Abstract: A prescramble encoding mechanism divides a data word into a plurality of sequences of data bits for transmission over a fiber optic communication link. Complementary versions of control bits and odd and even parity bits are interleaved between the bit parallel data and control signals, divides a parallel data word possible series of consecutive bits of the same logical state is less than a predetermined number related to the length of the data bit sequences and to placement of the complementary control bits and even and odd parity bits. The data frame is then scrambled prior to transmission over the fiber optic link. Depending on the exact nature of the scrambling and descrambling process, a single-bit link error may produce a plurality of bit errors in the descrambled frame.

Abstract: An audio amplifier for providing a power boost for telephone-sourced audio signals that drive one or more paging speakers employs a class D amplifier and a state variable feedback network, which monitors voltage and current levels of an audio output filter to which the paging speakers are coupled, so as to adjust the operation of the amplifier circuit, as necessary, to compensate variations in the speaker loading of the audio output filter. The class D amplifier includes a pulse width modulator, which controls the switching of a power H-bridge-configured switching circuit. The switching circuit sources and sinks current with respect to the paging speaker load. The output of the power bridge switching circuit is a high energy square wave-type signal, which is filtered in a downstream audio filter to remove the switching transients and preserve the desired voice paging signal for application to the paging speakers.

Abstract: Exposure or lack of adequate protection for the terminal portion of a battery against the environment is remedied by a protective `boot`, which is formed of a waterproof pliable material and is configured to fit snugly over the casing of the battery and seal the terminal portion of the battery against the surrounding environment. The battery `boot` may be molded from a rubber material or plasticized polyvinylchloride in the form of a cap portion and a sidewall portion integral with the cap portion. The sidewall portion is shaped to conform with an outer surface portion of the battery casing and is dimensioned such that, when the cover is pliably stretched so as to fit over the battery, the cap portion covers the terminals of the battery, while the sidewall portion fits tight against the battery casing and seals the outer surface portion of the battery against the entry of moisture, foreign matter and the like.

Abstract: An amplifier circuit employs a differential amplifier having first and second differential inputs and having an output for providing an output signal which varies according to a difference between magnitudes of input signals provided at the first and second inputs, a high impedance front end which is coupled to the first input of said differential amplifier and which accepts an input voltage, and a feedback circuit which is interposed between the second input and the output of the differential amplifier so that error characteristics of the feedback circuit are substantially similar to error characteristics of the front end and signal errors introduced by the high impedance front end are canceled by signal errors provided by the feedback circuit. The differential amplifier can be an operational amplifier and the high impedance front ends and the feedback circuits can be source follower FET circuits each having an FET transistor and a resistor connected to the source terminal of said FET transistor.

Abstract: An adaptive digital filter uses a weight adjustment unit for adjusting the weights of an adaptive digital filter according to one or more input signals to the digital filter and according to an error signal indicative of the difference between the actual and desired outputs of the digital filter. The weight adjustment unit has a first low-pass filter for low-pass filtering a signal indicative of the product of the error signal and the one or more input signals, a squarer for squaring the output of the first low-pass filter, a second low-pass filter for low-pass filtering the output of the squarer to extract the D.C. component thereof, a third low-pass filter for low-pass filtering a signal indicative of the output of the error signal squared to extract the D.C.

Abstract: A convertible sulky is interchangeable between stand-up and sit-down configurations so as to allow a mower operator to operate the mower from either a standing or seated position behind the mower. The convertible sulky comprises an H-shaped support wheelbase frame, to opposite legs of which a pair of wheel-mounting columns are affixed. Attached to the H-shaped support wheelbase frame member is a T-shaped mower attachment frame, having a central leg, an upper end of which is inclined forwardly H-shaped support wheelbase frame for attachment with the rear of the mower, by means of a ball-hitch fixture. A pair of generally L-shaped foot plates are secured to the frame structure formed by the T-shaped mower attachment frame and the H-shaped support wheelbase frame.

Abstract: A method of defining the operation of switching system peripherals is comprised of storing a software program for operating the peripherals in a switching system; storing at least one table of data for access by the program for defining operating parameters of a corresponding at least one peripheral; modelling a prototype of the peripheral in a remote host system by creating a human-machine-interface simulating the peripheral; storing a control table of data corresponding to the modelled prototype in a memory for the host system; and downloading the control table into the one table, whereby operation of the peripheral is controlled by the operating software programs and the data in the at least one table.

Abstract: An interconnect laminate structure integrates RF and auxiliary (e.g. digital and D.C.) signalling capabilities in a common structure by means of a stacked conductor-plated dielectric configuration that facilitates access to and routing by channelline/waffleline RF transmission links and separate control (e.g. digital, power supply) links, without having to perform laborious manual routing tasks to effect auxiliary connectivity among the components of a network. The interconnect structure includes a first dielectric layer having a channel formed in a first surface thereof, the channel having a conductive surface and configured to accommodate the insertion of a dielectric coated conductor into the channel so as to form an RF transmission line. Second dielectric layers, each of which has a conductive layer formed on a first surface thereof, are mounted together with the first dielectric layer in a laminate assembly.

Abstract: A method of translating a command into natural language is comprised of the steps of: storing compressed words of the language once as either a word or subset of a word or group of adjoining words in a memory; storing a numeric indicator of each group of tokens which form a natural language string, with position locators; looking up the position locators in response to the command; accessing the memory to retrieve the compressed words; and providing a string of the tokens as a natural language string.

Abstract: A transient voltage surge suppressor comprises a first series circuit formed of a normally-off voltage surge-responsive gas discharge tube and a first voltage clamping device connected across input terminals to which a line voltage is applied. It also includes a second series circuit formed of a first electrical energy absorbing impedance element and a second voltage clamping device connected across the first voltage clamping element, thereby forming a voltage-clamping, voltage divider circuit which clamps the voltage across the first voltage clamping element at a voltage level reduced in comparison with that obtained by the first series circuit alone. When the gas discharge tube turns on, it places both voltage clamping devices in the circuit simultaneously, so that the let-through voltage appearing across output terminals can be reduced to the voltage clamped by the voltage-clamping, voltage divider circuit.

Abstract: A reset mechanism for a random access memory array comprises an auxiliary reset circuit, which does not require modification of the contents of the memory itself. For a random access memory capable of storing M, N-bit words, the auxiliary mechanism includes a plurality of M reset state circuits that are respectively associated with the M words of memory. The reset state circuit preferably comprises an additional `resetable` memory cell for each word of memory, which is integrated within the structure of the memory itself. In order to reset one or more words of memory, the associated reset state circuits are placed in a reset state-representative condition. The state of each reset state circuit is used to controllably mask (e.g. is logically ANDed with) the contents of its associated word of memory, whenever that word is read out. If the reset memory cell has been cleared, then regardless of the contents of its associated word in memory, the mask will cause the addressed memory word to be output as all zeros.

Abstract: A laser driver mechanism for image reproduction maintains linear operation over a wide frequency an dynamic range of amplitude-modulated input signals by means of a first feedback loop and a second feedback loop. The second feedback loop contains a first amplifier coupled to receive the input signals and an output coupled to a second amplifier that drives an injection laser diode. A photodetector is coupled downstream of and external to a sealed unit in which the injection laser diode emitter, an associated photodetector of the first feedback loop and beam extraction optics are housed. The photodetector of the second loop has an output coupled to the second amplifier, so that the second feedback loop serves to compensate for non-linearities in the laser driver including those of the first feedback loop.

Abstract: A hydraulic height adjusting device includes a sealed upright cylinder body in which a piston is provided. A piston rod is connected to the piston at one end and extends through a lower end of the cylinder body. A first positioning member is fitted in the cylinder body adjacent to an upper end of the latter. A second positioning member has an axial hole formed therein and is fitted in the cylinder body between the first positioning member and the piston. A hollow tube has a radial hole formed through a wall portion thereof and extends axially in the cylinder body between the first and second positioning members.

