US3810020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Encoder-decoder for pcm systems
Assignee: Nokia of America Corp
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Filing: 1972-06-05
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Granted: 1974-05-07
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Expires: 1992-06-05
Abstract
Abstract High accuracy at low signal amplitudes is achieved in the encoder section of an encoder-decoder for PCM signals together with low cost by using a feedback linear encoder with a digital compandor, dividing the companding scale into two ranges having an equal number of segments, providing a separate comparator for each range, and using the same set of weights for both comparators. A shift weight is provided to go from the low-level comparison to the high-level comparison, and a ratio-producing network is provided to multiply the effect of each weight by the appropriate expansion factor in the high-level comparator as compared to the low-level comparator.
Inventors
- 👤 A Fortuna
- 👤 H Persson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:20
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/02; H03M1/12; H03M1/50; H03M1/504
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
84 words
Apparatus for encoding amplitude-modulated signal samples into PCM signals, comprising: a. a sample input; b. a source of comparison signals; c. separate high-level and low-level comparator means for comparing said sample to said comparison signals; D. clocked logic means for successively producing comparison signals of predetermined amplitudes and for storing the results of a predetermined number of successive comparisons between said sample and said comparison signals; and e. parallel-to-serial converter means for sequentially reading out said stored results to form a PCM signal output.
Claim 2
Dependent Claim
84 words
Apparatus for encoding amplitude-modulated signal samples into PCM signals, comprising: a. a sample input; b. a source of comparison signals; c. separate high-level and low-level comparator means for comparing said sample to said comparison signals; D. clocked logic means for successively producing comparison signals of predetermined amplitudes and for storing the results of a predetermined number of successive comparisons between said sample and said comparison signals; and e. parallel-to-serial converter means for sequentially reading out said stored results to form a PCM signal output.
Claim 3
Dependent Claim
82 words
The apparatus of claim 1, in which said logic means include a weighting network containing weights combinable to produce one-half of said comparison signals and further containing a shift weight; said apparatus further comprising ratioing means connected to feed to said low-level comparator the difference between said sample and said comparison signals, and to feed to said high-level comparator the difference between said sample and said comparison signals times a predetermined multiplier augmented by a shift signal determined by said shift weight.
Claim 4
Dependent Claim
41 words
The apparatus of claim 2, in which said logic means further include means to select for storage the output of either said low-level or said high-level comparator means, and to activate said shift weight whenever said high-level comparator means is selected.
Claim 5
Dependent Claim
69 words
The apparatus of claim 3, in which said logic is arranged to select said low-level comparator means for the determination of the sign bit of each sample, said high-level comparator means for the determination of the most significant bit, and either said high-level or said low-level comparator means for the determination of all other bits, depending upon whether the most significant bit is determined to be 0 or 1.
References Cited (Backward Citations)
US3071727A
Cited
US3609551A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |