A capacitance length and/or angle measuring device has a transducer comprising a stationary part (1) forming a scale and a part (2) displaceable parallel over the surface of the scale, at a short distance therefrom and acting as a sensing unit. The opposite surfaces of the scale and sensing unit are provided with capacitor coatings (5,6,7,8,9). The mechanical quantity to be measured causes an area vibration of a capacitor, the capacitance variation resulting therefrom acting as a variable capaci...

A frequency-hopping radio communication system is disclosed comprising a control unit which transmits to and receives from each of a plurality of slave stations using a frequency-hopping mode of operation. During a start-up mode, the control unit communicates a starting message to each slave station using a predefined frequency. The message identifies to each slave station a frequency-hopping sequence to be used to select the frequencies from a group of frequencies for transmission to and recept...

A monitor interface circuit for adapting a color display monitor to a selected one of various types of computers which generate different types of color display data receives the display data and one of several horizontal scanning frequency signals from the computer and mixes the display data as a function of the one horizontal scanning frequency to thereby generate a proper display signal for the monitor.

The present invention provides for the combining of image and graphics data in a high-performance raster graphics workstation. It allows the definition of windows on the screen, the dynamic control of the position of those windows, the magnification factor (integer zoom), and a color translation table, corresponding to each window. All these functions are under user control. Response time of 10 new frame buffers generated per second provides a "real" time response.

A computer graphic interface allows a user to obtain descriptive information concerning a feature of a displayed image by pointing to the location of the feature. Conversely, the user may enter descriptive textual information, and the locations of responsive features are indicated. The data processing and memory storage requirements are minimized by encoding information about the image as a pixel bit map, and a color map in which the addresses or indices of the color map are correlated with the ...

In an image display apparatus, a frame memory for storing original data and a display memory for storing display data are used as memories for storing image data. The image data is read out from the display memory and is displayed by a display system. When image data transfer from the frame memory to the display memory is performed through a programmable data conversion memory, data conversion is performed as image processing. The image display apparatus has a masking memory having an image area...

A two-wire transmitter having a detecting section for detecting a physical variable to be measured to produce a detection output, first and second constant voltage devices connected in series with a two-wire transmission path, a signal processor driven by a voltage supplied by the first constant voltage device for converting the detection output into representative serial pulse signals and a switching circuit which is connected in parallel with the second constant voltage device and is turned on...

A technique is described for animating graphics objects (sprites) on a display. The display manager allows a user to select a sprite from the display or from a sprite table. Then the user selects the operation to perform on the sprite. Enabled operations include hiding the sprite, showing the sprite, redefining the sprite, placing the sprite or moving the sprite. The move operation allows the user to make the sprite the current cursor character and move it around the display under the control of...

A digital video generator provides for smooth scrolling of a video image across a video display device. A digital memory contains data to be displayed. Under control of a computer this data is transferred to a display memory as needed. The data is displayed with a gray scale intensity level for each pixel. Two successive pixels in the direction of movement are read out of the display memory, a current pixel and a next pixel, and are added together in a mixer with a weighting factor determined by...

In a vehicle presence detection system in which an inductive sensor loop is the frequency-determining element of the tuned circuit of a loop oscillator, discrimination against variations in inductance due to environmental changes is achieved by comparing detect and tracking reference numbers with a sample number that is a function of the oscillator frequency and updating each reference number repeatedly at real time intervals independent of loop oscillator frequency. The current sample number is...