US3845393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Communication receiver with tuning circuits that track the l.o.
Assignee: US Philips Corp
•
Filing: 1973-03-14
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Granted: 1974-10-29
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Expires: 1993-03-14
Abstract
Abstract A receiver has a synthesized L.O. A code converter is coupled to it and causes the R.F. tuned circuits to track the frequency of the L.O.
Inventors
- 👤 J Basset
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:25
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/02; H03J3/16; H03J3/18; H03J3/185; H03J5/00; H03J5/02; H03J5/0209; H03J5/0245; H03J5/0272; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/183; H03L7/187; H03L7/189
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
A circuit comprising a first tuned circuit having a voltage variable reactance element having a first voltage versus frequency characteristic; a frequency synthesizer including a voltage controlled oscillator having a second control voltage verses frequency characteristic differing from said first characteristic, and a first control loop having means for generating a digital signal representative of a selected frequency coupled to said oscillator; and means for tracking the resonant frequency of said tuning tuned circuit with the oscillation frequency of said voltage controlled oscillator, said tracking means comprising means coupled to said digital generating means for code converting said digital signal into another digital signal compatible with said first characteristic, and a digital to analogue converter coupled to said code converter and said element.
Claim 2
Dependent Claim
123 words
A circuit comprising a first tuned circuit having a voltage variable reactance element having a first voltage versus frequency characteristic; a frequency synthesizer including a voltage controlled oscillator having a second control voltage verses frequency characteristic differing from said first characteristic, and a first control loop having means for generating a digital signal representative of a selected frequency coupled to said oscillator; and means for tracking the resonant frequency of said tuning tuned circuit with the oscillation frequency of said voltage controlled oscillator, said tracking means comprising means coupled to said digital generating means for code converting said digital signal into another digital signal compatible with said first characteristic, and a digital to analogue converter coupled to said code converter and said element.
Claim 3
Dependent Claim
94 words
A circuit as claimed in claim 1, wherein said first control loop generates a course frequency control voltage and further comprising a second frequency control loop for applying a fine frequency control voltage to said oscillator, means cOupled to second loop for supplying a digital signal which is representative of the fine frequency control voltage applied to the oscillator, means coupled to said loops and said code converter for adding the signal which is representative of the fine frequency control voltage to the digital signal which is representative of the coarse frequency control voltage.
Claim 4
Dependent Claim
30 words
A circuit as claimed in Claim 1, wherein said generating means includes an up-down counter, and said first loop includes a frequency discriminator having an output coupled to said counter.
Claim 5
Dependent Claim
15 words
A circuit as claimed in claim 1, wherein the code converter comprises a read-only memory.
Claim 6
Dependent Claim
84 words
A circuit as claimed in claim 1 wherein said first tuned circuit is tuned to a first subrange of said oscillator and said generating means comprises means coupled to said code converter for applying a digital signal representative of a subrange, and further comprising a second tuned circuit tuned to a second subrange, said code converter having output means for providing a subrange indication signal, and switching means coupled to said tuned circuits and having a control input means coupled to said output means.
Claim 7
Independent Claim
105 words
A method for tracking the resonant frequency of a tuned circuit having a voltage variable reactance element having a first voltage versus frequency characteristic, a voltage controlled oscillator having a second voltage versus frequency characteristic differing from said first characteristic, said method comprising the steps of generating a first digital signal from said VCO signal, controlling the VCO with said first digital signal; code converting said first digital signal used to control the frequency of said oscillator into a second digital signal compatible with said second characteristic, converting said second digital signal into an analogue signal, and applying said analogue signal to said reactance element.
Claim 8
Independent Claim
105 words
A method for tracking the resonant frequency of a tuned circuit having a voltage variable reactance element having a first voltage versus frequency characteristic, a voltage controlled oscillator having a second voltage versus frequency characteristic differing from said first characteristic, said method comprising the steps of generating a first digital signal from said VCO signal, controlling the VCO with said first digital signal; code converting said first digital signal used to control the frequency of said oscillator into a second digital signal compatible with said second characteristic, converting said second digital signal into an analogue signal, and applying said analogue signal to said reactance element.
Claim 9
Dependent Claim
35 words
A method as claimed in claim 6 further comprising controlling said oscillator frequency using a third digital signal to effect fine frequency control, and adding said first and third signals before said code converting step.
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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) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |