the multiplicity of A/D converters. Each of the multiplicity of A/D converters samples the analog data pulse in response to the particular delayed strobe applied thereto and provides a digital value of that sample. The largest of the digital values from each of the A/D converters is provided as the output of the apparatus for each analog data pulse.

Growing community of inventors

Staten Island, NY, United States of America

Charles E Konig