Abstract:
A central station including a computer is connected via a multichannel CATV cable to a plurality of remote terminal stations. Some of the channels are reserved for commercial television programs. However, a predetermined number of forward television channels are reserved for private television programs which may be generated either at the central station and transmitted on these forward channels to selected terminal stations under the control of the computer, or else a private TV program may be originated at one of the remote terminals, transmitted via the cable on a return television channel thereof to the central station, and then retransmitted from the central station via the cable on a forward television channel thereof to selected remote terminal stations under the control of the computer. Each terminal station contains an audio input means, such as a microphone and an audio transmitter, for permitting a return audio or speech signal to be inserted at the central station upon the audio subcarrier of television signal which is being received by the other remote terminal stations. For a given television channel, all terminal stations use the same audio return channel, thereby communicating in a party line mode. In one embodiment, the return audio carriers for the private television channels are generated at each terminal station and the audio interaction is provided by a novel audio insertion unit using a phase locked loop which does not require demodulation and remodulation of the video signal. In another embodiment of the invention, the audio carriers for the return audio channels are generated at the central station and transmitted to the terminals for modulation by the respective return audio inputs.
Abstract:
A venturi-head for a vacuum system utilized as a source of negative pressure for vacuum cups and the like which has incorporated therein a safety shut off valve to hold vacuum in the vent of a failure of actuating jet stream and requiring a pressure release available only when pressure source is furnishing required pressure.
Abstract:
In a fingerprint identification system utilizing real time fingerprint input of a person, a means for limiting the pressure with which a fingerprint is applied to prevent illegible or smudged prints which are not faithful reproductions of the intended input.
Abstract:
A method of forming a solid structure to carry loads and have an attractive appearance which has a smooth and attractive outer surface formed as a fiber-included resin lay-up of a hard material having an inner surface with hooked projections provided by pulling material from the lay-up and allowing such to droop by gravity and thereafter depositing hardenable aggregate thereover to form an interlocking bond.
Abstract:
A circuit for the rapid turnoff of the load current in an electrochemical machining apparatus is disclosed. The approach employed is to shunt the load current through an SCR after a short circuit has been detected. The circuit operates to induce an additional voltage in the load circuit to reduce the load current to zero for a sufficient length of time to permit the SCR''s in series with the load to recover their blocking capability.
Abstract:
A zone plate scanner for wide bandwidth laser recorders utilizing a rotating disc having pairs of peripheral windows, each containing a zone plate, one set of windows in each pair being spaced circumferentially at a constant radius, and a second set being similarly spaced circumferentially but each having a different radius. The spacing changes the grating frequency for each pair and encodes each track on a moving film in a manner which eliminates interference in close spacing and reduces the criticality of readout equipment.
Abstract:
Calculator for determining proper exposure times in making color prints from color negative films comprises an opaque mask with three series of windows having respectively blue, green and red filters of graduated density. The windows have double wedge shape to provide contiguous points and other points remote therefrom. Color print paper is test exposed to light passing through the negative, a diffusion filter, and the graduated filters; when the paper is developed, the correct exposure time is indicated on the paper by the faintest double wedge image which has sharply defined points. A filter device for use in conjunction with the calculator comprises a wheel rotatably mounted on the lens barrel of a projector and having a series of openings: one clear for focusing, one with a diffusion filter for the test exposure, and the others with blue, green, and red filters respectively.
Abstract:
A radar processing system and method for extracting from received radar data information about moving targets even though the absolute energy reflected by these targets is much less than the energy reflected by the stationary background. The processing system includes an optical recorder for recording the magnitude of the reflected energy and a coherent optical processor for processing the recorded information by computing the power spectrum of the Doppler frequency shift in the recorded information and thereby distinguishing a true target from the stationary background. In addition, means are provided for eliminating from the recorded information any range ambiguities produced at higher pulse repetition frequencies because, at these higher frequencies, echoes from far ranges return at the same time as echoes generated by later radar pulses return from near ranges. The optical processor can operate on data from airborne or groundbased radars.