Abstract: The security system for homes and small offices provides snapshots of potential trespassers for viewing on conventional television receivers. The system consists of at least one scene capture unit, a scene recovery unit, and communication links between the scene capture units and the scene recovery unit. A scene capture unit consists of a motion detector, a conventional television camera, and circuitry which converts the camera signal into a sequence of integers that is stored in semiconductor memory and then communicated to the scene recovery unit. The scene recovery unit generates from the sequence of integers communicated by the scene capture unit a signal which, when fed into a conventional television receiver, causes the scene recorded by the camera to be displayed on one portion of the television screen and the time of occurrence to be displayed on another portion.

Abstract: A video display terminal for selectively displaying a format of 80 characters per line and a format of 132 characters per line includes a microprocessor driven controller, a VCO for supplying the dot clock frequency, a frequency divider connected between the VCO and the controller and a crystal controlled phase detector coupled between the horizontal deflection signal output of the controller and the input of the VCO for smoothly changing the dot clock frequency in response to software induced changes in the controller.

Abstract: In a data processing system, an input line voltage is provided to a series voltage regulator which, in turn, provides well defined DC voltages to various logic devices including a system controller, such as a microprocessor. System controller operation is degraded by variations in the DC voltage provided thereto, generally resulting in the erroneous writing of data into a nonvolatile memory in the data processing system when the DC voltage provided to the system controller drops below a given voltage level caused by, for example, variations in the input line voltage. The input line voltage to the data processing system is monitored across the series voltage regulator for deselecting/write disabling the memory in the event the input voltage drops below a predetermined level, such as due to power transients, to prevent loss of data stored in the memory.

Abstract: In a microprocessor-controlled video display terminal, coded data is used to represent characters and attributes associated therewith. Each attribute byte has associated therewith a designated control function such as underlining, inverse video, blanking, dimming, etc. If each attribute byte is comprised of M bits and there are N different attributes available for display, where M>N, then some of the bits comprising the attribute byte are not used. These unused bits are used in the present invention to represent a protected field in a character random access memory (RAM) for a given location, or address, on the video display and are read from an attribute RAM by the microprocessor for restricting access to the character RAM. In this manner, the writing of new data into selected portions of the video display is precluded.

Abstract: A system eliminates digital switching video noise by performing several microprocessor controlled operations in a television receiver during the vertical retrace interval. A microprocessor maintained in an idle state until detection of a vertical retrace pulse initiates channel selector keyboard scan, channel number display update, and phase locked loop tuning information update during the vertical interval by multiplexing control outputs therefrom on a limited number of microprocessor IC pins. This approach provides for the regular and continuous updating of television receiver operating parameters while eliminating digital switching noise from the receiver's video display generated by the transfer of digital data representing the aforementioned operating parameters.

Abstract: A video monitor having a common input terminal is selectively operable, automatically, from RF input signals or baseband video input signals. A high pass filter is provided at the input of an RF channel which includes RF amplifying means, detecting means and a video output. A low frequency coupling capacitor is provided at the input of a baseband video channel which also includes a video output. A video amplifier having a sync tip clamping circuit is AC coupled to both said channels. A peak detector and a transistor switch are coupled to the common input terminal for disabling the RF channel responsive to the input of a baseband video signal to minimize noise.

Abstract: Initialization problems in a microprocessor controlled system due to power interrupts or rapid cycling of the ON/OFF control are eliminated by insuring that a logic initialization signal is provided only after microprocessor power up and is removed before the microprocessor is subject to a power outage. By insuring the proper sequencing of the microprocessor initialization input signal and the supply voltage applied thereto, microprocessor operation is initiated under the proper logic and timing conditions. The present invention is particularly adapted for use in a microprocessor controlled tuning system for a television receiver where the power supply is operated not from horizontal scan circuitry but from a conventional 60 Hz power supply. The large time constants used with this low frequency power supply for optimum signal processing generally result in a more rapid decay of the power supply input than the power on reset, or initialization, signal.

Abstract: A tuning system is described for use with a television receiver which has channel selection keys on a keyboard for selecting a desired television channel. The system employs a frequency synthesizer for tuning the receiver's local oscillator to a selected television channel. For fine tuning, the system employs a fine tuning key which doubles as a channel selection key. Actuation of this key places the system in a fine tuning mode, and a logic circuit responds to actuation of a channel-up or channel-down key for causing the receiver to be fine tuned in the selected direction. In the preferred embodiment, fine tuning and channel selection are controlled by the logic circuit so as to occur during the receiver's vertical interval to eliminate digital switching noise from the receiver's image.

Abstract: Apparatus for automatically restoring information concerning a plurality of broadcast station frequencies in a microprocessor type tuning system when such information is inadvertently lost from a volatile memory.

Abstract: Apparatus is provided for automatically compensating for frequency drift in a digitally tuned varactor tuner. An Automatic Frequency Control signal for tuning the varactor tuner is produced in response to the direction of a tuning error. A signal level detector is used to inhibit the AFC signal when weak signals are being tuned by the varactor tuner thereby preventing continuous searching by the tuning system.

Abstract: A channel number display device for a television receiver for displaying the numerals of the channel to which the receiver is tuned with the display being initially bright immediately after a channel change, and then after a predetermined time of several seconds, being reduced in brightness so as not to distract from the program material. Through the use of a thyristor, regardless of the number of individual elements in the numerical display, the brightness levels may be held to predetermined quantities.BACKGROUND OF THE INVENTIONOver the years, it has been a desire of television manufacturers to provide a display of the channel numbers on the television receiver so that they can be easily read, especially immediately after tuning to a new station so that the viewer can determine if he is at the desired station. This is especially true for television receivers having remote control, wherein the viewer is spaced at the viewing distance from the receiver while tuning to a new station.