International Telephone and Telegraph Corporation

Other

Itt Gilfillan, a Division of Itt Corporation

Arnold M Levine

Ray O Waddoups

A radar system with auxiliary scanning provision for providing more dwell time on target, the system having a main frequency scan antenna with electronic or mechanical arrangements for auxiliary scanning. In the electronic embodiment, a space fed phased-array auxiliary antenna is provided, the radiating elements being interconnected with diode phase shifters, which are electronically actuated and synchronized to the antenna rotation. In the mechanical embodiment, a multi-sided prism arrangement in front of the antenna rotates in synchronism in a counter direction to the antenna, with auxiliary scanning data electronically manipulated for processing.

Radar system with auxiliary scanning for more dwell time on target

An electro-optical, motion picture, film sound track recording and playback system in which a complex audio signal wave is successively sampled and digitally encoded according to pulse-code modulation techniques (PCM) extant in the communications art. The digital codes are optically applied to the film sound track and are played back by optical detection as the film runs through a projector. The advantages of PCM signal-to-noise improvement are obtained, and means for the individual sample codes to be 'scrambled' on recording and 'unscrambled' on replay are shown. The scrambling greatly increases the difficulty of surreptitious copying by 'film pirates'. One embodiment shown applies and detects the individual code bits through individual optical fibers and the other applies and detects codes serially using a modulated laser source and a controllable refraction optical crystal or a Bragg Cell to scan across the sound track to emplace (and replay) individual sample codes.

Film sound track recording and playback system

A system including a frequency ramp generator feeding a transmitting power amplifier and antenna through a phase modulator and gain-controllable, transmitter driver stage. The frequency ramp generated is sampled out through a wide band delay-line feeding a phase comparator, the other comparison input to the phase comparator being provided by a sampling probe at the transmitting power amplifier output. The phase comparator output is used as a phase correction signal applied to the phase modulator and an amplitude modulation detector also responsive to the signal on the transmitting power amplifier output provides a feedback signal controlling the gain of the transmitter driver on a high bandwidth basis. Accordingly, instantaneous and long term frequency ramp phase and amplitude variations are substantially cancelled out so that the power amplified output is an accurate replica of the originally generated frequency ramp.

FM Transmitter with frequency ramp phase and amplitude correction means

Apparatus is shown for controlling pulse width in pulsed, step-wise frequency modulated transmitters employing relatively long pulse widths and receiving pulse compression. Also disclosed is a pulsed pseudo-random coded radar system having fixed code word duration. Individual solid-state, RF power amplifier modules are paralleled, all spares included, and the full parallel group is operated at a power level such that individual units operate substantially below maximum power rating. RF solid-state device life is thereby increased. Failures of individual solid-state modules are recognized by a power monitor which operates to lengthen the pulse width in the FM staircase embodiment and to increase power supply input and, therefore, peak pulse power in the pseudo-random coded embodiment, thereby restoring average nominal transmitter power, notwithstanding one or more failed solid-state RF amplifiers.

Automatic failure-resistant radar transmitter

A pulse compression radar which transmits a step-wise FM pulse and correlates at the receiver using a bank of delay lines (having progressively increasing delays) of the fiber optic type. One such delay line corresponds to each step of the frequency modulation program transmitted. The summed delay line outputs converted to electrical signals are summed to provide the compression desired. A suitably amplified stair-step received echo signal is applied to control the deflection of a Bragg cell illuminated from a laser source, the variable light ray deflection produced by the Bragg cell being focused progressively at the input of each of the discrete fiber optic delay lines. The same bank of fiber optic delay lines is employed in an oscillator loop, these delay lines being effectively electronically switched into place sequentially in the frequency determining feedback loop of the oscillator circuit. The same or a different laser source floods all inputs of the fiber optic delay lines through a light modulator in the feedback path, the desired stair-step FM transmitted signal being a modulation on the light energy employed in the oscillator configuration. Time-sharing transmit/receive and light source wavelength/color separation embodiments are shown.

Pulse frequency modulator and compressor for staircase FM radar systems

For aircraft equipped with ATCRBS and ILS, an identification and surface guidance system including a plurality of detection positions each including an interrogator and an auxiliary transponder located adjacent the runway and on opposite sides thereof, respectively. The interrogator is enabled through a signal cable from a remote location, such as a control tower, to produce the first of the discretely spaced pulse pair required to interrogate the ATCRBS equipment. The second interrogation pulse of the pair is generated by the transponder, which is activated by the radiated first pulse from the interrogator and includes an internal delay, such that this delay plus the transit time from the transponder serves to generate the second pulse of the pair if the aircraft to be interrogated is in the vicinity and on the pathway centerline or within a specified lateral tolerance therefrom. The ATCRBS reply may be received directly at the control tower or may be transmitted by cable from receiving equipment within the interrogator. ATCRBS decoding and display equipment may be employed at the control tower for discrete identification of a given aircraft. The identification points are distributed along a runway, taxiway or other surface area of an airport for continuing identification. Time discrimination apparatus compares the ATCRBS pulse train received by the transponder and retransmitted therefrom to the interrogator to that received directly by the interrogator to generate a signal representative of the aircraft deviation from pathway centerline, and this signal is transmitted on an unused ILS channel to the aircraft for presentation to the pilot on the localizer cross-pointer indicator within the aircraft.

