Patent US4486876A successfully refreshed from Google Patents.
US4486876A
Expired / Lapsed
US
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Broadband transmission on limited bandwidth digital line
Assignee: Nokia Bell Labs
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Filing: 1982-08-31
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Granted: 1984-12-04
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Expires: 2002-08-31
Abstract
Abstract To insure timing recovery, T carrier requires that the signal contain no more than fifteen consecutive zeros and a "1"s density of at least one out of eight. When a 15 kHz audio program signal is converted into 12-bit words and four words inserted into six 8-bit time slots of the T1 line, timing recovery requirements have been met by using, in addition to an even parity bit, a dedicated "1" bit. Here, instead of the usual eight chords, the compression characteristic used in generating the 12-bit words has only 7 chords, each represented by a combination of three chord bits that always includes at least one "1". This frees the dedicated "1" bit for additional coding detail. Centrally locating the chord bits within the 12-bit word further allows a mix of voice and program channels in the one channel bank. In a disclosed implementation, the analog samples are first converted to 14-bit linear PCM words, and then digitally translated into 12-bit compressed words. The translator includes a ROM addressed by the most significant bits of the 14-bit words. Stored in the ROM at each such address is a table of 12 instruction words. The instruction words direct a switch to select each bit for the 12-bit word, whether to invert it, and whether to include it in parity.
Inventors
- 👤 Wilmer B. Gaunt, Jr.
- 👤 Michael R. Giammusso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:15
CPC Classifications
H; H04; H04J; H04J3/00; H04J3/02; H04J3/04; H04J3/047; H03; H03M; H03M7/00; H03M7/30; H03M7/50
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
57 words
An arrangement for providing timing recovery information in a PCM transmission system comprising: means for converting an input signal into compressed PCM words according to a compression characteristic having linear chords; each chord represented by a combination of chord bits comprising at least one "1", and means for centrally locating said chord bits within said PCM words.
Claim 2
Dependent Claim
57 words
An arrangement for providing timing recovery information in a PCM transmission system comprising: means for converting an input signal into compressed PCM words according to a compression characteristic having linear chords; each chord represented by a combination of chord bits comprising at least one "1", and means for centrally locating said chord bits within said PCM words.
Claim 3
Dependent Claim
98 words
An arrangement for transmitting over an n-bit pulse code modulated transmission system the information contained in amplitude samples of a broadband signal comprising, means for converting said samples into compressed m-bit PCM words according to a compression characteristic having linear chords; each chord represented by a combination of chord bits comprising at least one 1, means for positioning said chord bits centrally within said m-bit words, and means for inserting q of said m-bit words into rn-bit time slots in one frame of said PCM system wherein m is greater than n and q is less than r.
Claim 4
Dependent Claim
98 words
An arrangement for transmitting over an n-bit pulse code modulated transmission system the information contained in amplitude samples of a broadband signal comprising, means for converting said samples into compressed m-bit PCM words according to a compression characteristic having linear chords; each chord represented by a combination of chord bits comprising at least one 1, means for positioning said chord bits centrally within said m-bit words, and means for inserting q of said m-bit words into rn-bit time slots in one frame of said PCM system wherein m is greater than n and q is less than r.
Claim 5
Dependent Claim
99 words
An arrangement for transmitting a broadband audio signal over an 8-bit pulse code modulated (PCM) transmission system comprising means for generating amplitude samples of said audio signal, means for converting said samples into compressed 12-bit PCM words according to a compression characteristic having linear chords, each chord represented by a combination of three chord bits comprising at least one "1", means for positioning said three chord bits between the 5th- and 8th-bit positions inclusive, in said 12-bit words, and means for inserting two of said 12-bit words into three 8-bit time slots in one frame of said PCM system.
Claim 6
Dependent Claim
99 words
An arrangement for transmitting a broadband audio signal over an 8-bit pulse code modulated (PCM) transmission system comprising means for generating amplitude samples of said audio signal, means for converting said samples into compressed 12-bit PCM words according to a compression characteristic having linear chords, each chord represented by a combination of three chord bits comprising at least one "1", means for positioning said three chord bits between the 5th- and 8th-bit positions inclusive, in said 12-bit words, and means for inserting two of said 12-bit words into three 8-bit time slots in one frame of said PCM system.
Claim 7
Dependent Claim
14 words
An arrangement, as in claim 3, wherein said compression characteristic has 11 linear segments.
Claim 8
Dependent Claim
36 words
An arrangement, as in claim 3, wherein said converting means comprises linear analog-to-digital conversion means for converting said analog samples into PCM words longer than 11 bits and digital compression means for compressing said PCM words.
Claim 9
Dependent Claim
14 words
An arrangement, as in claim 3, wherein said 12-bit words comprise one parity bit.
Claim 10
Dependent Claim
13 words
An arrangement, as in claim 3, wherein said parity bit reflects even parity.
Claim 11
Dependent Claim
21 words
An arrangement, as in claim 6, wherein the parity reflected by said parity bit is taken over less than 10 bits.
Claim 12
Dependent Claim
118 words
An arrangement for transmitting an audio program signal over a multiplexed pulse code modulated transmission line having 8-bit time slots occurring at an 8 kHz rate comprising sampling means for sampling said program signal at a multiple of 8 kHz, means for converting the samples from said sampling means into 12-bit words compressed according to a compression characteristic having linear chords, each chord represented by a combination of 3 bits of said 12-bit words, and means for inserting more than one of said 12-bit words into more than two of said 8-bit time slots characterized in that said compression characteristic has seven chords and each combination of 3 chord bits representing a chord includes at least one "1".
Claim 13
Dependent Claim
118 words
An arrangement for transmitting an audio program signal over a multiplexed pulse code modulated transmission line having 8-bit time slots occurring at an 8 kHz rate comprising sampling means for sampling said program signal at a multiple of 8 kHz, means for converting the samples from said sampling means into 12-bit words compressed according to a compression characteristic having linear chords, each chord represented by a combination of 3 bits of said 12-bit words, and means for inserting more than one of said 12-bit words into more than two of said 8-bit time slots characterized in that said compression characteristic has seven chords and each combination of 3 chord bits representing a chord includes at least one "1".
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) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |