Abstract: A railcar retarder assembly for use in a railroad trackwork such as a railcar classification yard is provided with a fixed base plate, a vertically-oriented pivot shaft secured to the base plate, an elongated and curved cam member mounted on the pivot shaft, and a horizontally-oriented hydraulic subsystem piston element that induces reaction hydraulic damping forces which are transmitted horizontally to the wheel flanges of a passing railcar to thereby reduce the rolling velocity of the railcar.

Abstract: A two-way audio communication system is designed to allow basic audio communication between two users on a common computer network. The audio communication system of the present invention is designed to work in the background of the computer, so the user can work on other software applications simultaneously. In a half-duplex embodiment (i.e., only one user can talk at a time), if at least two users try to talk at the same time, an arbitration scheme is employed to settle the dispute. The winner of the arbitration can send a message, and the loser's message is discarded. The communication system reduces the time delay between when a message is sent on one end, and received at the other. In addition, the system provides for high quality audio reproduction of the message on the other end by minimizing the number of audible gaps or other artifacts transmitted along with the message.

Abstract: The image dot gain that normally occurs in a printing press is controllably simulated as a separate step in the process of producing accurate color proofs. The simulation is attained by placing a diffuser plate between a high-intensity light source and a color-separated image master along with its corresponding image receptor. By varying the position of the diffuser plate the percentage of image dot gain is accurately controlled as an independent variable without the need to alter the exposure time.

Abstract: A digital-to-analog converter apparatus (DAC) includes internal PROM-controlled compensating converter means for precisely compensating values of lesser significant bits in accordance with scale factors which depend upon the binary input values of more significant bits and which are independent of compensation of the analog output signal value corresponding to the more significant bits. The converter apparatus employs programmable read-only memory (PROM) for decoding input digital values into digital compensation values which control internal digital-to-analog converter apparatus. An analog signal out of an internal compensating digital-to-analog converter apparatus is coupled to a summing junction and an analog scaling reference. The output of the summing junction generates a compensated analog scaling value signal which is fed to a reference terminal of a digital-to-analog converter apparatus which generates the analog signal representing the lesser significant bits.

Abstract: An apparatus for measuring the precise sample mass and corresponding sample weight, being tolerant of and relatively insensitive to unwanted background environmental forces, while functioning independently of the force of gravity, uses a vibratory method and a feedback means to monitor and to sustain the sample mass in oscillation at the mechanical resonant frequency of the system in which the sample mass is introduced. The sample mass is forced to oscillate continuously by electromagnetic action, whereby the resultant motion is transmitted by springs and a transmission structure to supporting piezoelectric transducers. These transducers generate an output voltage signal representative of the sample pan's motion, that is amplified and returned to an electromagnetic drive coil in order to sustain oscillation and maintain the closed-loop nature of this system. These oscillations are monitored and the associated frequency measurements used in calculating the sample mass.