Abstract: A method for testing a signal path for mark ratio tolerance includes generating a varying test pattern by selecting between a first pattern and a second pattern according to a defined sequence; and sending the varying test pattern over the signal path. An apparatus disposed in a communication system includes a selection circuit for generating a varying test pattern to send over the signal path, the selection circuit generating the varying test pattern by selecting between a first pattern and a second pattern according to a select sequence signal, and a sequencer coupled to the selection circuit, the sequencer providing the select sequence signal to the selection circuit, the sequencer generating the select sequence signal according to a mode value. The mark ratio tolerance of a system can be tested, varying the data density of one portion of the signal path while maintaining a constant data density on another portion of the signal path.

Abstract: An isotropic, direction and point parameterization (DPP) light-field model is used for rendering graphics images in a hologram production system. Using the DPP light-field models can reduce image artifacts, reduce oversampling, decrease rendering time, and decrease data storage requirements.

Abstract: In a telephone system having multiple working metallic interface units, a method and a structure provide protection by assigning to each metallic interface unit a partner unit, which is another metallic interface unit. Under this arrangement, when a failure occurs in a working metallic interface unit, its partner unit switches the ring/tip input signals of the failed metallic interface unit to a protection bus. A standby or protective unit then takes over by receiving the rerouted tip/ring signals from the protection bus. The failed working unit can then be removed from the shelf without disrupting service.