US4288873A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analogue to digital converters
Assignee: STC PLC
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Filing: 1979-11-23
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Granted: 1981-09-08
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Expires: 1999-11-23
Abstract
Abstract A p.c.m. encoder comprises a high accuracy linear A/D converter followed by a digital high pass filter, a d.c. offset circuit and a digital compressor. The high pass filter removes any d.c. offset from the encoded signal and the offset circuit then reintroduces a controlled amount of d.c. offset. By this means the performance can be improved especially in regard to idle noise and crosstalk enhancement.
Inventors
- 👤 Michael J. Gingell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:22
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/06; H04B; H04B14/00; H04B14/02; H04B14/04; H04B14/046
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
88 words
A pulse code modulated encoding arrangement comprising a linear analogue-to-digital converter having an input analogue signal coupled thereto and producing pulse code groups each containing a first number of bits, a digital high pass filter to which the analogue-to-digital converter output is applied to remove unwanted dc offset and low frequency components present in said input analogue signal and generated in said analogue-to-digital converter, and means for adding to the high pass filter output a predetermined amount of dc offset for minimizing idle noise and reducing crosstalk enhancement.
Claim 2
Dependent Claim
88 words
A pulse code modulated encoding arrangement comprising a linear analogue-to-digital converter having an input analogue signal coupled thereto and producing pulse code groups each containing a first number of bits, a digital high pass filter to which the analogue-to-digital converter output is applied to remove unwanted dc offset and low frequency components present in said input analogue signal and generated in said analogue-to-digital converter, and means for adding to the high pass filter output a predetermined amount of dc offset for minimizing idle noise and reducing crosstalk enhancement.
Claim 3
Dependent Claim
24 words
An arrangement according to claim 1 including a low pass filtering means interposed between the linear analogue-to-digital converter and the digital high pass filter.
Claim 4
Dependent Claim
21 words
An arrangement according to claim 1 or 2 including means for digitally compressing the filter output containing the added dc offset.
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) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |