Abstract: An optical disc system for storing information on a medium includes a light source, a focusing mechanism, and a tracking mechanism wherein the mechanisms are controlled by a feedback loop and the focusing mechanism focuses light emitted by the light source onto the medium to effect writing of information thereon. The system is provided with an electronic circuit for generating a servo error signal that is communicated in the feedback loop for effecting corrections of the focusing mechanism and the tracking mechanism. The system is further provided with a driver for energizing the light source, a bias coil disposed proximate to the medium, a bias coil driver switchably connected to the bias coil for supplying an electric current thereto, a current monitoring circuit connected to the bias coil driver having an output responsive to the electric current, and a controller connected to the output of the current monitoring circuit and to the driver.

Abstract: An analog to digital circuit assembly includes a circuit for multiplexing a reference voltage input of an analog to digital converter to produce alternating normalized and referenced digital outputs of an analog signal input at a rate controlled by a sampling clock which includes a switch including first and second inputs, an output, and a control input for alternately connecting the first and the second inputs to the output, the output being applied to the reference voltage input. An information detection device having a detection output and a servo mechanism that controls operations on detected information is provided in conjunction with a signal summing circuit, a direct current voltage reference, a control clock connected, a servo error signal circuit having a servo error signal output and input, a sampling clock, and a processing circuit having an input connected to a digital output of the analog to digital converter and an output for controlling the servo mechanism.

Abstract: A class of predominantly hydrophilic 1,8-naphthalimide dyes. The dye contains at least two 1,8-naphthalimide ring systems, joined by a spacer moiety. Each of the 1,8-naphthalimide ring system has a ring nitrogen atom and bears, at the 4 position, an amino nitrogen atom, carrying a hydrogen. The remaining unsatisfied valences, if present, of the ring nitrogen atoms or the amino nitrogen atoms, or all, are occupied by one or more alkyl substituents. Each of the 1,8-naphthalimide ring system is free of an azo substituent and is also free of a nucleofuge. Upon activation by an activating agent in an environment independent of the presence or absence of oxygen, these compounds generate activated species. The activated species can cause structural changes in lipid and any associated proteins and polypeptides, extra- or intra-cellular or transmembrane, leading to polymerization and crosslinking.

Abstract: The use of a highly acidic metalated organic acid composition (“HAMO”) as a food additive. The HAMO is used to reduce biological contaminants, and thus preserve, a nutriment. The HAMO is being absorbed in, or adsorbed on, a nutriment material to give a prepared nutriment.

Abstract: A protection circuit (30) for a Traveling Wave Tube having multiple tone operation. The protection circuit (30) is a dual sensor (52, 54) arrangement. One sensor (52) is an operational amplifier circuit (56) having a short time constant and a high threshold current. The first sensor (52) provides protection against short time scale faults. The second sensor (54) is an operational amplifier circuit (58) having a time constant higher than the first sensor (52) and a lower current threshold than the first sensor (52) to provide protection against long time scale events. The two sensors (52 and 54) are logically “OR”ed with each other and eliminate spurious shutdowns and circuit damage.

Abstract: An optical drive system includes a computer that monitors the current in an improved bias coil assembly in conjunction with a magnetomotive field generator to determine when a predetermined current threshold is exceeded. The bias coil assembly includes a wire coil wrapped around a center bar contained by a bias coil housing. The bias coil assembly is positionable above an information storage medium so that the entire medium may be within the magnetic field thereby allowing writing of information to all portions of the medium. When the threshold is exceeded, a sufficiently strong magnetic field is generated to permit writing of information on the storage medium utilizing a laser. A laser pulse generator is then enabled. The device thereby achieves a substantially shortened write cycle while employing the improved bias coil assembly.

Abstract: A method for moving an optical head from an initial track to a target track on a storage medium having data arranged in tracks thereon. The method includes determining a track crossing number indicating a number of tracks between the initial track and the target track, moving the optical head from the initial track toward the target track, and measuring a reflectivity level of light from the medium. The method continues with deriving a tracking error signal responsive to the reflectivity level. A waveform of the tracking error signal has zero crossings corresponding to the optical head crossing one of the tracks. The method may further include incrementing a track count number for each the zero crossing, and passing the reflectivity level through a high pass filter to obtain a data indicator signal. In this embodiment, a waveform of the data indicator signal has indicator points corresponding to the zero crossings.

Abstract: An optical drive system includes a computer that monitors the current in the bias coil of a magnetomotive field generator to determine when a predetermined current threshold is exceeded. When the threshold is exceeded, a sufficiently strong magnetic field is generated to permit writing of information on a storage medium utilizing a laser. A laser pulse generator is then enabled. The system is provided with an optics module for processing light produced by the laser light source. A laser driver for energizing the laser light source is positioned in close proximity to the optics module and the laser light source to reduce noise in signals associated with the optics module. The system thereby achieves a substantially shortened write cycle while reducing relevant signal noise.

Abstract: An analog to digital circuit assembly for use in an optical information includes a circuit for multiplexing a reference voltage input of an analog to digital converter to produce alternating normalized and referenced digital outputs of a plurality of analog signal inputs at a rate controlled by a sampling clock which includes a switch including first and second inputs, an output, and a control input for alternately connecting the first and the second inputs to the output, the output being applied to the reference voltage input.

Abstract: The present invention provides, a 3 or 4-amino-1,8-naphthalimide compound having polyether substituent groups at the 3 or 4-position and the imide position. The polyether groups are linked to a hydrocarbon directly linked at the 3 or 4-amino position and the imide position. The polyether groups render the 3 or 4-amino-1,8-naphthalimide compound sufficiently soluble in a fluid such that visualization of the fluid by color or fluoresence is allowed. In one advantageous embodiment, the 3 or 4-amino-1,8-naphthalimide is obtained from the mixture of 4-chloro-1,8-naphthalic anhydride with monoamine polyether.

Abstract: An optical drive system includes an optical assembly, a light source, a lens positioned to direct light between the optical assembly and an information storage medium or disc, and an actuator suspending the lens. A photodetector is disposed in a path of returning light to measure light received from the medium. A monitoring circuit is provided to monitor a Quad Sum signal associated with return light. A first servomotor is employed to move the lens in a tracking direction and to move the lens during focus capture while system circuitry searches for a maximum Quad Sum signal. A second servomotor is employed to move the lens in a focusing direction. A first electronic circuit is provided to control the first and second servomotors.

Abstract: A magneto-optical drive system having a computer that monitors the current in the bias coil of a magnetomotive field generator to determine when a predetermined current threshold is exceeded. When the threshold is exceeded, a sufficiently strong magnetic field is generated to permit writing of information on a storage medium utilizing a laser. A laser pulse generator is then enabled. The device thereby achieves a substantially shortened write cycle.

Abstract: A mechanical isolation apparatus suited for mitigating the effects of undesired mechanical forces upon disc drive system components, such as those found in compact disc, laser disc, magneto-optical player/recorder devices and similar devices. Component members are provided for mitigating the effects of compressive forces, vibration isolation, and thermal expansion, and may include compression ribs mounted on a housing for absorbing compressive forces. The housing is preferably adapted to fit on the end of a pole piece assembly. A crash stop may also be provided as a shock absorbing bumper and isolator to prevent a moving carriage from crashing into a solid surface. The compressive ribs and the crash stop are made of a material that exhibits minimum creep, such as a silicon rubber, polyurethane, or injection molded plastic.

Abstract: An optical disc drive system is employed in conjunction with a storage medium having a plurality of data sectors each provided with a header and a data storage area. The system includes a data detection device for retrieving stored data from the storage medium and outputting a data signal, an amplifier for providing a variable gain to the data signal and outputting an amplified data signal, a detector that is responsive to the amplified data signal for evaluating a predetermined one of the sectors to ascertain whether the storage area is blank, and an automatic gain control circuit producing a gain control output for controlling the gain of the amplifier. The control circuit has a first mode and a second mode, the first mode being active during retrieval of the header and the second mode being active during retrieval of the data storage area.

Abstract: An optical drive system includes an objective lens subassembly for directing light from a light source toward an information storage medium. An amount of the directed lighted light is returned from the storage medium. An objective lens is disposed in the objective lens subassembly. A first servomotor moves, during focus capture, the objective lens to a first position, away from the first position toward the storage medium being read while looking for a maximum Quad Sum signal, and back away from the storage medium. An electronic control circuit is connected to the first servomotor. A servo error detector is coupled to the electronic control circuit and disposed in a path of light returning from the information storage medium.

Abstract: A class of predominantly hydrophilic 1,8-naphthalimide dyes. The dye contains at least two 1,8-naphthalimide ring systems, joined by a spacer moiety. Each of the 1,8-naphthalimide ring system has a ring nitrogen atom and bears, at the 4 position, an amino nitrogen atom, carrying a hydrogen. The remaining unsatisfied valences, if present, of the ring nitrogen atoms or the amino nitrogen atoms, or all, are occupied by one or more alkyl substituents. Each of the 1,8-naphthalimide ring system is free of an azo substituent and is also free of a nucleofuge. Upon activation by an activating agent in an environment independent of the presence or absence of oxygen, these compounds generate activated species. The activated species can cause structural changes in lipid and any associated proteins and polypeptides, extra- or intra-cellular or transmembrane, leading to polymerization and crosslinking.

Abstract: A method of testing a semiconductor memory device using a parallel march pattern method of testing. All of the memory bits in a memory device are programmed to a first logic state. All of the memory bits in selected rows are programmed to a second logic state. All of the memory bits in rows adjacent to the rows programmed to the second logic state are read to determine if the memory bits programmed to the second logic state have caused the memory bits programmed to the first logic state in the adjacent rows to change logic state. The selected rows are determined by a periodicity value that can be values such as 4, 8, or 16. The periodicity determines the number of clock cycles needed to test the entire memory device. A periodicity of 8 requires only 8 clock cycles to test the entire memory device, regardless of the size of the memory device. The parallel march pattern method of testing can be by rows, by columns or by diagonals.

Abstract: A laser driver for controlling an electrical current supplied to a laser in an optical disc system. The laser driver includes pass transistors for delivering electrical current to the laser, an operational amplifier for setting a reference voltage on the bases of the pass transistors, and a CMOS buffer for applying a drive voltage to emitter circuits of the pass transistors. The drive voltage has a first voltage level and a second voltage level, and the electrical current is supplied to the emitter circuits only when the drive voltage is at the first voltage level. The laser driver further includes a switch for switching the drive voltage between the first voltage level and the second voltage level so that electrical power is consumed only when the laser is energized and enhanced rise and fall switching characteristics are thereby achieved.

Abstract: An optical disc system using CMOS logic as part of a power driver assembly is employed to actually switch electrical currents to a system laser so that power is consumed more efficiently, thermal problems are mitigated, and very fast rise and falls times are achieved.

Abstract: A class of predominantly hydrophobic non-azo N-substituted 1,8-naphthalimide compounds, each bearing, at its 3-position, a nucleofuge and, at its 4-position, a heteroatomic electron-releasing group. The heteroatomic electron-releasing group is being characterized as having a heteroatom directly linked to the 4-position of the ring, and having at least one hydrogen directly attached to the heteroatom. Upon activation by an activating agent in an environment independent of the presence or absence of oxygen, these compounds generate activated species. The activated species initiate chemical changes in lipid bilayer membranes of viruses and other target cells. These changes can eradicate viruses and other target cells. The activated species can also cause structural changes in lipid and any associated proteins and polypeptides at a level beneath the surface of the membrane, leading to polymerization and crosslinking.