Tektronix, Inc.

Coherent, Inc.

Hoffman, Gilbert A.

Birkel, Steven J.

Gilbert A Hoffman

Bob Elkind

Daniel G Baker

Michael S Overton

James L Tallman

Barry A McKibben

Scott E Zink

Kenneth M Ainsworth

Howard A Landsman

Steven J Birkel

Richard J Farmer

Gary Sargeant

A diode-laser is driven by a modulated voltage through a voltage-to-current converter. The modulated voltage has a fixed level determined by an applied fixed bias voltage and a variable level determined by a modulation voltage signal varying between minimum and maximum values. The fixed voltage level corresponds to a threshold level above which the diode-laser would provide laser-output. The modulation voltage signal is monitored and compared with a predetermined set value. If the monitored voltage signal falls below the set value, the modulated voltage is disconnected from the voltage-to-current converter and the output of the diode-laser falls to zero.

Driving circuit for analog-modulated diode-laser

Aspects of the present invention are related, in general, to Type-III phase-locked loops. In particular, aspects of the present invention relate to analog Type-III phase-locked loop arrangements comprising at least two signal paths, wherein each signal path may correspond to a bandwidth partition and may be selected by a selector according to a bandwidth parameter value. According to one aspect of the present invention, a first signal path may correspond to a fast loop (wide closed-loop bandwidth), and a second signal path may correspond to a slow loop (narrow closed-loop bandwidth).

Analog phase-locked loop

A system for phase-locking a clock to a digital audio signal embedded within a digital video signal uses an audio extractor, frequency dividers, and an adjusted bandwidth loop filter to prevent phase jitter associated with the digital audio signal preventing the functionality of the phase-lock loop or having unacceptable effects on the generated audio sample frequency signal. Extracted audio samples are divided down and input to a phase detector. The signal is then filtered using a series of loop filters, one of which has an adjusted bandwidth to reject phase jitter. A clock then outputs the generated synthesized audio sample frequency using the output from the series of loop filters, and the synthesized frequency signal is looped back through a second frequency divider to the phase detector.

System for phase-locking a clock to a digital audio signal embedded in a

A digital audio waveform display is presented on a digital video waveform display instrument using the video waveform display circuitry. A decoder extracts embedded digital audio data from a digital video signal. The digital audio data is stored in a buffer memory. N digital audio data words, corresponding to N samples of the video data representing a video line for display, are read from the buffer memory at a video sample rate and input to the video waveform display circuitry. The video waveform display circuitry includes a digital to analog converter operating at the video sample rate and an analog video reconstruction filter which provides amplitude values for a swept display device.

Digital audio waveform display on a video waveform display instrument

A bright video line select display for a waveform monitor is achieved by storing a selected line from a video frame of a digital video input signal. The stored selected line is iteratively substituted for a plurality of video lines during the vertical interval of the digital video input signal. When line select mode is selected, those video lines during the vertical interval are displayed as a waveform, resulting in a brighter display of the selected video line.

Bright video line select display

A device for simultaneously displaying unrelated signals processes the signals separately prior to inputting them to a multiplexer. Under control of a microprocessor the multiplexer. Under control of a microprocessor the multiplexer switches between the processed signals to alternately pass the signals to the deflection circuits of an X-X display device at a rate which does not interfere with other frequencies used in the environment where the device is used.

Simultaneous display of two unrelated signals

A switching power supply that comprises a base drive transformer, a switch device connected to one end of the transformer's primary winding, and a transistor having its base connected to one end of the secondary winding and its emitter connected to the other end of the secondary winding, also comprises a current-dependent voltage clamp connected across one winding of the transformer. The clamp circuit prevents the voltage across the primary winding from exceeding a predetermined value so long as the magnetizing current that flows in the primary winding when the switch device is opened does not exceed a predetermined value.

Switching power supply with transistor drive circuit

A capacitive goniometer comprises a plurality of like conductive annular sectors supported in mutually substantially coplanar relationship so as to define an axis which extends through the center of the annulus and is substantially perpendicular to the common plan of the sectors. A conductive member having a generally arc rate outer periphery is supported in spaced confronting relationship with the sectors with the outer periphery of the conductive member not extending substantially farther radially of the axis than the sectors, whereby an electrical signal applied to one of the sectors is capacitivity coupled to the conductive member.

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Aloha, OR, United States of America

Gilbert A Hoffman