US3760407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
P c m coders
Assignee: BAE Systems Electronics Ltd
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Filing: 1971-12-10
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Granted: 1973-09-18
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Expires: 1991-12-10
Abstract
Abstract To achieve a segmented-law analogue to digital signal conversion, a capacitor is charged by a constant current which changes as the states of the three most significant digits of a binary counter, counting pulses supplied by an oscillator, change. Counting ceases and the count is read out when the capacitor voltage reaches the sampled analogue signal voltage. The constant current is derived from a constant current generator and either three current dividers or three or more further constant current generators which are switched in to or out of circuit as the count changes.
Inventors
- 👤 J Terry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:57
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
195 words
An analogue to digital coder including an oscillator; a digital counter wHich is fed with output from said oscillator; a constant current generator; a capacitor which is recurrently charged by a charging current derived from the said constant current generator; control means dependent on the contents of the digital counter for controlling said charging current; comparison means for comparing the amplitude of an analogue signal with the potential existing on the said capacitor at a given instant in time; and gating means for stopping the said counter when the potential stored on the capacitor is substantially equal to the amplitude of said sampled analogue signal; a gate interposed between the oscillator and the digital counter which is closed or opened by a comparator in dependence on whether the sampled analogue signal is equal to or greater than the instantaneous potential stored on the capacitor respectively, a plurality of constant current generators whose output current may be selectively combined in dependence on the contents of the said digital counter; and a frequency divider positioned between the said oscillator and the digital counter which is also controlled in dependence on the contents of the said digital counter.
Claim 2
Dependent Claim
195 words
An analogue to digital coder including an oscillator; a digital counter wHich is fed with output from said oscillator; a constant current generator; a capacitor which is recurrently charged by a charging current derived from the said constant current generator; control means dependent on the contents of the digital counter for controlling said charging current; comparison means for comparing the amplitude of an analogue signal with the potential existing on the said capacitor at a given instant in time; and gating means for stopping the said counter when the potential stored on the capacitor is substantially equal to the amplitude of said sampled analogue signal; a gate interposed between the oscillator and the digital counter which is closed or opened by a comparator in dependence on whether the sampled analogue signal is equal to or greater than the instantaneous potential stored on the capacitor respectively, a plurality of constant current generators whose output current may be selectively combined in dependence on the contents of the said digital counter; and a frequency divider positioned between the said oscillator and the digital counter which is also controlled in dependence on the contents of the said digital counter.
Claim 3
Dependent Claim
66 words
A coder as claimed in claim 1 wherein there are provided four constant current generators having pre-determined output currents, and which are controlled in dependence on the contents of the two most significant bits in the digital counter, and the said divider is adapted to divide the frequency by a factor of two and is controlled by the third most significant bit in the digital counter.
Claim 4
Dependent Claim
24 words
A coder as claimed in claim 2 wherein the four constant current generators provide currents having relative magnitudes of unity, three, 12 and 48.
Claim 5
Dependent Claim
45 words
A coder as claimed in claim 3 wherein the frequency divider and the four current generators are controlled by the binary counter to provide as an output from the binary counter a digital code which is related to the analogue signal by a geometrical segmented-law.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |