Eastman-kodak Company

Spin Physics, Inc.

Eastman Technology, Inc.

Lester Electrical of Nebraska, Inc.

Ward M Calaway

Neil J Griffith

Herbert Karsh

Charles E Wright

Fredrick J Jeffers

Daniel J Geyer

Apparatus for effecting the technique includes a subtraction circuit for producing a difference signal by subtracting successive words of the serial bit stream forming the digital signal. A comparator circuit compares the difference signal to a predetermined maximum slew rate limit signals. If the difference signal is greater than the maximum limit signal, then subtraction and comparison is repeated, after shifting the successive words of the digital signal by one bit. This process is repeated until, when the difference no longer exceeds S, synchronization is assumed.

Technique for processing a digital signal having zero overhead sync

A closed loop circuit corrects digital data baseline shift resulting from perturbing interferences. Samples of the signal amplitude are stored at each clock time; and a correction signal is derived from the stored information. The correction signal is subtracted from the data signal to produce a resultant signal that is devoid of baseline shift, such resultant signal being also used to control clock regeneration in a phase locked loop.

Signal correction apparatus

An electrically conductive element is employed in proximity to a thin film magnetic structure. The conductive element has current applied to it which is just sufficient to maintain, by field coupling between the thin film structure and the conductive element, the given magnetic orientation of the thin film structure, this occurring despite the application of a signal field tending to reorient the magnetization of the thin film structure. Such current is, therefore, the analog of the applied signal field and, since the magnetization of the thin film structure, by virtue of induced magnetic feedback, does not appreciably change direction, harmonics of any signal field applied to the thin film structure, and noise, are not manifested in the current analog.

Magnetoresistive head employing field feedback

A high Q magnetic playback head applies its developed signal to the input of a voltage mode circuit. To facilitate equalizer design, the head is resistor-damped. While mere resistor damping reduces the Q of the head, it does so at the expense of the signal-to-noise ratio (SNR) of the head-and-amplifier circuit. To maintain SNR substantially without change, the amplifier employs a large resistance to which negative feedback is applied so the resistance appears as an effective resistance equal to its actual value divided by the amplifier gain. The value of this effective resistance is made to equal the magnetic playback head inductive reactance at the point of resonance, thereby reducing the head Q to approximately 1, and equalizer design is made easier.

Voltage mode amplifier for use with a high Q magnetic head

To prevent reduction in the efficiency of a battery in the wintertime for batteries used on vehicles outdoors, charging runs are automatically initiated in two or three hour intervals which are timed by 10 Hertz (Hz) clock pulses that are applied to a first counter normally used to measure the potential of the battery with the output from a selected terminal of the first counter being applied through a summer-winter switch to a second counter normally used to measure the rate of change of the potential of the battery. When the number of counts have elapsed indicating a two or three hour delay, the output from the second counter initiates a charging run. The summer-winter switch may be manual or temperature-controlled and may include one or more other positions to disconnect the timing circuit or connect a different terminal of the first counter to the second counter to initiate charging runs every two and one-half days during storage of the battery for long periods of time.

Growing community of inventors

Sierra Madre, CA, United States of America

Ward M Calaway