US3596267A
Expired / Lapsed
US
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Digital code converter for converting a delta modulation code to a different permutation code
Assignee: AT&T Inc
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Filing: 1969-01-28
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Granted: 1971-07-27
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Expires: 1989-01-28
Abstract
Abstract A delta modulation to other permutation code signal converter comprises a shift register and up-down counter in series. The counter produces a permutation code output indicative of the running history of the delta modulation input, while the shift register, through weighted coefficient multipliers, produces correction signals to reduce the noise content of the counter output.
Inventors
- 👤 David J Goodman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:22
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/3002; H03M7/3048
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
181 words
In a digital message transmission system having a transmitting terminal and a receiving terminal, a delta modulator at the transmitting terminal for sampling and encoding the message to be transmitted in a binary pulse train, a converter for converting the binary pulse train directly to a permutation code signal having a plurality of digit combinations different from said delta modulation signal, said converter comprising a first means for shifting the permutation code signal in one direction in response to one condition of the delta modulation signal and in the opposite direction in response to another condition of the delta modulation signal, and second means for modifying the permutation code signal generated by said first means to conform to the system noise requirements by sampling the delta modulation pulse train in advance of its introduction into said first means and generating correcting pulses in the said permutation code, means for combining the outputs of said first and second means to produce a modified signal, and means for sampling and transmitting to said receiving terminal the modified signal at the permutation code rate.
Claim 2
Dependent Claim
181 words
In a digital message transmission system having a transmitting terminal and a receiving terminal, a delta modulator at the transmitting terminal for sampling and encoding the message to be transmitted in a binary pulse train, a converter for converting the binary pulse train directly to a permutation code signal having a plurality of digit combinations different from said delta modulation signal, said converter comprising a first means for shifting the permutation code signal in one direction in response to one condition of the delta modulation signal and in the opposite direction in response to another condition of the delta modulation signal, and second means for modifying the permutation code signal generated by said first means to conform to the system noise requirements by sampling the delta modulation pulse train in advance of its introduction into said first means and generating correcting pulses in the said permutation code, means for combining the outputs of said first and second means to produce a modified signal, and means for sampling and transmitting to said receiving terminal the modified signal at the permutation code rate.
Claim 3
Dependent Claim
67 words
In a digital transmission system having a transmitting and a receiving terminal, the combination as claimed in claim 1 wherein the delta modulation sampling rate and the permutation code rate are given by R 1/2W Tau where 1/ Tau is the delta modulation sampling rate, 1/2W is the permutation code sampling rate, R is an integer, and W is the highest frequency of the message being encoded.
Claim 4
Dependent Claim
64 words
In a digital transmission system having a transmitting and a receiving terminal, the combination as claimed in claim 1 wherein said first converter means comprises means for producing an output based upon the history of the delta modulation signal and the second converter means comprises means for producing an output that is an interpolation of a plurality of pulses of the delta modulation signal.
Claim 5
Dependent Claim
107 words
A converter for converting a delta modulation signal to a different permutation code signal comprising a shift register and an up-down counter in series, said shift register having a plurality of stages, each stage being connected to a weighted coefficient digital multiplier, the coefficient value of each multiplier being determined in part by the particular stage of the shift register to which it is connected, the outputs of said up-down counter and said digital multipliers being coded in the particular permutation code desired, and means for combining the outputs of the digital multipliers and the up-down counter to produce an output signal in the aforementioned permutation code.
Claim 6
Dependent Claim
107 words
A converter for converting a delta modulation signal to a different permutation code signal comprising a shift register and an up-down counter in series, said shift register having a plurality of stages, each stage being connected to a weighted coefficient digital multiplier, the coefficient value of each multiplier being determined in part by the particular stage of the shift register to which it is connected, the outputs of said up-down counter and said digital multipliers being coded in the particular permutation code desired, and means for combining the outputs of the digital multipliers and the up-down counter to produce an output signal in the aforementioned permutation code.
Claim 7
Dependent Claim
47 words
A converter as claimed in claim 4 wherein said means for combining the outputs comprises a coefficient adder in which the outputs of said digital multipliers are combined and a term adder for combining the output of said up-down counter and the output of said coefficient adder.
Claim 8
Dependent Claim
81 words
A converter as claimed in claim 5 wherein the output of the up-down counter is given by the expression where N is the number of stages in the shift register, bn is the delta modulation pulse train, j is the permutation code indexing indicator, M is one-half of N, and R is an integer given by R 1/2W Tau where W is the highest frequency of the message signal to be encoded and 1/ Tau is the delta modulation sampling rate.
Claim 9
Dependent Claim
17 words
A converter as claimed in claim 6 wherein the output of the coefficient adder is given by
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) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |