Sony/tektronix Corporation

Tektronix, Inc.

Tektronix International Sales Gmbh

Ryoichi Sakai

Hisashi Tamamura

Hisao Takahashi

Toru Takai

Hideaki Okuda

Fujihiko Omiya

Yasumasa Fujisawa

Iwao Akiyama

A waveform generator has a waveform generation circuit storing waveform data for an analog waveform signals having dead time periods without the need for storing data on the dead time. A sequencer having a sequence memory stores sequence data that controls the sequencing of one or more signal components and associated dead times of the analog waveform signal. The timing of the dead time is controlled by a sampling clock and a wait time counter. The generation of the signal components is controlled by the sampling clock controlling the generation of addresses for a waveform memory storing digital data of the sampling components. The waveform memory digital data is converted to an analog waveform signal.

Waveform generation circuit for a waveform generator

A jitter inducing circuit receives a reference pulse train and induces desired amounts of jitter to the rising and/or falling edges of the pulses. First and second delay blocksandalternately delay the selected edge or edges of the provided reference pulse train interval by preset delay times for every interval. A signal composercomposes the outputs of the first and second delay blocksand. A delay time setup circuit controls the delay times of the delay blocksand. The delay times may change for each interval as a function of time so as to trace a desired function such as a sinusoidal or triangular function.

Circuit and method for inducing jitter to a signal

A DDS type variable frequency signal generator generates a jitter free and stable output signal regardless of the address interval. If the total number of addressable memory locations of a memory storing digital data is divisible without remainder by an initial address interval, then the memory is read every initial address interval with a clock signal of a predetermined frequency. If the total number of addressable memory locations is not divisible without remainder by the initial address interval, then the address interval is modified to a value that is divisible without remainder into the total number of addressable memory locations and the clock frequency is modified in accordance with this modification of the address interval. The memory is read every modified address interval with the modified clock signal.

Variable frequency signal generating method

An electronic device measurement apparatus measures a characteristic of an electronic device under test (DUT) by applying a sine-wave voltage to the DUT, detecting the voltage across the DUT as well as the current flowing through the DUT and displaying a characteristic curve in accordance with the detected voltage and current. The sine-wave voltage is generated in phase with an AC line voltage but the amplitude thereof is independent of the line voltage, and consequently the circuits in the measurement apparatus are not affected by variations in phase and amplitude in the line. Moreover, the generated sine-wave voltage is symmetrical, whereby display distortion is substantially eliminated. A voltage limiter and a current limiter are provided for limiting the voltage and current to be applied to the DUT to values determined by a display window, for protecting a current detecting resistor and a voltage divider connected to the DUT.

Apparatus for measuring characteristics or electronic devices

A temperature compensated amplifier network for a fiber optical receiver includes a photodiode having an optical input and a current output, and a cascadable transimpedance amplifier having N stages, each stage having a common base-emitter voltage. An emitter-follower transistor is coupled to the last stage of the transimpedance amplifier network and has a base-emitter voltage of the same magnitude but of opposite polarity from the base-emitter voltage of each of the amplifier stages. Any DC drift of the amplifier stages is therefore offset by a compensating drift in the opposite direction by the output emitter-follower.

Growing community of inventors

Yokohama, Japan

Ryoichi Sakai