US3900850A — Digital pulse train tracker

Claim 1

Independent Claim 458 words

A pulse train tracking system for selectively tracking pulse trains derived from a signal input of composite pulse trains wherein successive pulses of a given train are separated by substantially equal inter-pulse periods, comprising: first means responsive to a master clock pulse train for digitally measuring the inter-pulse period between a given pulse of said signal input and a successive pulse thereof received within an interval of predetermined minimum and maximum inter-pulse periods after said given pulse, a plurality of second means responsive to said input signal for selectively and independently different respective trains of pulses, and each of said second means being responsive to the inter-pulse period measurement of said first means for establishing a prediction of the inter-pulse period in accordance with the master clock pulse rate and a gate defined by a predetermined number of master clock pulses within which is predicted the occurrence of the next successive pulse of a train including the given and successive pulses for tracking of that train, said first means being operative to effect said digital measurement for each of a plurality of sets of said given and successive pulses in said input signal, in sequence, and available ones of said second means are selectively rendered responsive to said measurements by said first means for independently tracking of the corresponding trains of pulses, third means responsive to an error between the predicted and actual occurrences of each of successive pulses of that train received within corresponding, successive ones of said gates, said third means controlling said second means to effect a corresponding correction in the prediction by said second means of the occurrence of the respectively next successive pulses, said third means including quantizing means responsive to said digital error measurements to produce a digital correction signal in response to receipt and accumulation of a predetermined number of master clock pulses corresponding to said measurements, said first means also including means to compare inter-pulse periods and establish a prediction of the inter-pulse period of a pulse train to be tracked, said third means also effecting measurement, at the master clock pulse rate, the magnitude of said errors between said predicted and actual occurrences of said successive pulses of said train of pulses and producing a digital correction signal in response to said digital error measurements, said first means also being responsive to the digital correction signal of said third means for effecting a correction of the prediction of the inter-pulse period of the train of pulses being tracked and said first means being responsive to receipt of a first pulse from said input preceding said given pulse by an inter-pulse period substantially equal to the inter-pulse period measured between said given and successive pulses for effecting said digital measurement.

Claim 2

Dependent Claim 458 words

A pulse train tracking system for selectively tracking pulse trains derived from a signal input of composite pulse trains wherein successive pulses of a given train are separated by substantially equal inter-pulse periods, comprising: first means responsive to a master clock pulse train for digitally measuring the inter-pulse period between a given pulse of said signal input and a successive pulse thereof received within an interval of predetermined minimum and maximum inter-pulse periods after said given pulse, a plurality of second means responsive to said input signal for selectively and independently different respective trains of pulses, and each of said second means being responsive to the inter-pulse period measurement of said first means for establishing a prediction of the inter-pulse period in accordance with the master clock pulse rate and a gate defined by a predetermined number of master clock pulses within which is predicted the occurrence of the next successive pulse of a train including the given and successive pulses for tracking of that train, said first means being operative to effect said digital measurement for each of a plurality of sets of said given and successive pulses in said input signal, in sequence, and available ones of said second means are selectively rendered responsive to said measurements by said first means for independently tracking of the corresponding trains of pulses, third means responsive to an error between the predicted and actual occurrences of each of successive pulses of that train received within corresponding, successive ones of said gates, said third means controlling said second means to effect a corresponding correction in the prediction by said second means of the occurrence of the respectively next successive pulses, said third means including quantizing means responsive to said digital error measurements to produce a digital correction signal in response to receipt and accumulation of a predetermined number of master clock pulses corresponding to said measurements, said first means also including means to compare inter-pulse periods and establish a prediction of the inter-pulse period of a pulse train to be tracked, said third means also effecting measurement, at the master clock pulse rate, the magnitude of said errors between said predicted and actual occurrences of said successive pulses of said train of pulses and producing a digital correction signal in response to said digital error measurements, said first means also being responsive to the digital correction signal of said third means for effecting a correction of the prediction of the inter-pulse period of the train of pulses being tracked and said first means being responsive to receipt of a first pulse from said input preceding said given pulse by an inter-pulse period substantially equal to the inter-pulse period measured between said given and successive pulses for effecting said digital measurement.

Claim 3

Dependent Claim 48 words

A pulse train tracking system as recited in claim 1 wherein each of said second means is operable to disable said first means from effecting such digital measurement with respect to pulses in said signal input of a train currently being tracked by one of said second means.

Claim 4

Dependent Claim 66 words

A pulse train tracking system as recited in claim 2 wherein there is further provided assignment means responsive to the tracking operations of each of said second means for identifying available and busy ones of said second means and for selectively assigning available ones of said second means for responding to said digital measurements of said first means for sequential assignment thereof for tracking of trains.

Claim 5

Dependent Claim 72 words

A pulse train tracking system as recited in claim 1 wherein said first means comprises a first digital counter responsive to a pulse train from a master clock pulse source and to receipt of a given pulse of said signal input to accumulate a count at a rate in accordance with said master clock pulse train until receipt of the successive pulse for effecting said digital measurement of the inter-pulse period therebetween.

Claim 6

Dependent Claim 99 words

A pulse train tracking system as recited in claim 4 wherein: said second means includes a count down digital counter responsive to the count accumulation of said first means in a jam transfer of said count accumulation of said first means to said second means following receipt of said successive pulse and responsive to said master clock pulse rate to count down from said transferred accumulated count, said second means including decoder means associated with said counter and responsive to the countdown operation thereof to establish said gate as a predetermined number of counts preceding a count of zero.

Claim 7

Dependent Claim 182 words

A pulse train tracking system as recited in claim 5 wherein: said third means includes a digital phase counter having prestored therein a predetermined count selected in accordance with the number of master clock pulses corresponding to said gate and responsive to a clock pulse rate to count down from said prestored count to zero, and said third means controls said phase counter thereof in the absence of a pulse within one of said gates to count down to zero at a rate in accordance with a nominal time period following the gate end to effect said jam transfer at the count of zero and in response to receipt of a pulse within said gate to initiate count down of said counter simultaneously therewith and to effect count down to zero at a time related to said nominal time by an amount corresponding to the error between the predicted and actual occurrences of the pulse within the gate to effect said jam transfer at a time to correct for said error in the prediction of the occurrence of each next successive pulse.

Claim 8

Dependent Claim 175 words

A pulse train tracking system as recited in claim 6 wherein: said third means further includes first and second quantizing means and corresponding first and second gating means, said gating means being responsive to the occurrence of a signal pulse within said gate and to the count down operation of said phase counter of said third means for gating clock pulses to said first quantizing means for a time interval equal to the time interval by which the actual occurrence of a pulse precedes the predicted occurrence thereof, and to said late quantizing means for a time interval by which the actual occurrence of a pulse follows the predicted occurrence thereof, and said digital counter of said first means is conditioned by said first and second gating means of said third means to count alternatively in up and down directions, respectively, and responds to the outputs of said first and second quantizing means of said third means to count in the conditioned directions by the quantized count outputs of said first and second quantizing means.

Claim 9

Dependent Claim 333 words

A pulse train tracking system as recited in claim 1 wherein said first means further comprises: a digital counter responsive to a train of master clock pulses from a master clock pulse source and to receipt of a pulse from said signal input to initiate counting in response to the master clock pulses, sAid counter including first decoder means establishing a first interval of predetermined minimum and maximum inter-pulse periods subsequent to initiation of counting, and second decoder means establishing a second interval of predetermined minimum and maximum inter-pulse periods subsequent to said first interval, in accordance with accumulation of predetermined numbers of counts corresponding to said periods, storage means controlled by said first decoder of said counter to be enabled during said first interval for individually identifiable storage of pulses from said signal input occurring during said first interval, said storage being effected at a first clock pulse rate synchronized to the master clock pulse rate, and said storage means being responsive to said second decoder for read out of the pulse storage therein during said second interval at a second clock pulse rate of one-half of said first clock pulse rate and synchronized to the master clock pulse rate, and comparison means responsive to said storage means and to signal pulses from said signal input received during said second interval for comparison of the said signal pulses received from said signal input during said second interval with the storage pulses read out from said storage means during said second interval, said comparison means producing an output signal for establishing tracking of a train including said first, said given, and said successive pulses when a successive pulse received from said signal input is coincident with a storage pulse read out from said storage means during said second interval and thus when the inter-pulse period of said given pulse and said successive pulse is equal to the inter-pulse period of said given pulse and said first pulse which initiated counting by said counter.

