US3675146A
Expired / Lapsed
US
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Digital variable frequency oscillator
Assignee: Individual
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Filing: 1971-03-08
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Granted: 1972-07-04
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Expires: 1991-03-08
Abstract
Abstract A plural oscillator system with all the characteristics of an analog or variable frequency oscillator, but with the added capability of locking digitally to any frequency within its range. The system has two modes of operation, unlocked and locked. In the unlocked mode, the system employs a variable frequency oscillator together with a reference oscillator and counter to produce the system output and to log the period of the variable frequency oscillator into a memory. In the locked mode, the contents of the memory are held constant, and the variable frequency oscillator no longer drives the system output. Instead, the reference oscillator and counter are used in conjunction with a digital comparator to produce the system output with a frequency determined by the contents of the memory. Thus, the system in the locked mode operates as a digital oscillator at the frequency that the variable frequency oscillator operated before the mode change.
Inventors
- 👤 J Michael Langham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:08
CPC Classifications
H; H03; H03B; H03B21/00; H03B21/01; H03B21/02; H03B21/025
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
60 words
A plural oscillator apparatus comprising an analog oscillator operating at a selected frequency, a digital oscillator, and means connecting said analog and digital oscillators to operate the analog oscillator as a master determining the selected frequency and to operate the digital oscillator as a slave to produce an output frequency as a function of the period of said selected frequency.
Claim 2
Dependent Claim
60 words
A plural oscillator apparatus comprising an analog oscillator operating at a selected frequency, a digital oscillator, and means connecting said analog and digital oscillators to operate the analog oscillator as a master determining the selected frequency and to operate the digital oscillator as a slave to produce an output frequency as a function of the period of said selected frequency.
Claim 3
Dependent Claim
110 words
A plural oscillator apparatus as defined in claim 1 and wherein said digital oscillator includes a fixed frequency reference oscillator and a digital counter responsive to the reference oscillator and said means includes a memory and a mode selector buffer for selectively connecting said analog and digital oscillators in first and second modes of operation, said first mode of operation being characterized in that a count representative of the period of the frequency determined by the analog oscillator is repeatedly logged into the memory, and said second mode of operation being characterized in that the digital oscillator produces system output at a frequency that is a function of said period.
Claim 4
Dependent Claim
54 words
A plural oscillator apparatus as defined in claim 2 wherein in said first mode of operation said mode selector buffer applies successive output pulses from the analog oscillator both to said counter and to said memory to repeatedly store an updated count in the memory representative of the instantaneous frequency of the analog oscillator.
Claim 5
Dependent Claim
61 words
A plural oscillator apparatus as defined in claim 3 wherein, in said second mode of operation, said mode selector buffer connects a comparator to respond to said memory and to said counter to provide an output pulse to a system output terminal and to reset the counter each time the count in the counter reaches the count stored in the memory.
Claim 6
Dependent Claim
89 words
A plural oscillator apparatus as defined in claim 2 wherein, in said first mode of operation, said mode selector buffer applies successive output pulses from the analog oscillator both to said counter and to said memory to cause each such pulse to load the instantaneous count from the counter into the memory as a representation of the period of the instantaneous frequency of the analog oscillator and to reset the counter, said mode selector buffer also applying successive output pulses from the analog oscillator to a system output terminal.
Claim 7
Dependent Claim
47 words
A plural oscillator apparatus as defined in claim 4 wherein said mode selector buffer includes delay means for effecting transition from said first mode to said second mode concurrently with the output pulse from said analog oscillator to initiate said second mode when the counter is reset.
Claim 8
Dependent Claim
83 words
A plural oscillator apparatus as defined in claim 1 and wherein said means includes a memory and a mode selector buffer operable in a first mode to connect said analog oscillator to produce system output and to repeatedly update the memory to store a count representative of the period of the instantaneous frequency of said analog oscillator and operable in a second mode to connect said digital oscillator to produce system output as a function of the period last stored in the memory.
Claim 9
Dependent Claim
117 words
Plural oscillator apparatus as defined in claim 1 wherein said digital oscillator includes a reference oscillator, a counter and a comparator and said means includes a memory and a mode selector buffer operable in a first mode to connect said analog oscillator to produce system output and to actuate said memory and reset said counter for repeatedly updating the memory to store a count representative of the period of the instantaneous frequency of the analog oscillator and operable in a second mode to connect the comparator to respond to said memory and to said counter to produce system output and to reset said counter when the count in the counter reaches the count stored in the memory.
Claim 10
Dependent Claim
32 words
A plural oscillator apparatus as defined in claim 8 wherein said mode selector means includes means for synchronizing transition from said first mode to said second mode with reset of said counter.
Claim 11
Dependent Claim
98 words
A plural oscillator apparatus as defined in claim 1 and wherein said means includes a memory and a mode selector buffer operable in a first mode to connect said analog oscillator to repeatedly update the memory to store a count representative of the period of the instantaneous frequency of said analog oscillator and to connect the digital oscillator to the memory to produce system output as a function of the period count in said memory and operable in a second mode to retain the count last stored in the memory while continuing the operation of the digital oscillator.
Claim 12
Dependent Claim
26 words
A plural oscillator apparatus as defined in claim 1 and including a second digital oscillator connected to operate in parallel with the first named digital oscillator.
Claim 13
Dependent Claim
143 words
A plural oscillator apparatus as defined in claim 1 wherein said digital oscillator includes a first reference oscillator, a first counter and a comparator and said means includes a memory, a second reference oscillator, a second counter and a mode selector buffer operable in a first mode to connect said analog oscillator to actuate said memory and reset said second counter for repeatedly updating said memory to store a count representative of the period of the instantaneous frequency of the analog oscillator and to connect said comparator to respond to said memory and to said first counter to produce system output and to reset said first counter when the count in said first counter reaches the count stored in the memory and operable in a second mode to retain the count last stored in the memory while continuing the operation of the comparator.
Claim 14
Dependent Claim
26 words
A plural oscillator apparatus as defined in claim 12 and including a second digital oscillator connected to operate in parallel with the first named digital oscillator.
Claim 15
Independent Claim
94 words
A method of providing oscillation at a selected frequency comprising generating a train of pulses at a fixed frequency, analog generating a train of pulses at a frequency substantially less than said fixed frequency, applying successive analog generated pulses to store a count of the fixed frequency pulses in accordance with the period defined by said successive analog generated pulses, generating a train of pulses at a fixed frequency, counting the last-named fixed frequency pulses, and producing an output pulse each time the count of the last-named fixed frequency pulses equals the stored count.
Claim 16
Independent Claim
94 words
A method of providing oscillation at a selected frequency comprising generating a train of pulses at a fixed frequency, analog generating a train of pulses at a frequency substantially less than said fixed frequency, applying successive analog generated pulses to store a count of the fixed frequency pulses in accordance with the period defined by said successive analog generated pulses, generating a train of pulses at a fixed frequency, counting the last-named fixed frequency pulses, and producing an output pulse each time the count of the last-named fixed frequency pulses equals the stored count.
References Cited (Backward Citations)
US3568083A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |