US4012145A — Spectroscopic analysis apparatus employing measur…

Claim 1

Independent Claim 402 words

Apparatus for the spectroscopic analysis of a sample of material for determining the chemical composition of the sample, the apparatus comprising: a coherent radiation source for producing, in succession, respective ones of a plurality of different wavelengths of the coherent radiation, the source having an active material from which there can be produced the said different wavelengths of coherent radiation, reflecting means for reflecting radiation in the source, and a wavelength selecting means operable by variation of its angular orientation relative to the axis of propagation of coherent radiation in the source to sequentially select respective ones of the different wavelengths; a separator for separating the radiation into a measurement portion for irradiating a sample of material and a reference portion; a reference detector arranged to receive the reference portion and to produce a reference signal representing the reference portion; a measurement detector arranged to receive the radiation from the sample of material due to the irradiation of the sample by the measurement portion and to produce a measurement signal representing the said radiation from the sample; and a processing circuit for processing the reference and measurement signals in dependence upon variation of the said angular orientation of the selecting means to produce numerical data relating to the spectral analysis of the sample; said processing circuit comprising: an angular position detecting means for producing position signals representing the angular orientations of the selecting means relative to the said axis of progation: a selector arrangement connected to receive the position signals for producing indicator signals indicating a particular orientation of the selecting means, and thus the production of a particular wavelength of radiation, and indicating that the reference and measurement signals associated with that orientation are to be processed by the processing circuit; a comparator connected to receive the reference signals and operable to produce a comparison signal indicating the presence of a reference signal; first and second, controllable data producing circuits connected to receive the reference and measurement signals respectively to produce analogue signals representing data relating to the spectroscopic analysis of the sample; a trigger arranged to produce, in dependence upon the comparison signal and the indicator signal, a control signal for the data producing circuits; first and second analogue to digital converters connected to receive the analogue signals from the first and second data producing circuits respectively; and an interface circuit connected to receive the said data from the converters.

Claim 2

Dependent Claim 402 words

Apparatus for the spectroscopic analysis of a sample of material for determining the chemical composition of the sample, the apparatus comprising: a coherent radiation source for producing, in succession, respective ones of a plurality of different wavelengths of the coherent radiation, the source having an active material from which there can be produced the said different wavelengths of coherent radiation, reflecting means for reflecting radiation in the source, and a wavelength selecting means operable by variation of its angular orientation relative to the axis of propagation of coherent radiation in the source to sequentially select respective ones of the different wavelengths; a separator for separating the radiation into a measurement portion for irradiating a sample of material and a reference portion; a reference detector arranged to receive the reference portion and to produce a reference signal representing the reference portion; a measurement detector arranged to receive the radiation from the sample of material due to the irradiation of the sample by the measurement portion and to produce a measurement signal representing the said radiation from the sample; and a processing circuit for processing the reference and measurement signals in dependence upon variation of the said angular orientation of the selecting means to produce numerical data relating to the spectral analysis of the sample; said processing circuit comprising: an angular position detecting means for producing position signals representing the angular orientations of the selecting means relative to the said axis of progation: a selector arrangement connected to receive the position signals for producing indicator signals indicating a particular orientation of the selecting means, and thus the production of a particular wavelength of radiation, and indicating that the reference and measurement signals associated with that orientation are to be processed by the processing circuit; a comparator connected to receive the reference signals and operable to produce a comparison signal indicating the presence of a reference signal; first and second, controllable data producing circuits connected to receive the reference and measurement signals respectively to produce analogue signals representing data relating to the spectroscopic analysis of the sample; a trigger arranged to produce, in dependence upon the comparison signal and the indicator signal, a control signal for the data producing circuits; first and second analogue to digital converters connected to receive the analogue signals from the first and second data producing circuits respectively; and an interface circuit connected to receive the said data from the converters.

Claim 3

Dependent Claim 41 words

Apparatus as recited in claim 1, additionally comprising a measurement portion reflector arranged at a predetermined distance from the separator to reflect the measurement portion back to the measurement detector, the said radiation from the sample being the reflected measurement portion.

Claim 4

Dependent Claim 52 words

Apparatus as recited in claim 2, wherein said reflecting means is substantially totally reflective, and the selecting means comprises a dihedral arrangement of a diffraction grating and a plane reflector, the dihedral arrangement being pivotable about an axis coaxial with the intersection of the planes of the grating and said plane reflector.

Claim 5

Dependent Claim 34 words

Apparatus as recited in claim 2, wherein the selecting means comprises another reflector spaced from said reflecting means, and a prism rotatably arranged in the space between said reflecting means and said another reflector.

Claim 6

Dependent Claim 35 words

Apparatus as recited in claim 2, wherein the selecting means comprises a further reflector spaced from said reflecting means, and a rotatable Fabry-Perot system arranged in the space between said reflector and said another reflector.

Claim 7

Dependent Claim 33 words

Apparatus as recited in claim 1, wherein the reflecting means is partially transparent and the selecting means comprises a pivotably arranged diffraction grating, emission of radiation being effected through the said reflecting means.

Claim 8

Dependent Claim 30 words

Apparatus as recited in claim 1, wherein the angular positon detecting means comprises an angular coder operable to produce digital position signals representing the angular orientations of the selecting means.

