US5225835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sigma delta type digital/analog converter system
Assignee: Toshiba Corp
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Filing: 1992-03-27
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Granted: 1993-07-06
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Expires: 2012-03-27
Abstract
Abstract An identical digital signal and a total of k different DC offset signals are provided to the respective ones of a total of k adders. Each of the adders outputs a signal representing the sum of the digital signal and the DC offset signal. The adders are connected to the respective ΣΔ type D/A converters and the output signals of the k type D/A converters are summed up to form a single output signal. Any two of the levels of the DC offset signals given to the k adders differ from each other by equal to or greater than 0.2% of the full scale value of the ΣΔ type D/A converters. With such an arrangement, the performance of the ΣΔ type D/A converters can be remarkably improved without raising the sampling rate and the number of orders of the type D/A converters.
Inventors
- 👤 Shin-ichi Majima
- 👤 Mitsuru Nagata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:03
CPC Classifications
H; H03; H03M; H03M3/00; H03M3/30; H03M3/322; H03M3/324; H03M3/35; H03M1/00; H03M1/66; H03M3/50
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
A ΣΔ type D/A converter system comprising: a total of k adders for receiving an identical digital signal and respective DC offset signals different from one another, each of said adder circuits outputting a signal representing the sum of said digital signal and said DC offset signal; a total of k ΣΔ type D/A converters connected with the respective adders to form a plurality of adder and ΣΔ type D/A converter pairs, the output signals of said adders being converted into corresponding analog signals by the respective ΣΔ type D/A converters; and output means for producing a signal by summing up the output signals of said k ΣΔ type D/A converters.
Claim 2
Dependent Claim
111 words
A ΣΔ type D/A converter system comprising: a total of k adders for receiving an identical digital signal and respective DC offset signals different from one another, each of said adder circuits outputting a signal representing the sum of said digital signal and said DC offset signal; a total of k ΣΔ type D/A converters connected with the respective adders to form a plurality of adder and ΣΔ type D/A converter pairs, the output signals of said adders being converted into corresponding analog signals by the respective ΣΔ type D/A converters; and output means for producing a signal by summing up the output signals of said k ΣΔ type D/A converters.
Claim 3
Dependent Claim
50 words
A ΣΔ type D/A converter system according to claim 1, wherein any two of the levels of the DC offset signals given to said k adding means differ from each other by equal to or greater than 0.2% of the full scale value of said k ΣΔ type D/A converters.
Claim 4
Dependent Claim
95 words
A ΣΔ type D/A converter system according to claim 1, wherein each of said total of k ΣΔ type D/A converters comprises: an adder for adding a digital signal and a feedback signal; a quantizer for quantizing the output signal of said adder; a subtracter for calculating the difference of the output signal of said quantizer and that of said adder; a filter circuit for producing said feedback signal by digitally processing the output signal of said subtracter; and a D/A conversion circuit for converting the output signal of said quantizer into an analog signal.
Claim 5
Dependent Claim
53 words
A ΣΔ type D/A converter system according to claim 1, wherein said output means is provided with a normal output terminal for outputting a normal output signal and an inverted output terminal for outputting an inverted output signal produced by inverting the output signal for each of said k ΣΔ type D/A converters.
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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |