Method and device for synchronizing on an outside event the sampling of measuring signals through a digitizing assembly of the oversampling type
First Claim
1. A device for synchronizing sampling of measuring signals with a reference signal marking an outside event, said device comprising a digitizing assembly including an analog to digital converter of the over-sampling type, a clock for producing a synchronization signal, and a digital filter adapted for producing, from the measuring signals and with a fixed period which is a multiple of a sampling period, a series of validated samples, each validated sample resulting from summation of a determined number n of samples from the analog to digital converter;
- and shifting means for forcing production, by the digital filter, of one series of validated samples, the first sample of said one series of validated samples corresponding to a sample taken on an input signal with a shift independent of the reference signal.
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Abstract
A digitalization assembly of the over-sampling type includes an analog to digital converter (2) producing at a frequency F=kf small-format p samples and a digital filter (3) which, through the summation of a certain number n of over-samples, produces validated larger P-format samples at the frequency f, at instants fixed by a clock. In order to readjust the sampling instants in relation to an outside event which can occur at any time, a temporary memory store (5) is inserted between the converter (2) and the filter (3) and, according to the instant of arrival of this event, the appropriate samples to be sent towards the filter for their summation are selected.
41 Citations
18 Claims
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1. A device for synchronizing sampling of measuring signals with a reference signal marking an outside event, said device comprising a digitizing assembly including an analog to digital converter of the over-sampling type, a clock for producing a synchronization signal, and a digital filter adapted for producing, from the measuring signals and with a fixed period which is a multiple of a sampling period, a series of validated samples, each validated sample resulting from summation of a determined number n of samples from the analog to digital converter;
- and shifting means for forcing production, by the digital filter, of one series of validated samples, the first sample of said one series of validated samples corresponding to a sample taken on an input signal with a shift independent of the reference signal.
- View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for synchronizing, with a common reference signal marking an outside event, sampling of measuring signals respectively by a plurality of signal digitizing assemblies, each assembly comprising an analog to digital converter of the over-sampling type, a clock producing synchronization signals, and a digital filter adapted for producing from the measuring signals and with a fixed period a series of validated samples resulting from summation of a sequence of n successive samples coming from the analog to digital converter and obtained by over-sampling, said method comprising:
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storing a determined number N of samples greater than a number n of each sequence of samples coming from each one of said analog to digital converters before being applied to the corresponding digital filter, and selecting among permanently stored N samples of each measuring signal a time shifted sequence of n successive samples, so that a corresponding validated sample coming from each digital filter corresponds to a sample taken on each signal with a shift independent of the reference signal and substantially the same for all the digitizing assemblies. - View Dependent Claims (9)
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10. An analog-to-digital converting system comprising:
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at least one digitizing assembly including an over-sampling converter means for producing from analog signals to be converted a series of low resolution digital signals;
clock means for generating an over-sampling clock signal; and
a digital filter means for summing up a determined number of said low resolution digital signals, said digital filter means producing in succession from said series higher resolution digital words with a fixed period which is a multiple of the period of the over-sampling clock signals; andmeans for synchronizing with a reference signal marking occurrence of an outside event, production of validated digital words by said digital filter means, said synchronizing means comprising shifting means for forcing production by said digital filter means of validated digital words, a first produced validated digital word corresponding to a sample picked up on the analog signals with a shift independent of said reference signal.
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11. An analog-to-digital converting system comprising:
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a digitizing assembly including an over-sampling converter means for producing from analog signals to be converted a series of low resolution digital signals;
clock means for generating an over-sampling clock signal; and
a digital filter means for summing up a determined number of said low resolution digital signals, said digital filter means producing in succession from said series higher resolution digital words with a fixed period which is a multiple of the period of the over-sampling clock signals; andmeans for synchronizing with a reference signal, marking occurrence of an outside event, production of validated digital words by said digital filter means, said synchronizing means comprising shifting means for forcing production by said digital filter means of validated digital words, a first produced validated digital word corresponding to a sample picked up on the analog signals with a shift less than the fixed period.
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12. An analog-to-digital converting system comprising:
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at least one digitizing assembly including an over-sampling converter means for producing from analog signals to be converted a series of low resolution digital signals;
clock means for generating an over-sampling clock signal; and
a digital filter means for summing up a determined number of said low resolution digital signals, said digital filter means producing in succession from said series higher resolution digital words with a fixed period which is a multiple of the period of the over-sampling clock signals; andmeans for synchronizing with a reference signal, marking occurrence of an outside event, production of validated digital words by said digital filter means, said synchronizing means comprising shifting means for forcing production by said digital filter means of validated digital words, said shifting means including a memory means for a number N of low resolution digital signals greater than a number n of low resolution digital signals to be received and summed by said digital filter means to produce a digital word, and a control assembly for controlling at reception of said reference signal, selective extraction of said low resolution digital signals selected according to the time of reception and transfer thereof into said digital filter means, whereby a first produced validated digital word validated after said reception time corresponds to a sample picked up on said analog signals with a shift less than a predetermined number of periods of said over-sampling clock signal. - View Dependent Claims (13, 14, 15)
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16. A converting system as claimed in 12, wherein said memory means comprises a F.I.F.O. type memory and a delay line for applying to low resolution digital words transmitted to said digital filter means a delay at most equal to the time for sampling said N low resolution digital words.
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17. A method of synchronizing with a common reference signal marking an outside event production from analog signals of validated digital words by a plurality of signal digitizing assemblies, each assembly including an over-sampling converter means for producing from analog signals to be converted a series of low resolution digital signals, clock means for generating an over-sampling clock signal, and a digital filter means for summing up a determined number n of said low resolution digital signals, said digital filter means producing in succession from said series higher resolution digital words with a fixed period which is a multiple of the period of the over-sampling clock signals, said method comprising:
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storing a determined current number N of low resolution digital signals greater than said determined number n of low resolution digital signals from each one of said over-sampling converter means before being applied to the associated digital filter means; selecting among the N current low resolution digital signals stored for each analog signal a time shifted sequence of n of said digital signals, so that the resulting validated digital word issuing from each digital filter means corresponds to a sample picked up on each analog signal with a shift independent of the time of arrival of said reference signal and substantially the same for all the digitizing assemblies. - View Dependent Claims (18)
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Specification