Interpolating apparatus

Claim 2

Interpolating apparatus for dividing a time interval of variable duration into a predetermined integral number, K, of subintervals comprising: signal generating means for providing at least two reference pulses for determining the duration of said time interval; first interpolating means connected to said signal generating means for dividing said interval between said reference pulses into a predetermined integral number, K1, of first subintervals and for providing pulses indicative of each of said first subintervals; and second interpolating means connected to said first interpolating means for subdividing each of said first subintervals into a predetermined integral number, K2, of second subintervals, where K1 multiplied by K2 is equal to K, and for providing pulses indicative of each of said second subintervals.

Claim 3

Interpolating apparatus as defined in claim 1 further including pulse generating means connected to said first and second interpolating means for providing first pulses at a rate f, second pulses at a rate f/K1 to said first interpolating means, and third pulses at a rate of f/K2 to said second interpolating means.

Claim 4

Interpolating apparatus as defined in claim 2 wherein said first interpolating means includes a first counter connected to said signal generating mEans and to said pulse generating means for counting said second pulses for an interval determined by said reference pulses to generate a count M and a first frequency divider connected to said first counter and to said pulse generating means for dividing said first pulses by said count M to provide said pulses indicative of each of said first subintervals, and said second interpolating means includes a second counter connected to said pulse generating means and to said first frequency divider for counting said third pulses for intervals determined by said pulses indicative of said first subintervals to generate a count N for each of said first subintervals and a second frequency divider connected to said second counter and to said pulse generating means for dividing said first pulses by the counts N to provide said pulses indicative of each of said second subintervals.

Claim 5

Interpolating apparatus as defined in claim 3 wherein said first and second frequency dividers include first and second registers connected to said first and second counters, respectively, and third and fourth counters connected to said first and second registers, respectively, and to said pulse generating means whereby said third and fourth counters each count said first pulses in groups equal to the counts M and N, respectively.

Claim 6

Interpolating apparatus as defined in claim 4 wherein said signal generating means is connected to said third counter for resetting said third counter each time a reference pulse occurs, and said third counter is connected to said fourth counter for resetting said fourth counter each time one of said pulses indicative of each of said first subintervals occurs.

Claim 7

Interpolating apparatus as defined in claim 1 wherein the number K is 90.

Claim 8

Interpolating apparatus as defined in claim 6 wherein the number K1 is 15 and the number K2 is 6.

Claim 9

Interpolating apparatus as defined in claim 5 wherein the number K is 90, the number K1 is 15, and the number K2 is 6.

Claim 10

Interpolating apparatus for use in an internal combustion engine control system for dividing time intervals of variable durations between reference pulses provided by a signal generating means representative of numbers of degrees of rotation of the crankshaft of said engine into a predetermined number, K, of subintervals comprising: pulse generating means for providing first pulses at a rate f, second pulses at a rate f/K1 where K1 is a predetermined integer, and third pulses at a rate f/K2 where K2 is a predetermined integer and K1 X K2 K; first interpolating means connected to said pulse generating means and to said signal generating means for dividing each of said time intervals between said reference pulses into K1 first subintervals and for providing pulses indicative of said first subintervals; and second interpolating means connected to said pulse generating means and to said first interpolating means for subdividing each of said first subintervals into K2 second subintervals and for providing pulses indicative of said second subintervals.

Claim 11

Interpolating apparatus for use in an internal combustion engine control system for dividing time intervals of variable durations between reference pulses provided by a signal generating means representative of numbers of degrees of rotation of the crankshaft of said engine into a predetermined number, K, of subintervals comprising: pulse generating means for providing first pulses at a rate f, second pulses at a rate f/K1 where K1 is a predetermined integer, and third pulses at a rate f/K2 where K2 is a predetermined integer and K1 X K2 K; first interpolating means connected to said pulse generating means and to said signal generating means for dividing each of said time intervals between said reference pulses into K1 first subintervals and for providing pulses indicative of said first subintervals; and second interpolating means connected to said pulse generating means and to said first interpolating means for subdividing each of said first subintervals into K2 second subintervals and for providing pulses indicative of said second subintervals.

Claim 12

Interpolating apparatus as defined in claim 9 wherein said first interpolating means includes a first counter connected to said signal generating means and to said pulse generating means for counting said second pulses for time intervals determined by said reference pulses to generate a count, M, for each of said time intervals and a first frequency divider connected to said first counter and to said pulse generating means for dividing the rate of said first pulses by said count M, and said second interpolating means includes a second counter connected to said first frequency divider and to said pulse generating means for counting said third pulses for said first subintervals deteRmined by pulses provided by said first frequency divider to generate a count, N, for each of said first subintervals and a second frequency divider connected to said second counter and to said pulse generating means for dividing the rate of said first pulses by said count N.

Claim 13

Interpolating apparatus as defined in claim 10 wherein said first frequency divider includes a third counter connected to receive said count M and said first pulses for counting said first pulses in groups of M pulses, and said second frequency divider includes a fourth counter connected to receive said count N and said first pulses for counting said first pulses in groups of N pulses.

Claim 14

Interpolating apparatus as defined in claim 11 wherein said signal generating means is connected to said third counter for synchronizing the start of said third counter with said reference pulses, and said third counter is connected to said fourth counter for synchronizing the start of said fourth counter with pulses provided by said third counter.

Claim 15

Interpolating apparatus as defined in claim 12 wherein K is 90, K1 is 15, and K2 is 6.

Claim 16

Interpolating apparatus as defined in claim 9 wherein K is 90, K1 is 15, and K 2 is 6.