US3729674A
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US
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Digital nuclear gyroscopic instrumentation and digital phase locked loop therefor
Assignee: Kearfott Guidance and Navigation Corp
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Filing: 1970-12-02
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Granted: 1973-04-24
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Expires: 1990-12-02
Abstract
Abstract A pair of spin generators maintained parallel to each other, but in opposite directions thereto, are phase locked with respect to each other and an output is provided indicative of the inertial reference. Both spin generators include different sets of nuclei which resonate at two different distinct frequencies. A first crystal oscillator is initially phase locked with respect to one of the spin generators through the use of a dividing circuit, a multi-bit register, and a proportional field control for that spin generator. Similarly, the other spin generator is coupled to strobe a second multi-bit register which is coupled to the dividing circuit so as to provide a phase difference signal from the output of the second shift register, which phase difference signal is indicative of the difference in phase between the two spin generators. A second crystal oscillator oscillating at a frequency different from the first crystal oscillator is coupled to a second dividing circuit to a third multi-bit register which is coupled to the first spin generator. Additional pulses can be added to or removed from the path between the crystal oscillator and the second dividing circuit, so as to phase-lock the output of the second divider circuit with a second frequency output of the first spin generator. The second dividing circuit is coupled to the second spin generator by means of a fourth register. The outputs of the second and fourth registers are subtracted, one from the other through a difference circuit to control the south field proportional field control. The phase difference registers are also fed through a summing adder to provide the nuclear inertial output reference. A digital phase locked loop is provided for an input signal at a frequency fs. An n-stage counter is driven with a 2nxfs coherent source. The input signal and the output of the n-stage counter are coupled to a phase detector which samples the phase of the input signal. The detected signal is periodically integrated. The integrated signal is coupled to an analog to digital converter whose output controls a pulse advance or retard means which is serially coupled between the coherent source and the counter.
Inventors
- 👤 J Lowdenslager
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:49
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/26; H03L7/06; H03L7/08; H03L7/099; H03L7/0991; H03L7/0992; H03L7/0993
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
463 words
In combination, A. a north nuclear spin generator having a field control therefore, an upper output frequency, and a lower output frequency; B. a first strobing means coupled to the north spin generator for providing strobing signals at the upper frequency rate; C. a crystal oscillator; D. means for phase locking said crystal oscillator to said north spin generator upper frequency, 1. a frequency dividing circuit adapted to receive the output from said crystal oscillator and to provide a binary output therefrom at the same frequency as the north spin generator upper frequency, 2. a first error register, adapted to receive the binary outputsfrom said dividing circuit, said register adapted to receive a strobing signal from said first strobing means, and 3. means coupling the output of said error register to control proportionally the field for said north spin generator; E. a south spin generator having a field control therefore; F. a second error register coupled to receive the output from said dividing circuit; G. means coupled to said south spin generator for strobing the signal applied to said second error register, whereby said second error register provides an output therefrom indicative of the phase difference between said south spin generator and said north spin generator; H. a second crystal osciLlator adapted to oscillate at a frequency other than said first crystal oscillator; I. a second dividing circuit; J. means for coupling the output of said second oscillator to said second dividing circuit; K. a third error register; L. means coupled to said north spin generator for applying a strobe pulse to said third error register; so that synchronization of the output of said second dividing circuit with said strobing signals occurs; M. means for phase locking the output of said second dividing circuit to the strobe pulse applied to said third register and said coupling means so that the signal strobed into the third register has the identical scale as the first error register; 1. whereby said means for coupling, after each strobe pulse, shifts a new number therethrough, the output phase of said second dividing circuit being either advanced or retarded by the number stored in said third error register; N. a fourth error register; O. means for strobing the output of said second dividing circuit into said fourth error register, said means for strobing being controlled by said south spin generator; P. means for coupling the output from said second error register and the output from said fourth error register, combining them through a subtractor circuit, and coupling the output of said subtractor circuit to control the field of said south spin generator; and Q. an adder coupled to receive the outputs from said second and fourth error registers for providing an output therefrom indicative of the inertial output reference.
Claim 2
Dependent Claim
463 words
In combination, A. a north nuclear spin generator having a field control therefore, an upper output frequency, and a lower output frequency; B. a first strobing means coupled to the north spin generator for providing strobing signals at the upper frequency rate; C. a crystal oscillator; D. means for phase locking said crystal oscillator to said north spin generator upper frequency, 1. a frequency dividing circuit adapted to receive the output from said crystal oscillator and to provide a binary output therefrom at the same frequency as the north spin generator upper frequency, 2. a first error register, adapted to receive the binary outputsfrom said dividing circuit, said register adapted to receive a strobing signal from said first strobing means, and 3. means coupling the output of said error register to control proportionally the field for said north spin generator; E. a south spin generator having a field control therefore; F. a second error register coupled to receive the output from said dividing circuit; G. means coupled to said south spin generator for strobing the signal applied to said second error register, whereby said second error register provides an output therefrom indicative of the phase difference between said south spin generator and said north spin generator; H. a second crystal osciLlator adapted to oscillate at a frequency other than said first crystal oscillator; I. a second dividing circuit; J. means for coupling the output of said second oscillator to said second dividing circuit; K. a third error register; L. means coupled to said north spin generator for applying a strobe pulse to said third error register; so that synchronization of the output of said second dividing circuit with said strobing signals occurs; M. means for phase locking the output of said second dividing circuit to the strobe pulse applied to said third register and said coupling means so that the signal strobed into the third register has the identical scale as the first error register; 1. whereby said means for coupling, after each strobe pulse, shifts a new number therethrough, the output phase of said second dividing circuit being either advanced or retarded by the number stored in said third error register; N. a fourth error register; O. means for strobing the output of said second dividing circuit into said fourth error register, said means for strobing being controlled by said south spin generator; P. means for coupling the output from said second error register and the output from said fourth error register, combining them through a subtractor circuit, and coupling the output of said subtractor circuit to control the field of said south spin generator; and Q. an adder coupled to receive the outputs from said second and fourth error registers for providing an output therefrom indicative of the inertial output reference.
Claim 3
Dependent Claim
27 words
a first error register, adapted to receive the binary outputsfrom said dividing circuit, said register adapted to receive a strobing signal from said first strobing means, and
Claim 4
Dependent Claim
27 words
a first error register, adapted to receive the binary outputsfrom said dividing circuit, said register adapted to receive a strobing signal from said first strobing means, and
Claim 5
Dependent Claim
26 words
a frequency dividing circuit, coupled to said crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f1;
Claim 6
Dependent Claim
26 words
a frequency dividing circuit, coupled to said crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f1;
Claim 7
Dependent Claim
49 words
a register having an input terminal coupled to the output of said adding circuit, and an output terminal, coupled to said first input terminal of said adding circuit wherein said register continually updates a binary number contained therein by adding or subtracting thereto the output of said adding circuit;
Claim 8
Dependent Claim
49 words
a register having an input terminal coupled to the output of said adding circuit, and an output terminal, coupled to said first input terminal of said adding circuit wherein said register continually updates a binary number contained therein by adding or subtracting thereto the output of said adding circuit;
Claim 9
Dependent Claim
45 words
means coupled to said difference signal for controlling said second spin generator uniDirectional field varying means; and P. digital adding means coupled to the outputs of said third and fourth n stage registers for providing a summing signal therefrom indicative of an inertial output reference.
Claim 10
Dependent Claim
45 words
means coupled to said difference signal for controlling said second spin generator uniDirectional field varying means; and P. digital adding means coupled to the outputs of said third and fourth n stage registers for providing a summing signal therefrom indicative of an inertial output reference.
Claim 11
Dependent Claim
168 words
a proportional advance or retard means having an input coupled to said second crystal oscillator, an output coupled to said second dividing circuit, and control inputs coupled to the output of said second n stage register for adding or deleting pulses to second dividing circuit so that said second dividing circuit comes into synchronism with the nominal frequency f2 of the first spin generator; M. a third n stage flip flop register having input terminals coupled to the output of said first dividing circuit, and having a strobing terminal coupled to said second strobing means for gating signals from said first dividing circuit thereinto, and an output therefrom; N. a fourth n stage flip flop register having input terminals coupled to the output of said second dividing circuit, and having a strobing terminal coupled to said fourth strobing means for gating signals from the second dividing circuit thereinto, and an output therefrom; O. means for maintaining the second spin generator in synchronism with said first spin generator including
Claim 12
Dependent Claim
168 words
a proportional advance or retard means having an input coupled to said second crystal oscillator, an output coupled to said second dividing circuit, and control inputs coupled to the output of said second n stage register for adding or deleting pulses to second dividing circuit so that said second dividing circuit comes into synchronism with the nominal frequency f2 of the first spin generator; M. a third n stage flip flop register having input terminals coupled to the output of said first dividing circuit, and having a strobing terminal coupled to said second strobing means for gating signals from said first dividing circuit thereinto, and an output therefrom; N. a fourth n stage flip flop register having input terminals coupled to the output of said second dividing circuit, and having a strobing terminal coupled to said fourth strobing means for gating signals from the second dividing circuit thereinto, and an output therefrom; O. means for maintaining the second spin generator in synchronism with said first spin generator including
Claim 13
Dependent Claim
47 words
means coupled to the output of said n stage flip flop register for controlling said first spin generator unidirectional field varying means; L. means for maintaining the output of said second frequency dividing circuit in synchronism with the nominal frequency f2 from said first spin generator, including
Claim 14
Dependent Claim
47 words
means coupled to the output of said n stage flip flop register for controlling said first spin generator unidirectional field varying means; L. means for maintaining the output of said second frequency dividing circuit in synchronism with the nominal frequency f2 from said first spin generator, including
Claim 15
Dependent Claim
8 words
In combination, A. a first spin generator having
Claim 16
Dependent Claim
8 words
In combination, A. a first spin generator having
Claim 17
Dependent Claim
14 words
a container enclosing dissimilar subatomic particles, corresponding to those enclosed by said first container,
Claim 18
Dependent Claim
14 words
a container enclosing dissimilar subatomic particles, corresponding to those enclosed by said first container,
Claim 19
Dependent Claim
21 words
a first container, located in said field, enclosing two sets of dissimilar subatomic particles, each exhibiting magnetic resonance when properly excited;
Claim 20
Dependent Claim
21 words
a first container, located in said field, enclosing two sets of dissimilar subatomic particles, each exhibiting magnetic resonance when properly excited;
Claim 21
Dependent Claim
21 words
means for irradiating said first container with energy at the resonance frequency of at least one of said sets of particles,
Claim 22
Dependent Claim
21 words
means for irradiating said first container with energy at the resonance frequency of at least one of said sets of particles,
Claim 23
Dependent Claim
23 words
means for irradiating the second spin generator container with energy at the resonance frequency of at least one of said sets of particles,
Claim 24
Dependent Claim
23 words
means for irradiating the second spin generator container with energy at the resonance frequency of at least one of said sets of particles,
Claim 25
Dependent Claim
18 words
The combination as recited in claim 2 further comprising an averaging circuit coupled to said digital adding means.
Claim 26
Dependent Claim
60 words
a right shifting means having an input terminal coupled to said output terminal of said averaging circuit register and an output terminal for providing signals indicative of average data corresponding to the inertial output reference wherein said right shifting means has the capability of shifting the binary number on its input terminal to the right an integral number of digits;
Claim 27
Dependent Claim
60 words
a right shifting means having an input terminal coupled to said output terminal of said averaging circuit register and an output terminal for providing signals indicative of average data corresponding to the inertial output reference wherein said right shifting means has the capability of shifting the binary number on its input terminal to the right an integral number of digits;
Claim 28
Dependent Claim
36 words
a flip flop register having input terminals coupled to said frequency dividing circuit, a strobing terminal coupled to said strobing means for gating signals from said dividing circuit into the register, and an output therefrom; and
Claim 29
Dependent Claim
36 words
a flip flop register having input terminals coupled to said frequency dividing circuit, a strobing terminal coupled to said strobing means for gating signals from said dividing circuit into the register, and an output therefrom; and
Claim 30
Dependent Claim
203 words
means coupling the output of said error register to control proportionally the field for said north spin generator; E. a south spin generator having a field control therefore; F. a second error register coupled to receive the output from said dividing circuit; G. means coupled to said south spin generator for strobing the signal applied to said second error register, whereby said second error register provides an output therefrom indicative of the phase difference between said south spin generator and said north spin generator; H. a second crystal osciLlator adapted to oscillate at a frequency other than said first crystal oscillator; I. a second dividing circuit; J. means for coupling the output of said second oscillator to said second dividing circuit; K. a third error register; L. means coupled to said north spin generator for applying a strobe pulse to said third error register; so that synchronization of the output of said second dividing circuit with said strobing signals occurs; M. means for phase locking the output of said second dividing circuit to the strobe pulse applied to said third register and said coupling means so that the signal strobed into the third register has the identical scale as the first error register;
Claim 31
Dependent Claim
203 words
means coupling the output of said error register to control proportionally the field for said north spin generator; E. a south spin generator having a field control therefore; F. a second error register coupled to receive the output from said dividing circuit; G. means coupled to said south spin generator for strobing the signal applied to said second error register, whereby said second error register provides an output therefrom indicative of the phase difference between said south spin generator and said north spin generator; H. a second crystal osciLlator adapted to oscillate at a frequency other than said first crystal oscillator; I. a second dividing circuit; J. means for coupling the output of said second oscillator to said second dividing circuit; K. a third error register; L. means coupled to said north spin generator for applying a strobe pulse to said third error register; so that synchronization of the output of said second dividing circuit with said strobing signals occurs; M. means for phase locking the output of said second dividing circuit to the strobe pulse applied to said third register and said coupling means so that the signal strobed into the third register has the identical scale as the first error register;
Claim 32
Dependent Claim
45 words
means for producing an alternating magnetic field, associated with the second spin generator unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about the second spin generator fixed axis,
Claim 33
Dependent Claim
45 words
means for producing an alternating magnetic field, associated with the second spin generator unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about the second spin generator fixed axis,
Claim 34
Dependent Claim
19 words
means coupled to the output of said flip flop register for controlling said spin generator undirectional field varying means.
Claim 35
Dependent Claim
19 words
means coupled to the output of said flip flop register for controlling said spin generator undirectional field varying means.
Claim 36
Dependent Claim
35 words
a subtracting circuit having a first input terminal coupled to the output terminal of said right shift means, a second input terminal coupled to the input of said averaging circuit, and an output terminal therefrom;
Claim 37
Dependent Claim
35 words
a subtracting circuit having a first input terminal coupled to the output terminal of said right shift means, a second input terminal coupled to the input of said averaging circuit, and an output terminal therefrom;
Claim 38
Dependent Claim
12 words
The combination as recited in claim 3 wherein said averaging circuit includes
Claim 39
Dependent Claim
39 words
means for producing an alternating magnetic field, associated with said first unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about said axis,
Claim 40
Dependent Claim
39 words
means for producing an alternating magnetic field, associated with said first unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about said axis,
Claim 41
Dependent Claim
7 words
means for varying said unidirectional field, and
Claim 42
Dependent Claim
7 words
means for varying said unidirectional field, and
Claim 43
Dependent Claim
10 words
means for varying the second spin generator unidirectional field, and
Claim 44
Dependent Claim
10 words
means for varying the second spin generator unidirectional field, and
Claim 45
Dependent Claim
33 words
means for coupling the output terminal of said subtracting circuit to the second input terminal of said adding circuit, and for providing signals indicative of differential data of the inertial output reference; and
Claim 46
Dependent Claim
33 words
means for coupling the output terminal of said subtracting circuit to the second input terminal of said adding circuit, and for providing signals indicative of differential data of the inertial output reference; and
Claim 47
Dependent Claim
152 words
In combination with a crystal oscillator having a resonance frequency 2n f1; and a spin generator having a unidirectional magnetic field, aligned along a fixed axis, a container enclosing two sets of dissimilar subatomic particles, each exhibiting magnetic resonance when properly excited, located in said field, means for irradiating said container with energy at the resonance frequency of at least one of said sets of particles, means for producing an alternating magnetic field, associated with said unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about said axis, means for varying said unidirectional field, and means for detecting the precessional frequency of said particles, the precessional frequency of one set of particles having a nominal frequency f1; means for phase locking the nominal frequency f1, from the spin generator in synchronism with said crystal oscillator comprising
Claim 48
Dependent Claim
152 words
In combination with a crystal oscillator having a resonance frequency 2n f1; and a spin generator having a unidirectional magnetic field, aligned along a fixed axis, a container enclosing two sets of dissimilar subatomic particles, each exhibiting magnetic resonance when properly excited, located in said field, means for irradiating said container with energy at the resonance frequency of at least one of said sets of particles, means for producing an alternating magnetic field, associated with said unidirectional field, having a frequency equal to the Larmor frequency of each set of particles to cause forced precession of magnetic moments of said particles about said axis, means for varying said unidirectional field, and means for detecting the precessional frequency of said particles, the precessional frequency of one set of particles having a nominal frequency f1; means for phase locking the nominal frequency f1, from the spin generator in synchronism with said crystal oscillator comprising
Claim 49
Dependent Claim
19 words
means for coupling the output terminal of said right shifting means to the second terminal of said substracting circuit.
Claim 50
Dependent Claim
19 words
means for coupling the output terminal of said right shifting means to the second terminal of said substracting circuit.
Claim 51
Dependent Claim
312 words
means for detecting the precessional frequencies of said particles, the precessional frequency of one set of particles having said nominal frequency f1, the precessional frequency of the other set of particles having said nominal frequency f2; C. a first strobing means coupled to said detecting means of said first spin generator, including a filter at the frequency f1, And pulse shaping means, for providing strobing pulses at said nominal frequency f1 in synchronism with said first spin generator; D. a second strobing means coupled to said detecting means of said second spin generator, including a filter at the frequency f1, and pulse shaping means, for providing strobing pulses at said nominal frequency f1 in synchronism with said second spin generator; E. a third strobing means coupled to said detecting means of said first spin generator, including a filter at the frequency f2, and pulse shaping means, for providing strobing pulses at said nominal frequency f2 in synchronism with said first spin generator; F. a fourth strobing means coupled to said detecting means of said second spin generator, including a filter at the frequency f2, and pulse shaping means, for providing strobing pulses at said nominal frequency f2 in synchronism with said second spin generator; G. a first crystal oscillator having a resonance frequency 2n f2, wherein n is a positive integer; H. a second crystal oscillator having a resonance frequency 2n f2; I. a first frequency dividng circuit, coupled to said first crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f1; J. a second frequency dividing circuit, coupled to said second crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f2; K. means for phase locking the nominal frequency f1 from the first spin generator in synchronism with said first crystal oscillator, including
Claim 52
Dependent Claim
312 words
means for detecting the precessional frequencies of said particles, the precessional frequency of one set of particles having said nominal frequency f1, the precessional frequency of the other set of particles having said nominal frequency f2; C. a first strobing means coupled to said detecting means of said first spin generator, including a filter at the frequency f1, And pulse shaping means, for providing strobing pulses at said nominal frequency f1 in synchronism with said first spin generator; D. a second strobing means coupled to said detecting means of said second spin generator, including a filter at the frequency f1, and pulse shaping means, for providing strobing pulses at said nominal frequency f1 in synchronism with said second spin generator; E. a third strobing means coupled to said detecting means of said first spin generator, including a filter at the frequency f2, and pulse shaping means, for providing strobing pulses at said nominal frequency f2 in synchronism with said first spin generator; F. a fourth strobing means coupled to said detecting means of said second spin generator, including a filter at the frequency f2, and pulse shaping means, for providing strobing pulses at said nominal frequency f2 in synchronism with said second spin generator; G. a first crystal oscillator having a resonance frequency 2n f2, wherein n is a positive integer; H. a second crystal oscillator having a resonance frequency 2n f2; I. a first frequency dividng circuit, coupled to said first crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f1; J. a second frequency dividing circuit, coupled to said second crystal oscillator, and adapted to provide a binary output along n output lines therefrom at a cyclic rate f2; K. means for phase locking the nominal frequency f1 from the first spin generator in synchronism with said first crystal oscillator, including
Claim 53
Dependent Claim
42 words
means for detecting the precessional frequencies of said particles, the precessional frequency of one set of particles having a nominal frequency f1, the precessional frequency of the other set of particles having a nominal frequency f2; B. a second spin generator having
Claim 54
Dependent Claim
42 words
means for detecting the precessional frequencies of said particles, the precessional frequency of one set of particles having a nominal frequency f1, the precessional frequency of the other set of particles having a nominal frequency f2; B. a second spin generator having
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |