Patent US3852682A successfully refreshed from Google Patents.
US3852682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oscillation generators
Assignee: Marconi Instruments Ltd
•
Filing: 1973-06-22
•
Granted: 1974-12-03
•
Expires: 1993-06-22
Abstract
Abstract An oscillation generator in which a tunable oscillator is locked onto the sum of or difference between a reference frequency and an off-set frequency by comparing the oscillator output first with the reference and then comparing the result of the first comparison with the off-set frequency and in which the result of the first comparison is compared with the off-set frequency phase shifted by 90* the result of this last comparison being used to prevent the oscillator from locking onto the sum when the difference is required or vice-versa.
Inventors
- 👤 C Dawe
- 👤 J Middleton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:56
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/08; H03L7/10; H03L7/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
An oscillation generator including a voltage tunable oscillator; a first phase comparator connected to compare output from said oscillator with a reference frequency; a second phase comparator connected to compare output from said first comparator with an off-set frequency; a third phase comparator having two input channels one fed from the first phase comparator and the other fed with the off-set frequency, one of said input chaNnels having a phase shift of 90* relative to that of the other; a sweep or search oscillator; means for stopping said sweep oscillator sweeping if, and only if, the output of said third comparator is of a predetermined sign; means for combining output from said sweep oscillator with output derived from said second comparator; and means for utilising output from said combining means to control the tuning of said tunable oscillator.
Claim 2
Dependent Claim
138 words
An oscillation generator including a voltage tunable oscillator; a first phase comparator connected to compare output from said oscillator with a reference frequency; a second phase comparator connected to compare output from said first comparator with an off-set frequency; a third phase comparator having two input channels one fed from the first phase comparator and the other fed with the off-set frequency, one of said input chaNnels having a phase shift of 90* relative to that of the other; a sweep or search oscillator; means for stopping said sweep oscillator sweeping if, and only if, the output of said third comparator is of a predetermined sign; means for combining output from said sweep oscillator with output derived from said second comparator; and means for utilising output from said combining means to control the tuning of said tunable oscillator.
Claim 3
Dependent Claim
29 words
An oscillation generator according to claim 1 wherein a 90* phase shifter is included in the input channel through which the off-set frequency is supplied to the third comparator.
Claim 4
Dependent Claim
37 words
An oscillation generator according to claim 1 wherein a threshold circuit is interposed in a channel between the third comparator and the sweep oscillator to prevent the passage of signals of less than a predetermined threshold magnitude.
Claim 5
Dependent Claim
49 words
An oscillation generator according to claim 1 wherein a band pass filter is interposed in the path between the first and second comparators and low pass filters are interposed in the paths between the second comparator and the combining means and between the third comparator and the sweep oscillator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |