Abstract: A solid state remote monitoring transmitter which transmits a 40 bit word that contains status information about a transformer via the secondary of a power distribution network to a central receiver associated with the primary (feeder) cable supplying the transformer. A program card specifies the carrier signal frequency and the identification of the transmitter. Multiple ananlog inputs are switched through a multiplexer to an A/D converter, the output of which is stored in a shift register to form the 40-bit word. The word is DPSK - coded by clock pulses in synchronism to the 60 Hz zero crossings of the AC power source and amplified by an unregulated power supply which is also powered by the AC power source. The phase transitions of the DPSK - coded word occur at the zero crossings diminishing any transients in the transmitter circuitry which would be caused by the phase transitions.

Abstract: Video information from scanned separations is stored on a video tape recorder (VTR) after processing and formating. Video information stored on the tape of the VTR may be input into the memory of a separations previewer after decoding and processing. A controller controls the operation of switches which route the information and the VTR. A keyboard, control panel and printer interface with the controller.

Abstract: A stereo speaker system is shown having at least three individual speakers arranged along a path, with one of the speakers positioned between the other two speakers and connected to receive signals from a selected one of a pair of left and right signal outputs from a stereo signal source such as a stereo radio. Both of the other two speakers are connected to receive signals from the remaining one of said pair of outputs. Balanced stereo images are thus obtained simultaneously at two different locations. The system has particular application in an automobile. Another embodiment is shown which uses more than three speakers.

Abstract: In a system having plural signal-carrying channels, a phase shift is introduced between a signal in one of the channels and a reference signal for calibrating the individual channels. The phase shift is introduced by phase-shift apparatus responsive to a command signal directing the continuous monotonic increment of phase. The apparatus may be contained within each channel for use in the signal-carrying process, or may be placed in the reference channel for use solely in the calibration process. The phase incrementing introduces a frequency shift (a serrodyning) which produces a beat-frequency signal upon mixing a channel signal with a reference signal. The beat-frequency signal is phase locked to a modulation pattern of the command signal whereby a measurement of phase (or delay) can be made between the two signals for calibration of each channel within the system.

Abstract: An apparatus for cancelling undesired signals affecting an antenna system. The apparatus includes a plurality of adaptive modules. Each module provides sum and difference signals from a pair of antennas in the system. Each difference signal is weighted by an adaptive controller coupled to the difference signal and the apparatus output signal. All sum signals from the modules are sum and all weighted difference signals from modules are summed and the total weighted difference signal is subtracted from the total sum signal to provide an apparatus output. The adaptive controller is a multiplexer associated with each of the difference signals of the modules, a reference receiver receiving a multiplexed information and a correlator coupled to the received information and the apparatus output. The correlator controls the weights affecting each of the difference signals of each module. The output of the subtractor is decoded by a main receiver.

Abstract: An ink usage estimator signal is developed representing the amount of ink required to print on a receptive media a portion of an image which is on film, such as a color separation. A video signal representing the portion of the selected image is gated by area pulses during periods of the video signal which define the selected portion of the image. The gated video signal is averaged to develop the ink usage estimator signal, which represents the amount of ink required to print the selected portion of the image.

Abstract: A classical differential amplifier provides outputs of unequal magnitude due to its emitter resistance being finite. In order to equalize its output, a voltage follower circuit is associated with each of the inputs of the differential amplifier. The output of each voltage follower circuit is converted to a current and subtracted from one of the outputs of the differential amplifier. Subtracting the outputs results in a differential amplifier with both outputs being substantially equal.

Abstract: An oscillator having sufficient accuracy and precision for use in aircraft microwave-landing systems is constructed without the use of an external inductor. A resonant tank circuit comprising both capacitance and inductance is attained by the use of inductance found internally in the base-emitter junction of a transistor suitably biased for operation at the frequencies of a microwave landing system. A transistor having greater-than-unity gain in the oscillation-frequency range is selected for which the angle of the reflection coefficient of the base-emitter junction is positive in the oscillation-frequency range.

Abstract: A receiver for receiving recurring first and second scanning signals. The peak of successive first and second scanning signals is digitally detected and averaged. The gain of an amplifier of the receiver is controlled in response to the averaged peaks to anticipate the magnitude of the next scanning signal. As a result, recurring first and second scanning signals of significantly different magnitudes are received and processed by the receiver.

Abstract: Sheet metal having an opening therein includes projections adjacent to the opening. A column to be mounted at the opening has a slot therein for engaging the projections. The column has a threaded axial opening which is engaged by a screw located within the opening of the sheet metal. The opening may have a tapered portion with the projections located thereon.A tool for shaping the sheet metal with an opening therein is also disclosed. The tool includes a member having a first end to which a force may be applied and a second end with at least one radial projection. A seat is provided for receiving the second end of the member. The sheet metal is shaped by placing the opening over the seat, locating the second end of the member within the opening and sheet and applying a force to the first end of the member.

Abstract: In a receiver for composite amplitude and angle modulated signals and having a non-flat automatic gain control characteristic, there is provided apparatus for providing distortion correction to the quadrature component produced by the angular modulation in accordance with the amplitude modulation component. In accordance with the invention, the output of an amplitude demodulator is modified to remove the carrier signal level dependent magnitude multiplier and develop a modification signal which is used to inversely amplitude modulate the quadrature signal component to provide distortion correction over a range of carrier signal levels. Such inverse modulation can be provided before or after quadrature demodulation of the received signal.