Airport surface identification and control system

For aircraft equipped with ATCRBS, an interrogation system including an interrogator and an auxiliary transponder located adjacent the runway and on opposite sides thereof, respectively. The interrogator is enabled through a signal cable from a remote location, such as a control tower, to produce the first of the discretely spaced pulse pair required to interrogate the ATCRBS equipment. The second interrogation pulse of the pair is generated by the transponder, which is activated by the radiated first pulse from the interrogator and includes an internal delay, such that this delay plus the transit time from the transponder serves to generate the second pulse of the pair if the aircraft to be interrogated is in the vicinity and on the pathway centerline or within a specified lateral tolerance therefrom. The ATCRBS reply may be received directly at the control tower or may be transmitted by cable from receiving equipment within the interrogator. ATCRBS decoding and display equipment may be employed at the control tower for discrete identification of a given aircraft. The identification points may be distributed along a runway, taxiway or other surface area of an airport for continuing identification.

System for identification of aircraft on airport surface pathways

A pulsed radio-frequency transmitter-modulator system including circuits for converting a sample of the transmitter-radio frequency pulse to a corresponding video pulse and comparing this to the standardized timing pulse of the system to develop a control signal as a function of the leading edge delay and pulse duration of the RF pulse compared to the system timing pulse. The control signal is applied in a type of feedback loop including circuits responsive thereto for adjusting the pulse position and duration between the system timing pulse generator and the modulator of the pulse transmitter. The principal purpose is relief from the effects of temporal noise and the resulting improved performance of moving target indicator circuits associated therewith.

Radar transmitter temporal noise reduction system

A fiber optic delay line-controlled oscillator or tuned amplifier. Two embodiments are shown and described, one employing a single solid state active element and the other employing two such elements. The fiber optic delay line or lines employed are combined electronic-to-light transducer(s) supplying the delay line or lines and optical-to-electronic transducer(s) responsive to the optical delay line or lines output(s). That combination provides the tuned or oscillatory feedback path. In one embodiment, a plurality of delay lines are effectively switched into the circuit discretely and selectively in response to a staircase control function.

EMP Resistant oscillator with fiber optic frequency determining means

A frequency synthesizer or programmable multiple frequency source which uses a voltage-controlled oscillator (VCO) responsive to an independent control variable. The VCO is also responsive to control from an error loop circuit which derives an additional control voltage as a result of comparing the VCO frequency at any time with one of the phase delay multiples of a fiber optic delay line. The independent variable used to select an overall frequency desired controls the VCO directly to an approximate frequency and the fiber optic delay line and error generating loop associated therewith operates as an automatic vernier on the VCO to bring it into phase-lock with the nearest frequency which is a multiple of the reciprocal of the fiber optic line delay time.

Frequency synthesizer having frequency control loop including fiber

A system for providing the plural variable phase RF signals required to control the beam pointing angle of a phased array. A light energy source (shown as a laser generator) is modulated by an RF signal and fed to a plurality of channels in parallel. Each of the said channels corresponds to one radiating element of the phased array and each channel includes as many selectively employed fiber optic delay lines of different lengths as are required to generate the discrete phases required at the corresponding antenna (radiator) element of the array. A commutating programmer controls the selection of individual radiating element phases for each successive beam pointing position.

Fiber optic phased array antenna system for RF transmission

A system for providing secure communication by use of optical frequency transmission between an aircraft or spacecraft and a deeply submerged submarine. The submarine extends at least one fiber optic cable terminated in a lens arrangement. A flotation unit insures that the cable is extended substantially vertically to a point approaching, but not penetrating the surface of the sea. The thickness of the water layer between the surface and the cable upper end is thereby such as to reduce the attenuation of transmitted and received optical signals. Submarine communications may thereby be effected through modulated light beams while the submarine itself remains at a greater and more secure depth.

Submarine optical communication system with fiber optic depth compensator

An EMP resistant A/D converter having no triggered circuits, the digital code word being formed by sampling the analog function on a periodic basis, selectively quantizing the levels sampled into channels providing the digits of the output code through a discrete fiber optic delay medium for each digit in the output. Electronic to light conversion and vice versa are included.

Analog-to-digital converter with electro-optical coding

A system for detecting, monitoring the movements of, and controlling the travel of aircraft and other vehicles on an airport surface. A series of small low-powered radar transmit-receive devices, each having a limited range, is disposed essentially in a line along alternate and opposite sides of a runway, ramp or taxiway. Control pulses at a system PRF travelling down the inter-connecting cables serve to cause the individual radars to 'blink' in sequence in accordance with the inherent delay in the inter-connecting cable. Frequency separation is used to prevent false indications due to transmit-receive inter-action among the individual miniature radars. The system is adapted to data presentation in accordance with standard radar display techniques, or alternatively, a display is provided on a synthesized map of the airport. A pulse delay discriminator arrangement provides for discrete lateral position control. Means are also shown for televising the ground display to a vehicle on the surface and for providing discrete information such as a STOP order, etc.

Growing community of inventors

Chatsworth, CA, United States of America

Arnold M Levine