Abstract: An on-chip test bus circuit for testing a plurality of circuits and an associated method. The test bus circuit consists of a test bus and a plurality of switching circuits which selectably provide electrical connections between the respective circuits and the test bus. The plurality of switching circuits are configured to transfer an electrical charge between a node disposed within each switching circuit not selected to provide an electrical connection and a respective charge source or sink. The charge source or sink may consist of a low-impedance, substantially noise-free DC voltage or signal source.

Abstract: A system and method for distribution of cryptographic keys to data encryption and decryption devices used to protect digital video/multimedia data transmitted over a display link between a digital video/multimedia source and a display device are provided. The digital data from a digital video/multimedia source, such as, for example, a Digital Versatile Disk (DVD) player, is encrypted prior to transmission on the display link. The encrypted digital video/multimedia data is received from the display link transmitter, decrypted and sent to a display device. Secure digital data input lines are used to load cryptographic keys into RAM on the same integrated circuit as the encryption device. A public key system is used to cipher the video decryption keys, so that the decryption keys can be sent to the display link receiver. Use of key management and storage that are external to the data encryption or decryption devices enables downloading of new keys from external key sources.

Abstract: An on-chip test bus circuit for testing a plurality of circuits and an associated method. The test bus circuit consists of a test bus and a plurality of switching circuits which selectably provide electrical connections between the respective circuits and the test bus. The plurality of switching circuits are configured to transfer an electrical charge between a node disposed within each switching circuit not selected to provide an electrical connection and a respective charge source or sink. The charge source or sink may consist of a low-impedance, substantially noise-free DC voltage or signal source.

Abstract: A system and method of creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible.