Abstract: A bit density controller is capable of transmitting no more than 15 consecutive 0-bits to be sent serially in a data bit sequence, without a 1-bit, for operating on the AT&T T1 network. The bit density controller includes a state machine having a state index and a substitution device coupled to the state machine. The bit density controller additionally can include a buffer for storing at least one frame of the data bit sequence, a memory for storing overhead bits, and an overhead bit inserter for inserting overhead bits into the data bit sequence.

Abstract: A flat mail collator is provided having a flat base with a rectangular shape and a handle connected to the flat support. A plurality of leaves having a rectangular shape are connected to the flat base for defining spaces between the adjacent ones of the leaves. The plurality of leaves are coded for a plurality of addresses for sorting mail by address by inserting individual pieces of mail between these. Upon completion of the sorting operation, the mail is removed from the leaves by the lifting the flat base by the handles and tilting the flat base and allowing the sorted mail to slip from between the leaves and remain sorted.

Abstract: A class SM amplifier is provided having a threshold circuit with a plurality of threshold levels for generating a plurality of threshold signals. In response to an input signal passing a particular threshold level, the threshold circuit generates as an output a particular threshold signal. A voltage supply is provided having a plurality of voltage levels. The class SM amplifier includes a plurality of transistors coupled to a load and the threshold circuit, and the plurality of voltage levels from the voltage supply. The transistors switch a particular voltage level across the load in response to a particular threshold signal from the threshold circuit. The plurality of voltage levels are adjusted to approximate the input signal.

Abstract: A class SM amplifier is provided having a threshold circuit with a plurality of threshold levels for generating a plurality of threshold signals. In response to an input signal passing a particular threshold level, the threshold circuit generates as an output a particular threshold signal. A voltage supply is provided having a plurality of voltage levels. The class SM amplifier includes a plurality of transistors coupled to a power combiner and the threshold circuit, and the plurality of voltage levels from the voltage supply. The transistors switch voltage levels across the power combiner in response to a particular threshold signal from the threshold circuit. The power combiner is coupled to a load, and outputs the combination of the voltages from the transistors across the load. The plurality of voltage levels are adjusted to approximate the input signal.

Abstract: A passive system for detecting the position and trajectory of a moving body, moving in the air, on the ocean or below the ocean. This apparatus operates by detecting perturbations in the earth's magnetic field responsive to the movement of a body through the field. At least two spaced magnetometers are provided to detect the perturbations of the earth's magnetic field, whereas, the system works more efficiently with an array of sensors. These two sensors are used to filter out the ambient noise. The outputs of these sensors are digitized and inverted through correlation procedures and an output is provided on a display.

Abstract: A circuit for automatically operating a switching power supply is capable of operating from first and second input voltage ranges. The circuit changes the switching power supply from a full-wave rectifier circuit to a voltage doubler rectifier circuit by electrically connecting first and second nodes. The circuit includes a rectifier circuit and a voltage level sensing device for generating an output voltage to trigger a triac, which connects the first and second nodes.

Abstract: In a method of and apparatus for limiting program execution to only an authorized data processing system, a proprietary program, together with first and second authorization codes, is stored on a magnetic disc or other storage medium. The first and second authorization codes are read. A hardware module containing a pseudorandom number generator unique to the authorized system receives the first authorization code as a key. The resultant number generated by the number generator, which is a function of the key and particular pseudorandom generator algorithm, is compared with the second authorization code in direct or encrypted form. An execution enable signal is generated in response to a positive comparison to enable the stored program to be executed.