Abstract: An amplitude/phase discriminator network the entirety of which is integrated on the same (GaAs) semiconductor chip, obtains a quadrature phase split through the use of a pair of orthogonal phase generators each of which comprises an all-pass network coupled with a pair of differential amplifiers. An unknown signal of interest, the phase and amplitude of which are to be derived, is applied to one pair of all-pass networks, while a reference signal, the amplitude and phase of which are known, is applied to the other pair of all-pass networks. Four quadrature outputs produced by the differential amplifiers contained within the pair of orthogonal phase generators are selectively coupled to a signal combining stage comprised of a diode detector-low pass filter network.

Abstract: The surface area utilization efficiency of an array of antenna elements distributed over a prescribed geometrical surface is increased by configuring that surface as an ellipse of revolution. Preferably, the ellipsoid surface over which the antenna elements are distributed has a shape such that the major axis of the ellipse in rotation is twice the length of the minor axis. This results in an optimal, near constant illuminated surface area for any angle in the hemisphere. Because a more efficient use of the antenna surface area is provided, the number of antenna elements that is required to obtain the same array gain in all directions in the hemisphere can be reduced substantially when compared with spherical or tetrahedral configurations of conventional hemispherical coverage arrays.

Abstract: Prior to normalizing floating point number, a maximum negative number detector is employed. In order to determine whether a number is a maximum negative number, the inventive scheme examines the left-most (most significant) bit of the bit sequence to be scaled is examined. For positive numbers (where the bit is a zero) the normalize count is carried out without modification. Upon encountering a negative number the bits of the number are examined. The maximum negative number detector contains logic circuitry that counts the displacement from the left-most bit position to the location of the first zero bit from that position. It also counts the displacement from the right-most bit position to the location of the first one bit from that position. For a maximum negative number (one or more ones followed ony by one or more zeros) these two counts will differ by a single bit. This value is then used to prescale the normalization counter so that normalization may proceed.

Abstract: A method for controllably varying the selectivity of reactive etching process for etching a polysilicon film, involves the addition of an adjustable amount of oxygen (O.sub.2) to a chlorine based chemistry (e.g. Cl.sub.2, HCl) during the etching process. The adjustable amount of oxygen permits the selectivity to be varied from a low to moderate rate at the beginning of the etch and through most of the film thickness to as high a selectivity as is required for overetch, to allow anisotropic removal of polysilicon without penetrating thin oxide. Selectivity is effectively proportional to the oxygen concentration and may be varied from a low to moderate selectivity value (e.g. 20:1) to a high selective value (e.g. 100:1) of polysilicon oxide etch rate in a controlled manner.

Abstract: A process for forming an electric field shielding layer in a SIMOX substrate entails carrying out a high beam-current oxygen implant over a manufacturing-acceptable period of time, which increases the wafer temperature (on the order of 500.degree. C.) causing in situ annealing of the substrate and suppresses the initial formation of an EFS layer. After the oxygen implant step and prior to subsequent annealing, however, the oxygen implanted silicon substrate is subjected to a medium dose silicon implantation (10.sup.15 -10.sup.16 Si.sup.+ cm.sup.-2) with projected ion range near the interface of the silicon-on-insulator film and the buried oxide layer. This high-throughput implantation can be carried out at or near room temperature in only several minutes and effectively creates an oxygen-doped amorphous silicon precursor EFS layer atop the buried dielectric layer, while leaving the overlying surface silicon layer relatively undamaged.

Abstract: The ability of alkali hydroxide to etch silicon is enhanced by the controlled addition of metallic salts which readily dissociate in a strong base (pH.gtoreq.10) solution. When introduced into the alkali hydroxide (e.g. potassium hydroxide) solution, the controlled concentrations of additive metallic ions increase the electronegativity of the solution and thereby enhance its ability to attract electrons away from the silicon atoms within the crystal lattice being etched. By adding controlled levels of properly chosen electropositive ions, the rate at which the electrons are removed from the silicon atoms in the surface planes of the crystal lattice that are exposed to the etching solution can be controllably increased. As a result of removal of the electrons from the silicon atoms, the silicon atoms dissolve out of the crystal planes at rates modified by the degree of impurity addition, resulting in improved etching charcteristics and geometries over that of conventionally employed alkali hydroxide solution.

Abstract: A telephone line test and display circuit for enabling a craftsperson to automatically monitor a plurality of communication aspects of a telephone line without impacting any communications that may be taking place over the telephone line being monitored includes a communication capability detection and indicator unit through which the craftsperson may observe the DC operational state (busy/idle, battery polarity, talk battery present) condition of the line by observing a pair of light emitting diodes. The light emitting diodes are color-coded in accordance with operational status conditions being monitored and are illuminated in either a steady state or flashing condition, depending upon the DC state of the line. Also contained with the test and display circuit is a frequency discriminator/display unit, having a set of light emitting diodes separate from those employed for monitoring the DC operational status of the telephone line.

Abstract: A mechanism for avoiding satellite transponder TWT saturation in an ALPC communication network detects the onset of a lockup condition through an avalanche detector. In response to avalanche detection, those links which have been identified as participating in a downlink fade have their ALPC attenuator settings placed at a minimum level, so that the operating point of the transponder TWT may be reduced below the avalanche threshold. Thereafter, as the fade recedes, those units whose ALPC attenuators have minimum power settings may be restored to normal operation. Because the orderwire which couples link quality data from a received terminal monitor unit to transmitter attenuator control units through the avalanche detection and recovery scheme may itself be impacted by a downlink fade, the foregoing scheme is augmented by a lockup detection and avoidance mechanism through which recovery from an actual lockup may take place.

Abstract: A telephone ringback apparatus includes a microprocessor-controlled communications device which is connectable with telephone equipment contained in a central office, such as a toll trunk facility, having the capability of identifying the number of a calling party. In response to the telephone user dialing a prescribed ringback access code, the apparatus signals the toll trunk facility causing it to transmit a message representative of the number of the telephone from which the user is calling. Upon receipt of this message the telephone number of the calling party is stored. A synthesized voice message is transmitted to the user instructing the user to hang-up. When the apparatus detects that the phone has been placed back on-hook, it proceeds to transmit dialing signals containing the previously stored number of the telephone, causing the calling party's telephone to ring.

Abstract: An interrupt request handling mechanism employs a portion of the address portion of the data processing system's communication bus. All interrupt requests to a processor are handled by an associated interrupt controller that is coupled between the prescribed address lines and the processor. As interrupt requests are received they are temporarily stored in memory. The storage locations of the memory are successively scanned, beginning with the memory address having the highest priority level and proceeding through successively lesser orders of priority locations until an interrupt request has been found. That located "highest" priority level interrupt request that is stored in memory is placed in a buffer register the contents of which are compared, on a continual basis, with the level of the task being executed by the processor.

Abstract: An hybrid array correlator is configured of a cascaded array of individually identical correlator cells, through which a preselectable reference symbol sequence, identifiable with a symbol to be acquired, is successively clocked, from cell to cell and then recirculated back to the beginning or first cell of the array. The physical span of the correlator covers one complete symbol time, with each cell imparting a one-half chip delay to the reference spreading sequence as it is clocked through the correlator. Yet, because of the recirculation of the reference spreading sequence from the last cell back to the first cell, the electrical span of the correlator is effectively infinite or time invariant. An incoming unknown symbol sequence capable of being acquired is applied in parallel to all the cells of the correlator array.

Abstract: An improved ceiling mountable acoustic transducer mountable in a ceiling tile without the cutting of a hole. A pair of elongated members which pierce the ceiling tile are attached to a housing which holds the acoustic transducer. The housing is held in contact with the surface of the ceiling tile by a pair of spring clips which engage the elongated members. The electrical connection of the transducer to an acoustical electrical signal source is made through the elongated members to the acoustic transducer by attachment of leads to the clips.

Abstract: A TTL gate for driving large capacitive loads with minimal current drain of the gate's power supply during the logic low output level is provided. The current drain from the power supply is minimized by a feedback means which becomes active when the logic low output level is reached. The feedback means comprises a current mirror circuit connected between the drive means and the output means of the gate. The drive means also comprises a current mirror circuit.