Abstract: Improved method and circuit are disclosed for processing pulses of a pulse train such that tails of pulses ("A" pulses) which precede a valid true pulse ("T" pulse) to be processed and/or pile-up pulses ("P" pulses) which are piled up on the tails of preceding "T" pulses are eliminated. To eliminate the tails of an "A" pulse a first signal is produced at the occurrence of a "T" pulse. This first signal simulates the tail of the "A" pulse and it is subtracted from the tail piled up "T" pulse. To eliminate a "P" pulse a second signal is produced, when a "P" pulse piled up on the "T" pulse occurs. This second signal simulates the tail of the "T" pulse which tail is cut off at the occurrence of a "P" pulse. This simulated tail is then processed instead of the true tail of the "T" pulse.

Abstract: A sample transport mechanism is disclosed for conveying test tube samples in an endless path to and then away from a test station. The samples are removably inserted into elongated test tube supports arrayed upon a table in two rows and moveable in a rectangular path. Underlying the table is a plate generally coextensive therewith and having brackets mounting pins projecting above the margin of the table above and below the rows. The sample supports have parallel grooves in their bottom surfaces transverse to the longitudinal axis of the supports, and into which the pins may engage. The plate also has two openings, one square and the other rectangular, and into which are engaged cams. The cams when rotated move the plate in a rectangular path with respect to the table. The spacing of the pin and slots is such that the pins normally engage two diagonally opposite corner trays and move them longitudinally toward the next row by the incremental distance separating two adjacent samples.