A particle analyzer of the Coulter type has at least one sensing zone arrangement for generating a first train of particle pulses having a first number of particle pulses in response to passage through the sensing zone of a sample containing a plurality of particles to be counted. Generating circuitry is provided for generating a second train of particle pulses having a second number of particle pulses based upon a second sample containing a plurality of particles, or a hypothetical second sample. The second sample has a specific relationship to the first sample defined by one of either the first and second sample volume ratios, the first and second sample dilution ratio and the sensing zone volume ratio. Circuitry coupled to the first sensing zone arrangement and the generating circuitry is operative to mathematically change the first number of particle pulses and mathematically change the second number of particle pulses in the first and second trains of pulses respectively, and is further operative to combine the changed number of first and second pulses in accordance with a particular mathematical formula for providing an error corrected particle pulse count.

A method and circuit is provided for correcting an output signal pulse train received from a digital transducer representing a physical magnitude. In a graph the relationship of pulse frequency versus said magnitude will be illustrated by a straight line which will not, due to various influences, intersect the origin of the graph but will pass on either side thereof. By superimposing (adding or subtracting) correction pulses on the transducer pulses, said line is displaced and caused to intersect the origin, said relationship thus being changed to a directly proportional one. Conditions for proper superimposition are defined and an electronic circuit for fulfilling the conditions in a simple and reliable way is disclosed.

An electronic trip meter with a correction circuit for an automotive vehicle comprises a counter for producing an ouput signal indicative of a measured distance, an error detector for deriving an error factor of the measured distance with respect to a reference distance, a correction circuit for correcting the measured distance by the error factor, and a display circuit for displaying the corrected distance.

A method and circuit is provided for correcting an output signal pulse train received from a digital transducer representing a physical magnitude. The pulse frequency varies proportionally, although not directly proportionally, with said magnitude so that in a graph the relationship will be illustrated by a straight line which will not intersect the origin of the graph but pass on either side thereof. By superimposing (adding or subtracting) correction pulses on the transducer pulses, said line is displaced and caused to intersect the origin. In superimposition, primarily two conditions have to be fulfilled: no correction pulses are sent for superimposition unless a transducer pulse has occurred first, and the correction pulses and transducer pulses are maintained separated in time so as to be clearly distinguishable.

A particle analyzer of the Coulter type has at least first and second sensing zone arrangements, each having substantially the same dimensions and each generating a train of particle pulses in response to passage through the respective sensing zone of a sample containing a plurality of particles to be counted. A summing circuit connected to the output of each sensing zone sums together each of the trains of particle pulses to develop a summed train of pulses. Additional circuitry is connected to each sensing zone and the summing circuitry. This circuitry is operative to change mathematically at least the number of particle pulses in the summed train of particle pulses. The mathematically changed summed train of pulses and the train of pulses from the first and second sensing zones then are accumulated to produce an error corrected particle pulse count.