Abstract: Identification and extraction of hybrid, frequency-hopped direct sequence pseudo noise (FH/DS), signals from a multiband signal environment is effected by a sequential signal processing technique which examines the distribution of the energy content within a prescribed sub-spectrum window that is iteratively scanned or `slides` across the overall signal spectrum of interest. Based upon this energy content distribution, in particular the extent to which a sub-spectrum window contains energy that exhibits significant conjugate phase symmetry associated with a direct spread signal, the inventive signal processing technique proceeds to emphasize the spectral composition of components of which hybrid signals are comprised and to deemphasize the spectral composition of signals other than those contained in hybrid signals. Potential hybrid signal candidates whose spectral composition has been emphasized are then selectively combined with the deemphasized signals to isolate and identify the hybrid signals.

Abstract: Wafer surface degradation in a photoexcitation dry cleaning process, due to volatilization of surface halides that allows the exposed silicon surface to be further etched, is obviated by controlling the conditions of the process, specifically silicon wafer surface temperature, such that silicon reaction products that are formed on the surface of the wafer in the presence of the photoexcited disassociated halogen radicals do not volatilize. The silicon wafer is placed upon a low temperature chuck. When the halogen gas within the reaction chamber is irradiated with ultraviolet light, it produces disassociated halogen atoms that react with the surface of said silicon. Irradiation of the halogen gas and the surface of the silicon wafer is controlled by an optical shutter, in order to limit the amount of ultraviolet radiation that strikes and is absorbed by the wafer.

Abstract: Depletion layer depth and semiconductor real estate occupation area shortcomings of conventional MOS capacitor architectures that are formed on lightly doped semiconductor material are obviated by augmenting the MOS capacitor structure with a pair of opposite conductivity type, high impurity concentration regions, both of which are directly contiguous with the lightly doped lower plate layer that underlies the capacitor's dielectric layer, and connecting both of these auxiliary heavily doped regions to a common capacitor electrode terminal for the lower plate of the capacitor. If a high negative charge is applied to the upper plate overlying the thin dielectric layer, holes are readily supplied by the auxiliary P+ region. Conversely, if a high positive charge be applied to the upper plate, electrons are readily supplied by the auxiliary N+ region. By connecting both the auxiliary N+ and P+ regions together, a deep depletion condition is prevented for either polarity of the applied voltage.

Abstract: A decimating memory includes a memory having addressable memory locations. The memory forms a plurality of registers, each of the registers including at least one addressable memory location. The plurality of registers form a forward shifting data section and a reverse shifting data section. A first decoder operates the registers in the forward shifting data section and all but a first of the registers in the reverse shifting data section as FIFO registers via read and write addressing of the addressable memory locations to input and output data samples. The read and write addressing of the addressable memory locations is offset with respect to one another to provide a decimation factor. A paintbrush decoder operates the first register in the reverse shifting data section as a LIFO register for reverse sequencing data samples within blocks of data samples received from the forward shifting data section. Each of the registers in the forward shifting and reverse shifting data sections provide an output.

Abstract: Dual polarity source/drain extensions are formed simultaneously in both PMOS and NMOS devices of a CMOS architecture using a common set of implants, so to be contiguous with one or both of source and drain regions of both the PMOS and the NMOS structures. The complementary conductivity lateral extension region configuration may be either an N over P or a P over N structure. The dual implant methodology can be carried out with no explicit masking steps, yielding MOS device which have source/drain extension regions that are self aligned to the gate and have minimal overlap capacitance.

Abstract: The occupation area and thickness of dielectrically isolated island-resident transistor structures, which employ a buried subcollector for providing low collector resistance at the bottom of the island, are reduced by tailoring the impurity concentration of a reduced thickness island region to provide a low resistance current path from an island location directly beneath the base region to the collector contact. The support substrate is biased at a voltage which is less than the collector voltage, so that the portion of the collector (island) directly beneath the emitter projection onto the base is depleted of carriers prior to the electric field at that location reaching BCVEO, so as not to effectively reduce BVCEO.

Abstract: A digital tandem channel unit installable in an intermediate central office of a digital carrier telephone network maintains the digital format of the T1 traffic in the course of a DS0 tandem cross-connect, so as to eliminates the possibility of corruption of voice/data traffic, as may occur in a conventional `analog` office cross-connect tandem pair due to quantization errors introduced into the data stream in the course of the digital to analog conversion of the data. Also, the invention incorporates control software in each tandem channel unit's micro-controller that allows it to respond to analog tone signalling test procedures initiated from either two or four-wire channel ports of network access equipment.