US3568062A
Expired / Lapsed
US
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Discrete compandor utilizing hysteresis
Assignee: AT&T Inc
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Filing: 1968-04-29
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Granted: 1971-03-02
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Expires: 1988-04-29
Abstract
Abstract In a delta modulation transmission system employing discrete companding utilizing a discretely variable step size, a hysteresis circuit is added to minimize step size transitions by altering the traversed predetermined level in the pulse code modulation encoder which determines the discrete step size used for the delta modulator.
Inventors
- 👤 Stephen J Brolin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:11
CPC Classifications
H; H03; H03M; H03M3/00; H03M3/02; H03M3/022; H03M3/024
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
159 words
In a delta modulation transmission system with companding for transmission of a message signal including a delta modulator, said delta modulator comprising: means to apply the message signal to one input of a two-input comparator; means to produce a pulse having one polarity when the output of said comparator is positive and a pulse of the opposite polarity when the output of said comparator is negative; means to integrate said pulse and apply it to the second input of said two-input comparator; means to discretely vary the magnitude of said pulse, said last means comprising: a level sensor for sensing the level of sAid message signal; means to provide a plurality of predetermined comparison levels; means to produce a binary code responsive to the predetermined comparison level exceeded by said message signal; means responsive to said binary code to control the magnitude of said pulse; and means responsive to said binary code to vary said exceeded predetermined comparison level.
Claim 2
Dependent Claim
159 words
In a delta modulation transmission system with companding for transmission of a message signal including a delta modulator, said delta modulator comprising: means to apply the message signal to one input of a two-input comparator; means to produce a pulse having one polarity when the output of said comparator is positive and a pulse of the opposite polarity when the output of said comparator is negative; means to integrate said pulse and apply it to the second input of said two-input comparator; means to discretely vary the magnitude of said pulse, said last means comprising: a level sensor for sensing the level of sAid message signal; means to provide a plurality of predetermined comparison levels; means to produce a binary code responsive to the predetermined comparison level exceeded by said message signal; means responsive to said binary code to control the magnitude of said pulse; and means responsive to said binary code to vary said exceeded predetermined comparison level.
Claim 3
Dependent Claim
19 words
Apparatus as set forth in claim 1 wherein said exceeded predetermined comparison level is lowered by a fixed amount.
Claim 4
Dependent Claim
85 words
Apparatus as set forth in claim 2 wherein said means to vary said exceeded predetermined comparison level comprises; a plurality of AND gates each responsive to a different one of said binary codes; a plurality of resistors, with one resistor of said plurality connected to a respective one of said plurality of AND gates; and means responsive to said produced binary code to supply a bias current to said level sensor through said resistor associated with said AND gate enabled by said produced binary code.
Claim 5
Dependent Claim
20 words
Apparatus as set forth in claim 3 wherein the resistance of each resistor in said plurality of resistors is different.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |