Logitech, Inc.

Gazelle Graphic Systems Inc.

Dorrough Electronics

H Maurice France

Kenneth S Gold

Anthony Edward Zank

Michael N Gilano

Michael L Dorrough

Electromagnetic position transducer having active transmitting stylus

For monitoring, metering and dynamically displaying key static and dynamic parameters of composite video signals and visually indicating compliance status relative to important system specifications, this electronic meter is particularly useful in connection with video cameras. In studio environments, the compliance indications supplement existing capabilities, and in remote locations where large, complex and costly CRT type waveform monitors are not feasible, the compactness of this video meter provides an unusual degree of picture quality assurance. A bar/graph type LED display provides two independent scale regions: a sync region dynamically displaying sync amplitude, and a picture region dynamically displaying average picture levels in a bar mode and peak levels in a dot mode. The response times of the sync, average and peak level are selectable. Peak indications are lengthened to a display time which is optimal for human response to short term events. A monochrome video meter embodiment displays average luminance levels in a bar mode and peak luminance levels in a dot mode. Presence/absence of sync is indicated by a bi-color LED. Additional parameter status may be indicated by a panel-mounted bi-color LED which provides four indication modes. For color video, a chrominance embodiment, used along with the monochrome embodiment and similarly packaged, displays color burst amplitude and average chrominance in a bar mode, peak chrominance in a dot mode, and optionally monitors color burst phase relative to horizontal sync.

Dynamic video luminance and chrominance meter

Disclosed is electromagnetic transducer that does not require complex analog to digital, digital to analog converters, microprocessors or large memory circuitry. The transducer has a helical tablet coil with tap nodes spaced between its end extremities. In one configuration, an oscillator drives the tablet coil for simultaneously producing oppositely directed currents on opposite sides of selected taps, creating a moving fringing field that is compatible with modern graphic display tablet technology. A control circuit of the transducer has a closed-loop integrator for detecting the centroid of a received stylus signal from a stylus coil. Analog and digital versions of the integrator are disclosed. In another configuration, the oscillator drives the stylus coil for variably coupling magnetic flux to the tablet coil, a receiver signal that is coupled from the end extremities being responsive to the position of the stylus coil and the taps selected. A preferred configuration of the tablet coil has separate oppositely wound coil components.

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Palos Verdes Estates, CA, United States of America

H Maurice France