Claim 9

Dependent Claim 62 words

Apparatus as recited in claim 7, wherein the selector arrangement comprises a counter, connected to receive the digital position signals, for counting the angular orientations of the selecting means, and a decoder arrangement for selecting those angular positions corresponding to the respective ones of the plurality of wavelengths and for selecting at which of those orientations an indicator signal will be produced.

Claim 10

Dependent Claim 17 words

Apparatus as recited in claim 8, wherein the decoder arrangement is pre-programmable to select the angular orientations.

Claim 11

Dependent Claim 118 words

Apparatus as recited in claim 1, wherein the selector arrangement comprises: a counter for counting angular orientations of the selecting means; logical decoder circuits connected to decode signals from the counter representing a predetermined number of angular orientations of the selecting means at which coherent radiation could be produced from the source; and a plurality of decoding circuits connected to the logical decoder circuits, the decoding circuits constituting logical OR gates having a total number of input circuits equal to the said predetermined number of angular orientations, the input circuits incorporating respective control arrangements whereby they can be manually rendered operative or inoperative in order to program the selector arrangement to select certain ones of the angular orientations.

Claim 12

Dependent Claim 35 words

Apparatus as recited in claim 10, wherein each control arrangement is constituted by spaced apart end portions of two conductors adapted to be bridged by a further conductor to render the associated input circuit operative.

Claim 13

Dependent Claim 63 words

Apparatus as recited in claim 10, further comprising synchronisation signal producing means for producing, from signals produced by the counter, a synchronisation signal for synchronising the operation of the processing circuit with the variation of angular orientation of the selecting means and for producing, from signals produced by the counter and by operative ones of the said input circuits, the said indicator signals.

Claim 14

Dependent Claim 30 words

Apparatus as recited in claim 1, comprising a delay circuit, wherein the second data producing circuit is connected to receive the control signal from the trigger via the delay circuit.

Claim 15

Dependent Claim 14 words

Apparatus as recited in claim 13, wherein each data producing circuit comprises an integrator.

Claim 16

Dependent Claim 15 words

Apparatus as recited in claim 1, wherein each dta producing circuit comprises a peak detector.

Claim 17

Dependent Claim 59 words

Apparatus as recited in claim 12, comprising amplifiers respectively connected to receive the reference and measurement signals and to feed them to the respective first and second data producing circuits, each amplifier comprising drift control means, for controlling drift of the output of the amplifier, the drift control means being arranged to be triggered by the said synchronisation signal.

Claim 18

Dependent Claim 153 words

Apparatus as recited in claim 16, wherein each data producing circuit comprises an integrator, the integrator comprising: a monostable for regulating the integration period, having an input connected to receive the control signal from the trigger and two outputs; an analogue gate an input of which is connected to one of the outputs of the monostable; an integration amplifier having two inputs one of which is connected to the output of the analogue gate; a shift control circuit connected to the other input of the integration amplifier; a flip-flop for resetting the integrator to zero having an input connected to the other output of the monostable and another input for receiving a reset to zero signal; and a further analogue gate having an output connected to the said one input of the integration amplifier, and having inputs connected to the output of the flip-flop and to the output of the integration amplifier respectively.

Claim 19

Dependent Claim 85 words

Apparatus as recited in claim 1, wherein each analogue to digital converter comprises an output for producing a signal indicating the end of a conversion period, and wherein each of the data producing circuits comprises an input for receiving a reset to zero signal for resetting the data producing circuit, the apparatus further comprising an AND gate for receiving the signals from the converters indicating end of a conversion period and for producing therefrom the reset to zero signal for resetting the data producing circuits.

Claim 20

Dependent Claim 63 words

Apparatus as recited in claim 1, wherein the analogue to digital converters are operable in dependence, upon the production of a cmparison signal, the apparatus further comprising a restoring circuit for producing a conversion rigger signal for triggering the digital to analogue converters to operate when an indicator signal has been produced by the selector arrangement and no comparison signal has been produced.

Claim 21

Dependent Claim 118 words

Apparatus as recited in claim 19, further comprising a pulse generator for converting the indicator signal to a square-wave gating signal the restoring circuit comprising: first and second pulse generators respectively adapted to be triggered by the leading and trailing edges of the square-wave pulse; a flip-flop having a preset input connected to the output of the first pulse generator and a clear input connected to the output of the said trigger which is connected to receive the comparison signal and the square-wave pulse; an AND gate, having a first input connected to the output of the second pulse generator and a second input connected to an output of the flip-flop, for producing the said conversion trigger signal.

Claim 22

Dependent Claim 23 words

Apparatus as recited in claim 20, further comprising an OR gate connected to receive the conversion trigger signal and to control the converters.

Claim 23

Dependent Claim 59 words

Apparatus as recited in claim 1, further comprising a store for storing measurement data; a store for storing reference data; calculating means for calculating the ratio of the value of measurement data to the value of reference data; and data read-out means; the stores, calculating means and data read-out means being connected to receive data from the interface circuit.

Claim 24

Dependent Claim 19 words

Apparatus as recited in claim 1, wherein the source comprises a laser having a gaseous or liquid active material.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-03-14	1980-09-13	1981-03-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-03-14	1984-09-13	1985-03-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-03-14	1988-09-13	1989-03-15	$7700.00	Window Closed / Lapsed

Spectroscopic analysis apparatus employing measurement and reference radiation

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