Giddings & Lewis, LLC

Amca International Corporation

Michael E Larson

John P Conners

Bruce R Beadle

An electrical circuit and method for multiplying an analog input signal by a sinusoidal function having an instantaneous phase specified by a number signaled in binary format. As a sine wave generator, the binary number is supplied by a counter clocked at a multiple of the desired sine wave frequency. The most significant bit of the counter modulates the polarity of or actually constitutes the analog input signal which is then fed to a numerically-controlled attenuator driven by the less significant binary counter outputs. The attenuator has selectively switched resistors with values specifying a sine table of attenuation from 0 to 90 degrees. A particular resistor is selected by an analog multiplexer having paired complementary outputs so that over the range of less significant bit values, a full 180 degrees of the sinusoid is generated. As a sine wave modulator, the polarity of the analog input signal is modulated in a balanced modulator by the most significant bit of the counter, and the balanced modulator output is used as the input to the attenuator.

Digitally-driven sine/cosine generator and modulator

A system for transmitting binary instruction or data words to or from a computer by control from a home base remote from the computer site, and characterized by the entry of signals into the computer or the extraction of signals from the computer performed by apparatus which directly connects to the computer console manual switches and indicator lights. A single telephone line forming two simultaneously active channels transmitting time-spaced pulses in opposite directions, by modems known in the art, is used as the communication link. A special purpose microcomputer directly connected to the main computer console acts figuratively to actuate the console push buttom switches in response to pulse train signals received from home base and representing single bits or multibit words. It returns to the home base a rapidly iterated and updated pulse train representative of the status of all console lights. The system includes another computer at the home base with a duplicate, reflective console like that of the main computer. The apparatus at the home base computer responds to binary messages to the main computer, due to actuation of the reflective console, with the same effect as if it were bing used and observed at the computer site.

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Fond du Lac, WI, United States of America

Michael E Larson