US3909824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-linear analogue-digital converter for compression coding
Assignee: EUROPEENNE DE TELETRANSMISSION C E T T Cie
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Filing: 1974-07-23
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Granted: 1975-09-30
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Expires: 1994-07-23
Abstract
Abstract Two integrators are charged proportionally to the sampled analogue signal, but with different proportionality coefficients, the first integrator being used for coding the lower (in absolute value) amplitudes, and the second one the higher amplitudes. They are discharged according to non-linear laws so that the discharge time of the first one be proportional to the compressed amplitude for lower sampled amplitudes and that of the second one to the compressed amplitude for higher sampled amplitudes, the proportionality coefficient being this time the same for both integrators. According to whether the absolute value of the charge of the second integrator has reached or not a threshold value, clock pulses are fed to a counter for the duration of the discharge time of the second or of the first integrator.
Inventors
- 👤 Sylvain Fontanes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:24
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
475 words
An analogue-digital converter for coding an analogue signal and simultaneously compressing it according to a compression characteristic A'' f(A), where A is the amplitude to be coded and compressed, and A'' the value of the corresponding coded signal, said characteristic being formed by a succession of straight line segments having q different slopes, q being an integer greater than p, the latter being an integer greater than one, and the segments having the p steepest slopes corresponding to those amplitudes A which are, in absolute value, smaller than a threshold value, said analogue-digital converter comprising: a first arrangement, including an integrator having an output, for, during first recurrent predetermined time intervals, sampling said analogue signal and charging said integrator proportionally to the amplitude of the sampled analogue signal, at least if the absolute value of this amplitude is not higher than said threshold value, with a first proportionality coefficient; means, for, in the course of further time intervals respectively following said first time intervals, non-linearly discharging said integrator as a function of time through modifying the discharge time constant of said integrator according to a predetermined programme so that the discharge time be proportional to the value A'' corresponding to the amplitude of the sampled analogue signal, at least if the absolute value of this amplitude is not higher than said threshold value, with a second proportionality coefficient; a second arrangement including a further integrator having an output, means for, during said first time intervals, sampling said analogue signal and charging said further integrator proportionally to the amplitude of the sampled analogue signal with a third proportionality coefficient smaller than said first proportionality coefficient; means, for in the course of said further time intervals, non-linearly discharging said further integrator as a function of time, through modifying the discharge time constant of said further integrator according to a further predetermined programme so that the discharge time be proportional to the value A'' corresponding to the amplitude of the sampled analogue signal at least if the absolute value of this amplitude is higher than said threshold value, with a proportionality coefficient equal to said second proportionality coefficient; pulse counting means, including a pulse generator for delivering pulses at a fixed frequency and a counter; control means, coupled to the output of one of said integrators, for causing the feeding of said pulses to said counter during the discharge time of said further integrator or of said integrator of said first arrangement according to whether the absolute value of the charge of that integrator to the output of which said control means are coupled has or has not reached, at the end of the time interval during which said two integrators were charged, a limiting valUe indicating that the absolute value of the amplitude of the corresponding sampled analogue signal was at least equal to said threshold value.
Claim 2
Dependent Claim
475 words
An analogue-digital converter for coding an analogue signal and simultaneously compressing it according to a compression characteristic A'' f(A), where A is the amplitude to be coded and compressed, and A'' the value of the corresponding coded signal, said characteristic being formed by a succession of straight line segments having q different slopes, q being an integer greater than p, the latter being an integer greater than one, and the segments having the p steepest slopes corresponding to those amplitudes A which are, in absolute value, smaller than a threshold value, said analogue-digital converter comprising: a first arrangement, including an integrator having an output, for, during first recurrent predetermined time intervals, sampling said analogue signal and charging said integrator proportionally to the amplitude of the sampled analogue signal, at least if the absolute value of this amplitude is not higher than said threshold value, with a first proportionality coefficient; means, for, in the course of further time intervals respectively following said first time intervals, non-linearly discharging said integrator as a function of time through modifying the discharge time constant of said integrator according to a predetermined programme so that the discharge time be proportional to the value A'' corresponding to the amplitude of the sampled analogue signal, at least if the absolute value of this amplitude is not higher than said threshold value, with a second proportionality coefficient; a second arrangement including a further integrator having an output, means for, during said first time intervals, sampling said analogue signal and charging said further integrator proportionally to the amplitude of the sampled analogue signal with a third proportionality coefficient smaller than said first proportionality coefficient; means, for in the course of said further time intervals, non-linearly discharging said further integrator as a function of time, through modifying the discharge time constant of said further integrator according to a further predetermined programme so that the discharge time be proportional to the value A'' corresponding to the amplitude of the sampled analogue signal at least if the absolute value of this amplitude is higher than said threshold value, with a proportionality coefficient equal to said second proportionality coefficient; pulse counting means, including a pulse generator for delivering pulses at a fixed frequency and a counter; control means, coupled to the output of one of said integrators, for causing the feeding of said pulses to said counter during the discharge time of said further integrator or of said integrator of said first arrangement according to whether the absolute value of the charge of that integrator to the output of which said control means are coupled has or has not reached, at the end of the time interval during which said two integrators were charged, a limiting valUe indicating that the absolute value of the amplitude of the corresponding sampled analogue signal was at least equal to said threshold value.
Claim 3
Dependent Claim
38 words
An analogue digital converter as claimed in claim 1, wherein said control means are coupled to the output of said further integrator, and wherein said limiting value is proportional, with said third proportionality coefficient, to said threshold value.
Claim 4
Dependent Claim
55 words
An analogue digital converter as claimed in claim 1, wherein a single time constant is used in said further programme for the initial part of the discharge corresponding to the discharge of the charge taken by said further integrator for an amplitude of the sampled analogue signal equal, in absolute value, to said threshold value.
Claim 5
Dependent Claim
97 words
An analogue-digital converter as claimed in claim 1 for coding an analogue signal whose amplitude is alternately positive and negative, further comprising additional means, coupled to the output of one of said integrators, for determining the sign of the charge thereof; and means, coupled to said additional means for adding a sign signal to the output signal of said counter; said additional means being coupled to said means for discharging said integrator of said first arrangement and to said means for discharging said further integrator, for determining the sign of the discharge voltage applied to said integrators.
References Cited (Backward Citations)
US3749894A
Cited
US3842416A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |