EP0225641A2
Expired / Lapsed
EP
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AD converting device
Assignee: Advantest Corp
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Filing: 1986-12-10
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Granted: —
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Expires: 2006-12-10
Abstract
Abstract In an AD converting device in which an analog random noise is added by analog adding means (12) to an analog signal (X) to be converted and the added output is converted by an AD converter (15) to a digital signal, an analog offset voltage (0), whose level variation is around (1 to 7) times the quantization step size A of the AD converter, is generated by offset generating means (21) and is also applied to the analog adding means. A random noise waveform is stored in a memory (13), the read-out output of which is converted by DA converting means (14) to an analog random noise having an amplitude about (1 /2 to 6) A, and the converted output is used as the above-said random noise. A digital value of the offset voltage and the digital noise waveform are subtracted from the output of the AD converter, as required.
Inventors
- 👤 Takahiro Yamaguchi
- 👤 Norio Arakawa
- 👤 Takayuki Ohgami
- 👤 Hiromi Kosawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:20
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/06; H03M1/0617; H03M1/0634; H03M1/0636; H03M1/0639; H03M1/0641
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
81 words
An AD converting device in which an analog random noise of a relatively small amplitude is generated by random noise generating means, the analog random noise is added by analog adding means to an analog signal to be converted, and the added output is converted by an AD converter to a digital signal, characterized by the provision of: offset generating means whereby an analog offset voltage of relatively large level variations is generated and is applied to the analog adding means.
Claim 2
Dependent Claim
81 words
An AD converting device in which an analog random noise of a relatively small amplitude is generated by random noise generating means, the analog random noise is added by analog adding means to an analog signal to be converted, and the added output is converted by an AD converter to a digital signal, characterized by the provision of: offset generating means whereby an analog offset voltage of relatively large level variations is generated and is applied to the analog adding means.
Claim 3
Dependent Claim
50 words
The AD converting device according to claim 1, wherein the random noise generating means comprises digital random noise generating means for generating a digital random noise and first DA converting means for converting the digital random noise into the analog random noise to be applied to the analog adding means.
Claim 4
Dependent Claim
48 words
The AD converting device according to claim 2, wherein the digital random noise generating means includes first memory means for storing a digital random noise waveform, the output read out of the first memory means being supplied as the digital random noise to the first DA converting means.
Claim 5
Dependent Claim
40 words
The AD converting device according to claim 3, wherein the offset voltage generating means comprises second memory means for storing a digital offset waveform, and second DA converting means for converting the digital offset waveform into the analog offset voltage.
Claim 6
Dependent Claim
91 words
The AD converting device'according to claim 4, wherein one DA converting means is used both as the first DA converting means and as the second DA converting means and one memory means is used both as the first memory means and as the second memory means, and wherein the digital random noise waveform and the digital offset waveform superimposed on each other are stored in the memory means, which are repeatedly read out therefrom, converted by the DA converting means to analog form, and then applied to the analog adding means.
Claim 7
Dependent Claim
55 words
The AD converting device according to claim 4, further including means for repeatedly reading out the first memory means in synchronization with first clock pulses of a conversion period of the AD converter and means for repeatedly reading out the second memory means by second clock pulses lower in rate than the first clock pulses.
Claim 8
Dependent Claim
38 words
The AD converting device according to claim 1, wherein the offset voltage generating means comprises memory means for storing a digital offset waveform and DA converting means for converting the digital offset waveform to the analog offset voltage.
Claim 9
Dependent Claim
24 words
The AD converting device according to claim 1, wherein the offset generating means is an offset generator for directly generating the analog offset voltage.
Claim 10
Dependent Claim
46 words
The AD converting device according to claim 8, further including AD converting means for converting the analog offset voltage from the offset generator into a digital offset signal and digital subtracting means for subtracting the converted digital offset signal from the output of the AD converter.
Claim 11
Dependent Claim
37 words
The AD converting device according to any one of claims 4 to 7, further including digital subtracting means for subtracting from the output of the AD converter the digital offset waveform read out of the memory means.
Claim 12
Dependent Claim
30 words
The AD converting device according to claim 10, wherein the digital subtracting means performs the subtraction of the digital noise waveform from the output of the AD converter as well.
Claim 13
Dependent Claim
137 words
The AD converting device according to claim 11, comprising: analog dividing means for dividing the level of the input analog signal by a given value; third DA converting means for converting the output of the digital subtracting means into an analog level; analog subtracting means for subtracting the output of the third DA converting means from the input analog signal; switch means selectively supplying the outputs of the analog dividing means and the analog subtracting means to the analog adding means; and combining means for combining the outputs of the digital subtracting means respectively obtainable when the output of the analog dividing means is supplied to the analog adding means and when the output of the analog subtracting means is supplied to the analog adding means, the combined outputs being the output of the AD converting device.
Claim 14
Dependent Claim
39 words
The AD converting device according to any one of claims 1 and 3 to 7, wherein the amplitude of the analog random noise is selected about (1/2 to 6) times the quantization step size A of the AD converter.
Claim 15
Dependent Claim
32 words
The AD converting device according to claim 13, wherein the level variation of the analog offset voltage is about (1 to 7) times the quantization step size Δ of the AD converter.
Claim 16
Dependent Claim
38 words
The AD converting device according to any one of claims 1 and 3 to 8, wherein the level variation of the analog offset voltage is about (1 to 7)times the quantization step size Δ of the AD converter.
References Cited (Backward Citations)
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