Claim 10

Dependent Claim 421 words

In a pulse train tracking system having acquisition means which identify and acquire pulse trains, in succession, from a signal input of composite pulse trains and having a plurality of tracking means individually assigned for selectively tracking pulse trains acquired by said acquisition means from the signal input, to which said tracking means are individually and selectively assigned for tracking thereof, wherein in each such pulse successive pulses are separated by substantially equal inter-pulse periods, and wherein the inter-pulse periods of successive pulses is predicted and the occurrence of each successive pulse is predicted within a gate with the leading edge of the pulse at the gate center, the improvement comprising: a first digital counter responsive to a source of master clock pulses and a pulse received from said signal input to initiate counting in response to master clock pulses, said first counter including first and second decoders establishing a first interval of predetermined minimum and maximum inter-pulse periods relative to the initiation of counting by said first counter and third and fourth decoders establishing a second interval of predetermined minimum and maximum inter-pulse periods relative to said first interval, in accordance with predetermined counts corresponding to each of said periods, storage means controlled by said first decoder of said counter to be enabled during said first interval for individually identifiable storage of pulses from said signal input occurring during said first interval, said storage being effected at a first clock pulse rate synchronized to the master clock pulse rate and said storage means being responsive to said second decoder for read out of the pulse storage therein during said second interval at a second clock pulse rate of one half said first clock pulse rate and synchronized to the master clock pulse rate, comparison means responsive to said storage means and to said signal input for comparing pulses received from said signal input during said second interval with the storage pulses read out from said storage means during said second interval to generate a tracking signal upon coincidence of said compared pulseS, representing receipt of three successive pulses having equal inter-pulse intervals, for initiating tracking of the pulse train including the said pulses, and said acquisition means providing a controlled digital measurement of the inter-pulse period of the said pulses in relation to said master clock pulse rate in accordance with said count of said predetermined minimum inter-pulse period of said first interval and the occurrence of the tracking signal relative to the minimum inter-pulse period of said second interval.

Claim 11

Dependent Claim 421 words

In a pulse train tracking system having acquisition means which identify and acquire pulse trains, in succession, from a signal input of composite pulse trains and having a plurality of tracking means individually assigned for selectively tracking pulse trains acquired by said acquisition means from the signal input, to which said tracking means are individually and selectively assigned for tracking thereof, wherein in each such pulse successive pulses are separated by substantially equal inter-pulse periods, and wherein the inter-pulse periods of successive pulses is predicted and the occurrence of each successive pulse is predicted within a gate with the leading edge of the pulse at the gate center, the improvement comprising: a first digital counter responsive to a source of master clock pulses and a pulse received from said signal input to initiate counting in response to master clock pulses, said first counter including first and second decoders establishing a first interval of predetermined minimum and maximum inter-pulse periods relative to the initiation of counting by said first counter and third and fourth decoders establishing a second interval of predetermined minimum and maximum inter-pulse periods relative to said first interval, in accordance with predetermined counts corresponding to each of said periods, storage means controlled by said first decoder of said counter to be enabled during said first interval for individually identifiable storage of pulses from said signal input occurring during said first interval, said storage being effected at a first clock pulse rate synchronized to the master clock pulse rate and said storage means being responsive to said second decoder for read out of the pulse storage therein during said second interval at a second clock pulse rate of one half said first clock pulse rate and synchronized to the master clock pulse rate, comparison means responsive to said storage means and to said signal input for comparing pulses received from said signal input during said second interval with the storage pulses read out from said storage means during said second interval to generate a tracking signal upon coincidence of said compared pulseS, representing receipt of three successive pulses having equal inter-pulse intervals, for initiating tracking of the pulse train including the said pulses, and said acquisition means providing a controlled digital measurement of the inter-pulse period of the said pulses in relation to said master clock pulse rate in accordance with said count of said predetermined minimum inter-pulse period of said first interval and the occurrence of the tracking signal relative to the minimum inter-pulse period of said second interval.

Claim 12

Dependent Claim 264 words

In a pulse train tracking system as recited in claim 9, the improvement further comprising: a storage counter and a count down counter in each of said tracking means, said storage counter being controlled by said acquisition means and in response to said source of master clock pulses to accumulate a count in accordance with the inter-pulse period measurement control of said acquisition means, said count down counter receiving in a jam transfer, a controlled time period subsequent to receipt of each pulse of a train being tracked, the count accumulated by said storage counter to establish a prediction of the inter-pulse period of the train being tracked thereby, said count down counter further including gate start and gate end decoders defining a gate as a number of master clock pulse counts between a predetermined count and zero count of said count down counter within which is predicted the occurrence of the next successive pulse of a train being tracked by said tracking means with the leading edge thereof at gate center, and transfer control means, responsive to the occurrence of said gate to effect said jam transfer a nominal time period after the gate end, said transfer control means including error correction means responsive to the occurrence of a pulse within said gate to effect said jam transfer at a time prior to or following said nominal time period by an amount equal to the amount by which the actual occurrence of the leading edge of the pulse received within said gate precedes or follows, respectively, the predicted occurrence thereof at gate center.

Claim 13

Dependent Claim 152 words

In a pulse train tracking system as recited in claim 10, the improvement further comprising: gating means responsive to said third decoder of said first digital counter for initiating counting of said storage counter of said tracking means simultaneously with enabling of said third decoder at a rate equal to one-half of said master clock pulse rate, said storage counter has prestored therein prior to each tracking operation a count equal to the count of the minimum inter-pulse period of said first digital counter less a count of one-half of the count of said gate, and said transfer control means is operative to effect said jam transfer a nominal time period equal to one-half of the gate count at the master clock pulse rate following the gate end whereby the next successive pulse following initiation of tracking is predicted to occur with the leading edge thereof in coincidence with the gate center.

Claim 14

Dependent Claim 205 words

In a pulse train tracking system as recited in claim 11 wherein said transfer control means further comprises: a phase counter having prestored therein a count equal to the count of said gate, gate means for selectively gating clock pulses to said phase counter for effecting count down selectively at the master clock pulse rate and at twice the master clock pulse rate. said phase counter includes a zero count decoder responsive to count down of said phase counter to a count of zero for producing a transfer signal effecting said jam transfer, and said gate means is responsive to the output of said gate end decoder in the absence of a pulse predicted to occur within a gate for initiating at gate end, count down of said phase counter at twice the master clock pulse rate to effect said jam transfer at said nominal time period following gate end and being responsive to the occurrence of a pulse within said gate for initiating substantiallY simultaneously with the leading edge thereof, count down of said phase counter at the master clock pulse rate for effecting said jam transfer one gate period following the actual occurrence of the leading edge of said pulse within said gate.

Claim 15

Dependent Claim 292 words

In a pulse train tracking system as recited in claim 12, the improvement further comprising: early and late gating means and early and late counters respectively associated therewith, said phase counter includes a 1/2 gate count decoder defining a first half of the gate as an early gate and the last half of the gate as a late gate, said early gating means is responsive to an output from said 1/2 gate count decoder of said phase counter and to an output from the gate and decoder of said count down counter to establish an interval in which master clock pulses are gated to said early counter in response to the actual occurrence of a pulse in the early gate as a digital measurement of the error between the actual occurrence of the leading edge of that pulse and the predicted occurrence thereof at gate center, said late gating means being responsive to an output from the gate end decoder of said count down counter and the zero count decoder of said phase counter to establish an interval in which master clock pulses are gated to said late counter in response to the actual occurrence of a pulse in the late gate as a digital measurement of the error between the predicted occurrence of the leading edge of that pulse at the gate center and the actual occurrence thereof, said early and late counters each including full count decoders providing an error correction pulse to said storage counter, and said storage counter being conditioned by said gating means to count in up or down directions by an amount in accordance with correction signals from said full decoders of said early and late counters, respectively, to correct errors in the predicted inter-pulse period.

Claim 16

Dependent Claim 396 words

In a pulse train tracking system having acquisition means which identify and acquire pulse trains from a signal input of composite pulse trains and having tracking means for selectively tracking a pulse train acquired by said acquisition means from the signal input, wherein in each such pulse train successive pulses are separated by substantially equal inter-pulse periods and wherein the inter-pulse period of successive pulses is predicted and the occurrence of each successive pulse is predicted within a gate with the center of the pulse at the gate center, the improvement comprising: a first digital counter responsive to a source of master clock pulses and a first pulse received from said signal input to initiate counting in response to master clock pulses, said first counter including first and second decoders establishing an interval of predetermined minimum and maximum inter-pulse periods relative to the initiation of counting by said first counter in accordance with predetermined counts corresponding to each of said periods, said first counter accumulating a count at the master clock pulse rate from receipt of said first pulse to receipt of a pulse within said interval, a count down counter receiving in a jam transfer, a controlled time period subsequent to receipt of said pulse within said interval, the count accumulated by said first counter to establish a prediction of the inter-pulse period of the train being tracked thereby, said count down counter further including gate start, gate center, and gate end decoders, said gate start and gate end decoders defining a gate as a number of master clock pulse counts between a predetermined count and zero count of said count down counter and said gate center decoder defining the center of said gate at which is predicted the occurrence of the center of the next successive pulse of a train being tracked by said tracking means, and transfer control means, responsive to the occurrence of said gate to effect said jam transfer a nominal time period after the gate end, said transfer conTrol means being responsive to the occurrence of a pulse within said gate to effect said jam transfer at a time prior to or following said nominal time period by an amount equal to the amount by which the actual occurrence of the center of the pulse received within said gate receives or follows, respectively, the predicted occurrence thereof at gate center.

Claim 17

Dependent Claim 396 words

In a pulse train tracking system having acquisition means which identify and acquire pulse trains from a signal input of composite pulse trains and having tracking means for selectively tracking a pulse train acquired by said acquisition means from the signal input, wherein in each such pulse train successive pulses are separated by substantially equal inter-pulse periods and wherein the inter-pulse period of successive pulses is predicted and the occurrence of each successive pulse is predicted within a gate with the center of the pulse at the gate center, the improvement comprising: a first digital counter responsive to a source of master clock pulses and a first pulse received from said signal input to initiate counting in response to master clock pulses, said first counter including first and second decoders establishing an interval of predetermined minimum and maximum inter-pulse periods relative to the initiation of counting by said first counter in accordance with predetermined counts corresponding to each of said periods, said first counter accumulating a count at the master clock pulse rate from receipt of said first pulse to receipt of a pulse within said interval, a count down counter receiving in a jam transfer, a controlled time period subsequent to receipt of said pulse within said interval, the count accumulated by said first counter to establish a prediction of the inter-pulse period of the train being tracked thereby, said count down counter further including gate start, gate center, and gate end decoders, said gate start and gate end decoders defining a gate as a number of master clock pulse counts between a predetermined count and zero count of said count down counter and said gate center decoder defining the center of said gate at which is predicted the occurrence of the center of the next successive pulse of a train being tracked by said tracking means, and transfer control means, responsive to the occurrence of said gate to effect said jam transfer a nominal time period after the gate end, said transfer conTrol means being responsive to the occurrence of a pulse within said gate to effect said jam transfer at a time prior to or following said nominal time period by an amount equal to the amount by which the actual occurrence of the center of the pulse received within said gate receives or follows, respectively, the predicted occurrence thereof at gate center.

Claim 18

Dependent Claim 142 words

In a pulse train tracking system as recited in claim 14, wherein: said storage counter is reset following each tracking operation to a prestored count corresponding to one-half of the gate count plus one-half of the estimated pulse width in accordance with the master clock pulse rate, and is operative to initiate counting at said master clock pulse rate upon receipt of said first pulse, through said prestored count, prior to accumulating a count until receipt of a subsequent pulse within said interval, and said transfer control means is operative to effect said jam transfer at a nominal time period equal to one quarter of the gate count at the master clock pulse rate following the gate end, whereby the next successive pulse following initiation of the tracking is predicted to occur with the center thereof in coincidence with the gate center.

Claim 19

Dependent Claim 153 words

A pulse train tracking system as recited in claim 15, the improvement further comprising: early gating means responsive to the output of said gate start decoder and said gate center decoder for gating master clock pulses to said early counter for the duration of a pulse occurrence within said early gate and said late gating means responsive to the output of said gate center decoder and gate end decoder for gating master clock pulses to said late counter for the duration of a pulse occurrence within said late gate, said early and late counters each include full count decoders providing error correction pulses to said first counter, and said first counter is controlled by said early and late gating means for counting in up or down directions, respectively, in response to error correction signals from said full decoders of said early and late counters, respectively, to correct errors in the predicted inter-pulse period.

Claim 20

Dependent Claim 249 words

In a pulse train tracking system as recited in claim 16 wherein said transfer control means further comprises: a phase counter having prestored therein a count substantially equal to one-half the count of said gate, gate means for selectively gating clock pulses to said phase counter for effecting counting thereby selectively at the master clock pulse rate and at twice the master clock pulse rate, said phase counter includes a zero count decoder responsive to count down of said phase counter to a count of zero for producing a transfer signal for effecting said jam transfer, and said gate means is responsive to the outputs of said gate start and gate center decoders to effect count down of said phase counter at the master clock pulse rate for the duration of a pulse occurrence within said early gate, to the outputs of said gate center and gate end decoders to effect count up of said phase counter at the master clock pulse rate for the duration of a pulse occurrence within said late gate and to the output of said gate end decoder to count down at twice the master clock pulse rate to a count of zero, a nominal time period after gate end, whereby said transfer signal is produced prior to or following said nominal time period by an amount equal to that by which the actual occurrence of the center of the pulse is prior to or later than the predicted occurrence thereof at gate center.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-08-18	1979-02-17	1979-08-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-08-18	1983-02-17	1983-08-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-08-18	1987-02-17	1987-08-19	$7700.00	Window Closed / Lapsed

Digital pulse train tracker

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