Mechatron Systems, Inc.

Micronics Computers, Inc.

Televideo Systems, Inc.

Frank W Lin

Harvey C Wong

Suhdok D Moon

Sam K Lim

Max I Anzai

Tri S Van

An improved assembly design for a portable computer. A housing has a base member with a plurality of edge guides located along the side portions and a plurality of connector sockets arranged along the inner front portion. A matching circuit board has a plurality of forwardly extending plug margins which mate with the sockets when the board is fully installed in the edge guides. The board carries the main computer system electronic components and a rigid disk memory module. The keyboard assembly, floppy disk memory and power supply are all mounted to the under surface of the housing cover member, and the display panel is mounted to the top of the cover. The design enables quick assembly of the computer, and quick removal of the circuit board for repair.

Portable computer with improved assembly design

A noise blanking circuit for eliminating evidence of noise present in an incoming alternating electrical control signal, such as a shaft encoder or tachometer signal in a servo control circuit, is disclosed. The alternating electrical signal is input to a first input of a shift register having a plurality of outputs. Clock signals having a preselected frequency are input to a second input of the shift register for digitally sampling the alternating electrical signal at the times of occurrence of the clock signals so as to produce digital samples shiftably stored in respective storage locations of the shift register, which are connected to the plurality of outputs of the shift register. The digital samples appearing at predetermined ones of the plurality of outputs of the shift register are input to a logic circuit for producing a first logic state (low state) as an output signal, when a first logic state appears at the predetermined ones of the plurality of outputs of the shift register, and a second logic state (high state) as the output signal, when a second logic state appears at the predetermined ones of the plurality of outputs of the shift register. The selectivity of the noise blanking circuit can be selected by adjusting the clock signal frequency and/or the number of storage locations included in the shift register and/or changing the predetermined ones of the plurality of outputs of the shift register which are input to the logic circuit. Other features are also disclosed.

Method and apparatus for blanking noise present in an alternating

In a rotary printer control system, a dual mode servo for controlling the velocity and position of a rotary print wheel and a print wheel carriage is normally operated at a relatively high gain value. When the servo is switched from the velocity mode to the position mode, the length of time the servo remains in the position mode is monitored and, if this exceeds a predetermined maximum time period, the gain of the servo loop is switched to a relatively low value in order to reduce oscillations of the print wheel or carriage about the HOME position. The gain reduction is accomplished by inserting a supplemental R-C network in parallel with the high gain R-C network, and the range or ratios of the relatively high gain to the relatively low gain values is from about 10 to about 30.

Velocity-position servo with improved gain control

A speed normalization circuit for eliminating the need to fine tune a servomechanism, such as a daisy wheel printer, after manufacture, for example, in order to compensate for speed variations caused by tolerance variations throughout the manufacturing process and evidenced by variations in the actual print wheel speed and the actual carriage speed, is disclosed. In operation, when a restore sequence is called for (power up, remote restore, cover open/resume, check/resume), the carriage is restored to the leftmost home position and is then stepped three times by an identical amount (twelve increments, 1/120 of an inch per increment). The average value of the actual carriage speed for these three movements is determined and a compensation value is selected. If the carriage speed is too slow, the nominal speed value stored in a read only memory look-up table is incremented by a fixed value (i.e., plus one, two, or three units); if the speed is too fast, the nominal speed value is decremented by a fixed value (i.e., minus one, two, or three units). The compensation value is added to the nominal speed value during subsequent actual operation of the servomechanism. For the print wheel, there are two programmed movements upon restore, namely, one half rotation in each direction (one forward, one reverse) for a total of ninety-six increments per movement. The speed compensation value is calculated in the same manner. Other features are also disclosed.

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Los Altos, CA, United States of America

Frank W Lin