Patent US3609552A successfully refreshed from Google Patents.
US3609552A
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Differential pulse code communication system using digital accumulation
Assignee: AT&T Inc
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Filing: 1969-08-20
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Granted: 1971-09-28
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Expires: 1989-08-20
Abstract
Abstract A differential pulse code communication system is disclosed which digitally accumulates the difference signal in order to eliminate the matching problem inherent in prior art systems. In the transmitter the difference signals are digitally accumulated and converted to analog form for subtraction from the input signal, and at the receiver the difference signal is accumulated before it is converted to analog form to reconstruct the input signal.
Inventors
- 👤 John O Limb
- 👤 Frank W Mounts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:37
CPC Classifications
H; H03; H03M; H03M3/00; H03M3/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
166 words
A differential pulse code communication system comprising: a source of an analog message wave, means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for quantizing said difference signal into a predetermined number of discrete levels, means for producing a first digital signal representative of the amplitudes of each of the levels of said quantized difference signal, accumulating means For accumulating the digits of said first digital signal, means connected to said accumulating means for producing said feedback signal by converting said accumulated digital signal to a corresponding analog signal, means for encoding and transmitting said quantized difference signal, means for receiving said transmitted difference signal, means for producing a second digital signal representative of the amplitudes of each of the levels of said transmitted difference signal, means for accumulating the digits of said second digital signal, and means for converting said accumulated digital signal to analog form in order to reconstruct said analog message wave at the receiver.
Claim 2
Dependent Claim
166 words
A differential pulse code communication system comprising: a source of an analog message wave, means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for quantizing said difference signal into a predetermined number of discrete levels, means for producing a first digital signal representative of the amplitudes of each of the levels of said quantized difference signal, accumulating means For accumulating the digits of said first digital signal, means connected to said accumulating means for producing said feedback signal by converting said accumulated digital signal to a corresponding analog signal, means for encoding and transmitting said quantized difference signal, means for receiving said transmitted difference signal, means for producing a second digital signal representative of the amplitudes of each of the levels of said transmitted difference signal, means for accumulating the digits of said second digital signal, and means for converting said accumulated digital signal to analog form in order to reconstruct said analog message wave at the receiver.
Claim 3
Dependent Claim
97 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a general feedback signal from said message wave, means for quantizing said difference signal into a predetermined number of discrete levels, means for producing a digital signal representative of the amplitudes of each of the levels of said quantized difference signal, accumulating means for accumulating the digits of said digital signal, and means connected to said accumulating means for producing said feedback signal by converting said accumulated digital signal to a corresponding analog signal.
Claim 4
Dependent Claim
97 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a general feedback signal from said message wave, means for quantizing said difference signal into a predetermined number of discrete levels, means for producing a digital signal representative of the amplitudes of each of the levels of said quantized difference signal, accumulating means for accumulating the digits of said digital signal, and means connected to said accumulating means for producing said feedback signal by converting said accumulated digital signal to a corresponding analog signal.
Claim 5
Dependent Claim
114 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for sampling said difference signal, means for dividing said sampled signal into a predetermined number of discrete signal levels, means for assigning a first digital code to each of the levels of said discrete signal, means for converting said first digital code to a second digital code representative of the amplitudes of said signal levels, means for accumulating the digits of said second digital code, and means for converting the accumulated signal to analog form in order to produce said feedback signal.
Claim 6
Dependent Claim
114 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for sampling said difference signal, means for dividing said sampled signal into a predetermined number of discrete signal levels, means for assigning a first digital code to each of the levels of said discrete signal, means for converting said first digital code to a second digital code representative of the amplitudes of said signal levels, means for accumulating the digits of said second digital code, and means for converting the accumulated signal to analog form in order to produce said feedback signal.
Claim 7
Dependent Claim
179 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for sampling said difference signal, means for dividing said sampled signal into a predetermined number of discrete signal levels, means responsive to each level of said sampled signal for producing a binary code having distinct groups of bits, each group of bits corresponding to a level of said sampled signal, a first bit in said group indicating the polarity of the level and the remainder of the bits in said group indicating the amplitude of the level, accumulating means for accumulating the groups of bits in said binary code, each of said groups being added digitally in said accumulating means when a positive level is indicated by said first bit, and each of said groups being subtracted digitally in said accumulating means when a negative level is indicated by said first bit, and means for converting the accumulated signal to analog form to produce said feedback signal
Claim 8
Dependent Claim
179 words
In a system for transmitting coded difference samples of a message wave, apparatus which comprises: means for producing a difference signal by subtracting a generated feedback signal from said message wave, means for sampling said difference signal, means for dividing said sampled signal into a predetermined number of discrete signal levels, means responsive to each level of said sampled signal for producing a binary code having distinct groups of bits, each group of bits corresponding to a level of said sampled signal, a first bit in said group indicating the polarity of the level and the remainder of the bits in said group indicating the amplitude of the level, accumulating means for accumulating the groups of bits in said binary code, each of said groups being added digitally in said accumulating means when a positive level is indicated by said first bit, and each of said groups being subtracted digitally in said accumulating means when a negative level is indicated by said first bit, and means for converting the accumulated signal to analog form to produce said feedback signal
Claim 9
Dependent Claim
142 words
In a system for receiving coded difference samples of a message wave, apparatus which comprises: means responsive to the coded difference samples for producing binary binary code having distinct groups of bits, each group of bits corresponding to the level of one of said samples, a first bit in said group indicating the polarity of the sample and the remainder of the bits in said group indicating the amplitude of the sample, accumulating means for accumulating the groups of bits in said binary code, each of said groups being added digitally in said accumulating means when a positive level is indicated by said first bit and each of said groups being subtracted digitally in said accumulating means when a negative level is indicated by said first bit, and means for converting said accumulated signal to analog form to reconstruct said message wave.
Claim 10
Dependent Claim
142 words
In a system for receiving coded difference samples of a message wave, apparatus which comprises: means responsive to the coded difference samples for producing binary binary code having distinct groups of bits, each group of bits corresponding to the level of one of said samples, a first bit in said group indicating the polarity of the sample and the remainder of the bits in said group indicating the amplitude of the sample, accumulating means for accumulating the groups of bits in said binary code, each of said groups being added digitally in said accumulating means when a positive level is indicated by said first bit and each of said groups being subtracted digitally in said accumulating means when a negative level is indicated by said first bit, and means for converting said accumulated signal to analog form to reconstruct said message wave.
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) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |