SU1167445A1 - Spectrometer - Google Patents

Abstract

A SPECTROMETER, comprising an optical device containing an optically coupled radiation source, a three-stroke optical switch for sequentially directing the radiation flux into the optical system of the reference channel, into the optical system of the sample channel Iv radiation absorber, two-way optical switch, monochromator and photo receiving device, measuring device containing analog -digital converter (ADC), background correction device, information display device, memorization of a sig device A comparison and a reference voltage generator, a synchronization device containing a clock sensor and a cycle sensor connected to a three-stroke optical switch, while the output of the photoreceiver is connected: to the first input ADC whose output is connected to the first inputs of the information display device, the background correction device and a memory device, and the output of the background correction device is connected to an electrical input of the photoreception device, characterized in that, in order to increase speed, the meter The device has a reference switch and a comparator, the switch inputs are connected to the output of the reference voltage generator and to the memory output of the comparison signal, and the switch output is connected to the reference input of the comparator, the comparator and generator outputs of reference voltages, a logical cell NAND and three Htrigger, whose installation inputs are connected to the output of the cycle sensor, and the synchronous inputs connected to the output of the clock sensor, while the direct output of the first trigger is connected to the second input of the background correction device and to the data input of the second trigger, direct output) the second trigger is connected to the control input of the memory of the comparison signal and to the first input of the logical the NAND cell, the inverse of its output is connected to the data input of the first trigger, the forward output of the third trigger is connected to the control input of the reference switch and the second input of the information display device, The logical cell is NOT connected to the output of the comparator, its output is connected to the data input of the third trigger, and the output of the clock sensor is connected to the third input of the ADC.

Description

The invention relates to spectral instrumentation and can be used to create spectrometers and spectrophotometers with digital processing of measurement results and to obtain at the output a value of transmittance, reflection or other optical characteristics depending on the wavelength. The aim of the invention is to improve the speed. The drawing shows the principal scheme of the proposed spectrometer. The main parts of the spectrometer are optical device 1, synchronization device 2, measuring device 3. The optical device consists of 4 radiation sources, a two-channel optical system of two pairs of concave mirrors 5, 6 and 7.8, and mirrors 5 and 6 form the sample channel, and 7 and 8 comparison channel, a three-stroke optical switch based on a rotary mirror 9 with a drive 10 and a two-stroke switch 11 connected to it, a monochromator 12 and a photoreceiver 13 connected to the measuring device 3. In addition to In addition, the optical device 1 is provided with an absorber of radiation 14. The synchronization device 2 in the spectrometer contains a sensor of 15 cycles and a sensor of 16 cycles of operation of the optical switch, three D-flip-flops 17 18 and 19 and a logical cell AND-NOT 20 The installation inputs of all D-flip-flops 17 18 and 19 are connected to the sensor output 15. cycles , and their synchronization moves C - to the sensor output of 16 cycles. I The direct output of the first trigger 17 is connected to the data input D of the second trigger 18, the inverse output of the second trigger 18 to the input D of the first trigger 17, the first input of the AND-NO cell 20 is connected to the direct output of the second trigger 18, and its output - with the input D of the third trigger data 19, The measuring system 3 of the spectrometer is based on the A / D converter 21, the output of which is connected with the input data of the information display device 22, the background correction device 23 and the storage register 24 included in the digital-analog converter (D / A) 25, which is issued A total of functions of the memory of the comparison signal. The CL 25 is connected to one of the switched inputs of the switch 26 of the reference signal and to the comparison input of the comparator 27. The second switching input of the switch 26 of the reference signal is connected to one of the outputs of the generator 28 of the reference voltages. The output of the switch 26 is connected to the reference input of the ADC 21, and the second output of the generator 28 of the reference voltage is connected to the second reference input of the comparator 17. The output of the comparator 27 is connected to the second input of the AND-NE cell 20. The direct outputs of the trigger 17 and 18 are connected to the control inputs the background correction device 23 and the DAC 25, or rather its storage register 24, respectively, and the direct output of the trigger 19 with the control inputs of the information display device 22 and the switch 26 of the reference signals. The operation of the device in the spectrophotometer mode is carried out as follows. The measurement cycle consists of three clocks, corresponding to the installation of the mirror 9 of the optical switch in one of three fixed positions, which is accompanied by the issuance of a synchronization signal from the sensor of 16 clocks. Each cycle is triggered by a signal coming from a sensor of 15 cycles with a weak lead in relation to the first clock pulse. When the signal from the sensor reaches 15 cycles, the measuring system is reset, i.e. triggers 17, 18, and 19 are set to state 1, | At the same time, the logical control 1 signals are sent to the control inputs of the background correction device 29 of the memory register 24 and the display device, which will reset the data recorded in them. In addition, under the action of the same signal, the switch 26 of the reference signal will connect the generator's output 28 to the reference voltage to the ADC reference input 21, and a logical signal O will arrive at the data input of the trigger 17 from the inverse output of the trigger 18. As a result of resetting the data of the storage register 24 to the input equal to comparator 27 will receive a zero signal, significantly smaller than the signal at its reference input, which will result in logical O, at the second input of the IS-NOT 20 cell and, consequently, logical 1 to the trigger data input 19. The first ta ct work corresponds to the measurement of the background. The mirror 9 of the optical switch is then set to the position shown in the drawing, so that the radiation flux from the source 1 is interrupted and directed by this mirror to the radiation absorber 11. When the signal from the sensor reaches 16 clocks at the synchronization inputs of the trigger 17, 18 and 19, only the trigger 17 switches to the state O, the data input of which has been set to logical O. Logic O from the trigger output 17 goes to the data input of the trigger 18, as well as will open the background correction device 23, on the data input of which the background code will come from the output of the ADC 21, also launched by the sensor pulse 16. An analog signal from the output of the background correction device 23 will go to the correction input of the photodetector ycT 13. In the second These measure the standard sample. Mirror 9 of the optical switch directs the radiation from source 1 to the comparison channel 7, 8, in which a standard sample is installed. The radiation transmitted through this sample is sent by the optical switch 11 to the monochromator 12 and further to the photoreceiver 13. In this case, the signal generated by the receiver entering device 13 will be equal to the sum of the signals corresponding to the transmission of the standard sample and the background. From this signal, the background signal, subtracted in the previous cycle from the correction device, will be subtracted; therefore, in the second cycle, the signal to the ADC receives a signal corresponding to the intensity of the radiation passing through the standard sample. Synchronously with the installation of mirrors from the sensor to the ADC and the triggers, a second clock pulse arrives, which triggers the ADC and sets the trigger to the Logic O state. A logical signal S from its direct output opens the memory register, which stores the digital code received from LSA. At the same time, the logical O from the trigger enters the first input of the NAND cell. Logic 1 from the inverse of the trigger output to the end of the second clock pulse is fed to the D input of the trigger data and sets it to Logic 1. The code entered into the storage register, in the form of an analog signal, is fed from the output of the DAC to one of the switched inputs of the reference signal switch and to the comparator input. If the value of the comparison signal at the comparator input is greater than the specified value supplied to its reference input from the reference voltage generator, then the logical 1 output is set at the comparator output. As a result, the NAND cell is opened and the logical O input to the trigger data D. In this case, the logical 1 is saved on this output. .-. When the third clock pulse arrives from sensor 16 and a logical O is present at input D of trigger data 19, it is set to Logic O. The information display device 22 opens at a signal from Logical O from its output, and the rotary signal switch 26 switches the reference input of ADC 21 from the generator 28 reference voltages to the output of the DAC 25, at which the signal corresponding to the standard sample is stored from the previous clock cycle. Due to this, the code at the output of the ADC 21, triggered by the third clock pulse, will correspond not to the signal from the sample channel, but to the ratio of the signals of the test and standard samples, i.e. the final result of the value of the transmission of the sample. In addition, since the maximum value of the ADC code corresponds to the voltage applied to its reference input, in the proposed spectrometer the maximum resolution of the ADC is realized at any signal level in the reference channel. Due to this, errors are eliminated due to incomplete use of the ADC resolution. 5 If the comparison signal in the second cycle was less than the specified one (logic is set at the D input of the trigger data 19), this trigger does not switch and the formation information display 22 remains blocked. After the end of the third cycle, the 15-cycle sensor enters the next 5 pulse, and the described measurement process is repeated.

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Claims (1)

SPECTROMETER, including an optical device containing an optically coupled radiation source, a three-cycle optical switch for sequentially directing the radiation flux into the optical system of the comparison channel, into the optical system of the sample channel, an radiation absorber, two-stroke optical switch, a monochromator and a photodetector, a measuring device containing an analog digital converter (ADC), background correction device, information display device, signal storage device signals and a reference voltage generator, a synchronization device containing a clock sensor and a cycle sensor associated with a three-stroke optical switch, the output of the photodetector connected to: the first input * ADC, the output of which is connected to the first inputs of the information display device, background correction device and memory devices, and the output of the background correction device is connected to the electrical input of the photodetector, characterized in that, in order to improve performance, into the measuring device about, a reference signal switch and a comparator are introduced, and the switched inputs of the switch are connected to the output of the reference voltage generator and to the output of the comparison signal memory, and the output of the sub-, keys to the reference input of the ADC, the comparator inputs are connected to the outputs of the memory of the comparison signal and the reference generator voltages, the NAND logic cell and three D-flip-flops are introduced into the synchronization device, the installation inputs of which are connected to the output of the cycle sensor, and the synchronization inputs are connected to an ode to the clock sensor, while the direct output of the first trigger is connected to the second input of the background correction device and to the data input of the second trigger, the direct output of the second trigger is connected to the control input of the storage device of the comparison signal and to the first input of the AND-NOT logical cell, its inverse output is connected to the data input of the first trigger, the direct output of the third trigger is connected to the control input of the switch of the reference signal and the second input of the information display device, the second is the logical cell input AND NOT connected to the output of the comparator, its output is connected to the data input of the third flip-flop, and the clock cycles of the sensor output is connected to the third input of the ADC. and „1167445 1 1167445