Abstract: Coherent light is incident upon an acousto-optical cell through which bulk acoustic waves are propagating. These acoustic waves correspond to a signal to be detected and cause periodic variations in the refractive index of the cell which interact with the coherent light. Acoustic frequency components of the propagating waves cause the cell to diffract beams of incident coherent light in a unique direction and to frequency shift each beam of diffracted light. The relative phases of the acoustic frequency components are also imparted to the respective diffracted light beams. Diffracted and undiffracted coherent light beams are recombined so that optical heterodyning takes place. The recombined light beams are focused by a Fourier Transform lens onto a photomixer which detects the frequency difference between the diffracted and undiffracted light beams.

Abstract: Coherent light is incident upon an acousto-optical cell through which bulk acoustic waves are propagating. These acoustic waves correspond to a signal to be detected and cause periodic variations in the refractive index of the cell which interact with the coherent light. Acoustic frequency components of the propagating waves cause the cell to diffract beams of incident coherent light in a unique direction and to frequency shift each beam of diffracted light. The relative phases of the acoustic frequency components are also imparted to the respective diffracted light beams. Diffracted and undiffracted coherent light beams are recombined so that optical heterodyning takes place. The recombined light beams are focused by a Fourier Transform lens onto a photomixer which detects the frequency difference between the diffracted and undiffracted light beams.

Abstract: Apparatus for translating the position of a coherent beam of light using one or more acousto-optical cells. The beam is incident upon an acousto-optical cell through which acoustic waves of a selected frequency are propagating. These acoustic waves cause periodic variations in the refractive index of the cell which act to diffract and frequency shift the beam by amounts which are determined by the frequency of the acoustic wave. The once-diffracted beam is reflected back through the acosto-optical cell in the opposite direction, which causes a diffraction and frequency shift which are equal and opposite to the initial diffraction and frequency shift. By varying the frequency of the propagating waves, the final output beam of coherent light can be translated without a frequency shift. Also disclosed are a dual, identical Bragg cell embodiment for translating a light beam and dual Bragg cells having differing acoustic propagation velocities for deflecting a light beam.

Abstract: A printed circuit board includes first and second antenna elements spaced less than one-quarter wavelength apart and preferably one-eighth wavelength apart. Matching circuitry printed on the circuit board connects the elements to a quadrature coupler. The circuit board is foam encased in a blade-shaped fiberglass radome. The antenna radiates two independent null-free patterns.

Abstract: Analog video information with a wide range of radar characteristics is converted by a digital scan converter into a standard TV format. The analog video information is converted to digital PPI data and stored in a buffer. The digital PPI data is consecutively integrated on a pulse to pulse basis to eliminate noise. The digital PPI data is then stored in an image memory (RAM). The polar coordinates of each digital PPI data sample are converted to an address of equivalent X, Y coordinates wherein each point along a TV line is an X coordinate and each TV line is a Y coordinate. This address defines the location at which the data is stored in the RAM. Each address of X, Y coordinates uniquely defines a cell in the RAM which is three bits deep, describing eight intensity levels. Data is read from the image memory in time sequence with a TV synchronization signal for display on a TV monitor.

Abstract: A reflective tunnel of rectangular cross-section with opposing parallel or converging, opposing sides has a light diffuser located at the output opening of the tunnel for integrating the light passing therethrough and a densitometer located near the input opening of the tunnel for measuring the composition of the light within the tunnel. A lamp is positioned at the inner focal point of each of a plurality of dichroic elliptical reflectors which are supported at the input opening of the tunnel so that light emitted by each lamp is projected into the tunnel directly toward the light diffuser. The lamps are symmetrically disposed about the optical axis of the reflective tunnel and the reflector axes intersect the axis of the reflective tunnel at a point which is located between the midpoint of the reflective tunnel and the output of the tunnel.

Abstract: Multiple low frequency tones are employed for stereo indication in an AM stereo radio system. The tones are modulated on a carrier wave which is also multiplex modulated by stereo related audio signals. Detection of the presence of one of the tones in a received signal provides an indication of the possibility of stereo related modulation components in the received signal. Detection of the presence of both tones in the received signal provides confirmation that stereo related modulation components are in the received signal. In a preferred embodiment, 15 Hz and 30 Hz phase-related tones are used. A stereo receiver incorporates 15 Hz and 30 Hz phase detectors which form interrelated phase-locked loops with a 30 Hz reference oscillator. The presence of both tones in the proper phase relationship indicates reception from an AM radio station which is broadcasting in stereo.

Abstract: Coherent light is incident upon an acousto-optical cell through which bulk acoustic waves are propagating. These acoustic waves correspond to a signal to be delayed and result from the application of the signal to a piezoelectric transducer of the cell. The waves cause periodic variations in the refractive index of the cell which interact with the coherent light. Acoustic frequency components of the propagating waves correspond to the signal frequency components and cause the cell to diffract the beam of incident coherent light and to frequency shift the diffracted beam. The relative phases of the acoustic frequency components of the acoustic waves also correspond to the phases of the frequency components of the signal to be delayed and are imparted to the respective diffracted light beams. The diffracted light is combined with undiffracted coherent light so that optical heterodyning takes place.