Abstract: A high performance latch for read and write operations in RAM having a Complimentary Interlock circuit that eliminates the need for external timing to the RAM which might limit its high performance operation. For both read and write operations, the complementary interlock circuit extends a latching signal until valid data appears on the read or write data lines, thus preventing a valid data miss.

Abstract: A multimedia dynamic random-access memory (DRAM) or video random-access memory (VRAM) having enhanced block overwrite capabilities includes a plurality of sense amplifiers which are selectively coupled to an array of memory cells via paired bit lines for sensing/writing charge to the memory cells. Each sense amplifier is controlled by a primary set device and a secondary set device. The secondary set device is of smaller size than the primary set device but still sized sufficiently to maintain accessed data appearing on the paired bit lines. Upon decoding of a block overwrite request, the primary set device is momentarily turned off to facilitate forcible overwriting of selected sense amplifiers with new data while the secondary set device maintains data appearing on unselected sense amplifiers. Once block overwrite is complete, the primary set device is reactivated and charge is restored to the memory cells.

Abstract: A signal margin testing system is provided for a memory having a word line voltage boosting circuit which uses a test mode decode circuit to selectively disable the word line boosting circuit and then read out data from storage cells in the memory.

Abstract: A signalling device for use in combination with a door so as to signal when the door is attempted to be opened as by inward pivotal motion with respect to the frame in which such door is supported. Normally the alarm is an audible one such as a horn or siren, and in this manner, attempts to open the door are brought to the attention of those inside the structure. The device functions as a dead bolt lock and the signal aspect of the device may be overridden by a key-operated deactivation assembly. Generally the device operates by means of a transversely slidable bolt which may have electrical contact on the inner surface thereof for engagement with a contact on the inside of the door or housing attached thereto. Other contact locations are also contemplated. The bolt may be spring biased away from the door or housing contact and an appropriate electrical circuit is closed and the signal activated upon door movement as by attempted entry.

Abstract: A highly efficient system for propelling high speed water borne craft is closed. The use of an inclined shaft which permits an efficient machinery arrangement is facilitated by driving the vessel by a unique propeller which is designed to operate while partially submerged. The propeller is raked to maximize the horizontal thrust component produced as the propeller blades sweep through the water. The partially submerged propeller provides an attractive method for reducing appendage drag which is associated with traditional horizontal or inclined propeller shaft systems. Further, this concept and design represents a propeller system which unique among propeller systems produces near zero transverse forces.