Patent US3711650A successfully refreshed from Google Patents.
US3711650A
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Adaptive pulse code modulation system
Assignee: Northrop Grumman Information Technology Inc
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Filing: 1970-10-26
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Granted: 1973-01-16
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Expires: 1990-10-26
Abstract
Abstract An adaptive pulse code modulation system useful for increasing the channel capacity of a fixed bandwidth communication link. Channel capacity is increased by reducing the redundancy normally characteristic of known non-adaptive pulse code modulation systems. In the subject adaptive system, the space in a fixed bit length frame is variable allocated to multiple channels on a frame-by-frame basis. That is, each channel is assigned only the number of frame bits actually required to transmit a representation of that channel''s digital sample during a particular frame interval. The frame bit space is primarily allocated between a fixed bit length format field and a fixed bit length sample field. The format field is comprised of as may format numbers as there are channels. Each format number is of fixed bit length and expresses the bit position of the most significant ''''1'''' in the digital sample of a particular channel. Thus, for example, if 256 different analog levels are to be quantized for each channel, an 8-bit digital sample would be available from each channel. In this case, three bit format numbers are used so that a format number can identify any bit position within the 8-bit digital sample. The aforementioned sample field is comprised of a plurality of variable bit length sample numbers, each associated with a different channel. The sample numbers are comprised of bits which substantially match the bits less significant than the most significant ''''1'''' in the corresponding digital sample.
Inventors
- 👤 T Kuhn
- 👤 N Seitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:44
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/16; H04J3/1682; H04J3/1688
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
98 words
A system for communicating information from a plurality (n) of channels at a transmitting station, whereat said information from each channel is represented by a digital sample comprised of k bits, to a receiving station, said system comprising: means at said transmitting station for forming n multibit format numbers, each format number uniquely identifying the bit position of the most significant ''''1'''' in one of said n digital samples; and means forming a multibit output word comprised of said n format numbers and the bits in said n digital samples less significant than the most significant ''''1'''' therein.
Claim 2
Independent Claim
98 words
A system for communicating information from a plurality (n) of channels at a transmitting station, whereat said information from each channel is represented by a digital sample comprised of k bits, to a receiving station, said system comprising: means at said transmitting station for forming n multibit format numbers, each format number uniquely identifying the bit position of the most significant ''''1'''' in one of said n digital samples; and means forming a multibit output word comprised of said n format numbers and the bits in said n digital samples less significant than the most significant ''''1'''' therein.
Claim 3
Independent Claim
171 words
A system for communicating information from a plurality (n) of channels at a transmitting station, whereat said information from each channel is represented by a digital sample comprised of k bits, to a receiving station, said system comprising: means at said transmitting station for forming n multibit format numbers, each format number uniquely identifying the bit position of the most significant ''''1'''' in one of said n digital samples; means for determining the total number of bits in said n digital samples less significant than the most significant ''''1''''s therein; means for comparing said total number of less significant bits with a predetermined bit length less than nk bits; means responsive to said comparing means indicating that said total number of less significant bits is greater than said predetermined bit length for processing said total number of less significant bits to reduce the number thereof to said predetermined bit length; and means forming a multibit output word comprised of said n format numbers and said reduced number of less significant bits.
Claim 4
Independent Claim
171 words
A system for communicating information from a plurality (n) of channels at a transmitting station, whereat said information from each channel is represented by a digital sample comprised of k bits, to a receiving station, said system comprising: means at said transmitting station for forming n multibit format numbers, each format number uniquely identifying the bit position of the most significant ''''1'''' in one of said n digital samples; means for determining the total number of bits in said n digital samples less significant than the most significant ''''1''''s therein; means for comparing said total number of less significant bits with a predetermined bit length less than nk bits; means responsive to said comparing means indicating that said total number of less significant bits is greater than said predetermined bit length for processing said total number of less significant bits to reduce the number thereof to said predetermined bit length; and means forming a multibit output word comprised of said n format numbers and said reduced number of less significant bits.
Claim 5
Dependent Claim
28 words
The system of claim 2 including n k-bit sample registers; and means for storing each of said k-bit digital samples in a different one of said sample registers.
Claim 6
Dependent Claim
83 words
The system of claim 3 wherein said means for forming said format numbers includes a counter; means for resetting said counter to a count of K; and logic means for sequentially coupling said sample registers to said counter, said logic means including means for serially examining the bits of each of said stored samples in order from least to most significant and for resetting said counter in response to a ''''1'''' bit and for decrementing said counter in response to a ''''0'''' bit.
Claim 7
Dependent Claim
25 words
The system of claim 3 wherein said means for processing includes means for dropping the least significant bit from said n sample registers in sequence.
Claim 8
Dependent Claim
67 words
The system of claim 3 including a format number register; and wherein said means for forming format numbers includes means for sequentially loading said format numbers into said format number register during n successive format intervals; and wherein said comparing means includes a sum register; and means for adding each of said format numbers loaded into said format number register to the content of said sum register.
Claim 9
Dependent Claim
44 words
The system of claim 6 wherein said comparing means includes means for presetting said sum register to a predetermined negative count; and decoder means for examining the sign of the sum register content n format intervals subsequent to the presetting of said sum register.
Claim 10
Dependent Claim
37 words
The system of claim 6 wherein said means forming an output word includes an output register; and means for loading said format numbers into said output register in concert with said loading into said format number register.
Claim 11
Dependent Claim
41 words
The system of claim 6 wherein said means for processing includes means for sequentially decrementing said formant numbers stored in said format number register and for sequentially dropping the least significant bit of the corresponding samples stored in said sample register.
Claim 12
Dependent Claim
21 words
The system of claim 9 including means for decrementing said sum register each time one of said format numbers is decremented.
Claim 13
Dependent Claim
74 words
The system of claim 10 wherein said means forming an output word includes an output register; means for loading said format numbers into said output register in concert with said loading into said format number register; and means active subsequent to said means for processing for transferring from each of said sample registers to said output register, a number of bits equal to the value of the corresponding number in said format number register.
Claim 14
Dependent Claim
115 words
In a communication system, a subsystem for representing n k-bit digital samples in a multibit frame comprised of less than nk bit positions, said means including: means for determining the position of the most significant ''''1'''' in each of said digital samples and for forming n i-bit format numbers, each identifying the position of said most significant ''''1'''' in one of said n samples; an output register; means for storing said n format numbers in said output register; and means for extracting bits from each of said digital samples less significant than the bit position identified by the format number associated with that sample; and means for storing said extracted bits in said output register.
Claim 15
Dependent Claim
115 words
In a communication system, a subsystem for representing n k-bit digital samples in a multibit frame comprised of less than nk bit positions, said means including: means for determining the position of the most significant ''''1'''' in each of said digital samples and for forming n i-bit format numbers, each identifying the position of said most significant ''''1'''' in one of said n samples; an output register; means for storing said n format numbers in said output register; and means for extracting bits from each of said digital samples less significant than the bit position identified by the format number associated with that sample; and means for storing said extracted bits in said output register.
Claim 16
Dependent Claim
38 words
The subsystem of claim 12 including means for determining whether the sum of said ni format number bits plus said bits from said digital samples less significant than the bit positions identified by said format numbers exceeds nk.
Claim 17
Dependent Claim
44 words
The subsystem of claim 13 wherein said means for extracting bits includes means responsive to said sum exceeding nk for corresponding said bits from said digital samples less significant than the bit positions identified by said format numbers to reduce said sum to nk.
Claim 18
Dependent Claim
57 words
The subsystem of claim 14 wherein said means for compressing includes means for dropping the least significant bit from each of said samples in sequence until the sum of said ni format number bits plus the remaining bits from said digital samples less significant than the bit positions identified by said format numbers is equal to nk.
Claim 19
Dependent Claim
24 words
The subsystem of claim 15 including regeneration means responsive to the bits stored in said output register for regenerating said k bit digital samples.
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) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |