SU1023362A2 - Device for counting ions - Google Patents

Abstract

DEVICE FOR ION ACCOUNT BY AUT.St. 474827, which means that, in order to increase the noise immunity of the device, a single vibrator is introduced into it, the third AND and the inverter, whose input is connected to the output of the time-amplitude converter, and the output to the first input the third element And, the second input of which is connected to the output of the one-shot, the start input of which is connected to the reset bus, the output of the third element And is connected to the third input of the trigger. Yu Or from f 1chE

Description

The invention relates to ranges, for measuring the concentration and spectrum of atmospheric ions. According to the main auth. About 474827,. A device for counting ions contains a ionization chamber connected to a power source and to a key connected to a control unit and to an input of an amplifier whose output is connected to an input of an amplitude-time converter whose output is connected to the inputs of two elements And, the output of the first element. And connected to the trigger input, and the output of the second element And connected to the pulse generator. The trigger output is connected to the inputs of the first and second elements AND, and the output of the second element I is connected to the counter. One of the trigger inputs is connected to the reset bus ij. A disadvantage of this device is low noise immunity / due to the fact that when there is no signal at the amplifier input after the key is closed (the ion concentration is zero), the measurement path is open for the driver to pass from the input to the output (for example, from the camera power supply through the camera, the key to the input of the amplifier and far to the pulse counter). This interference is recorded in the meter as a useful signal. This is due to the fact that the counter's input is blocked for the passage of counting pulses only by: the falling edge of the output of the amplitude-time converter, which, in the absence of a useful signal, is an interference signal. The purpose of the invention is to increase the interference. Ion counting device The goal is achieved by the fact that a device for counting ions introduces a single vibrator, a third element and an inverter, whose input is connected to an output of an amplitude-time converter, and an output to the first input of a third element, And, the second input is connected with the output of the one-shot, the start input of which is connected to the reset bus, the output of the third element I is connected to the third input of the trigger. FIG. 1 shows a block diagram of the device, the units for counting the ions of Fig.2, the schedule of operation of the individual units of the ion counting device. In FIG. 2, the following is indicated: 2a - for 9 the dependence of the signal at the output of block 4 on time 2b - the dependence of the signal on the reset bus on time, / 2s - the dependence of the signal at the output of block 5 on time, 2d - the dependence of the signal on the output of block 6 on time , 2e - dependence of the signal at the output of the block 15 on time, 2f dependence of the signal at the output of the block on time, 2q - dependence of the signal at the output of block 8 on time. The ion counting device contains an ionization chamber 1, one electrode connected to power supply 2, and the second to key 3 controlled by control unit 4. Key 3 is connected to the input of amplifier 5 loaded on amplitude-time converter b, the output of which is connected to the inputs of the two elements And 7 and 8. The output of the first element And 7 is connected to the input of the trigger 9, and the input of the second element And 8 is connected to the pulse generator 10. The output of the trigger 9 is connected to the inputs of the first and second elements And 7 and 8, and the output of the second element 8 connect to the counter 11. The reset bus 12 is connected to one of the trigger inputs, the reset bus of the counter 11 and to the trigger input of the one-vibrator 13, the output of which is connected to the input of the third element I 14, whose output is connected to the third input of the trigger 9, and the second input to the output an inverter 15, the input of which is connected to the output of an amplitude-time converter 6. The single-oscillator 13, the third element And 14 and the inverter 15 perform the function of blocking the counter 117 / The device operates as follows. When purging the test air or other gas through the ionization chamber 1 due to the electric field created by the power source 2, ions from the gas are deposited on the electrodes of the chamber 1. After the key 3 is unlocked by the control unit 4 (FIG. La) on the upper electrode of the chamber 1, ions create a charge Q CU nVte, where Q is a charge, C; c is the capacity of the chamber, F; U is the potential created by the ion, mi, c; -; n is the concentration of ions in cm of air; ; V is the volumetric air flow through the chamber, cm / s; t is the open-time time of the key 3, s; . e 1.6 K is the charge of the ion. ; When key 3 is closed at the input of amplifier 5, a pulse (Fig. 2-) of chamber 1 appears, the amplitude of which is where cxx is the input capacitance of amplifier 5. Thus, according to relation (2), all information on the concentration of ions is embedded in amplitude of the first pulse. This pulse is amplified by amplifier 5 and is fed to the input of the Amplifier of the time-converter after which the transformed pulse appears at the moment when the amplitude of the input pulse passes through a maximum (Fig. 2 (1). The pulse from the output of the amplitude-time converter goes to input elements And 7 and 8 and the inverter 16. Since before the measurement trigger 9 was given a reset (FIG. 2b), then at its output (FIG. 2) and therefore at the second inputs of the elements, And 7 is the potentiometer. Therefore, countable Impulses from generator 10 pass through the second elements 8 and are read by the counter 11 (fig.2d). Since the output of the amplitude-time converter transmits a single signal to the inverter and then inverted to the first input of the third element I, the blocking pulse from the output of the one-shot (figure 2) does not pass to the third input of the trigger 9 and does not turn it over. The trigger 9 will turn over only after the last pulse from the output of the amplitude-time converter {fig.2O. As soon as the pulse ends, the element I 8 closes and the estimator 11 stops counting, the falling edge of this pulse detects trigger 9, which blocks the inputs of the elements 7 and B.

If there is no C signal from the ionization chamber, then in this case there is no pulse from the output of the amplitude-time converter. The trigger 9 previously gave w pulse reset, therefore, on his vldsoda there is a potential that opens up ka.

cash measurement. In order to close the measurement channel, a blocking circuit is used, which for a time t selects the blocking pulse (Figure 2e), j which passes through the AND 14 element

0 to the third input of the trigger 9 and overturns it, thus closing the 1 measurement channel. After that, the interference, (the input to the amplitude-time converter does not pass.,

5 on the meter as its input is blocked. the passage of interference to the input of the counter only at the time; ) -t. Time C is selected from

condition and

H 1

l l

where 2 times the appearance of useful

momentum. This time can be made less

1 ms, and then rem kgis the whole measurement process usually takes time b C4

The advantage of the proposed device is that in the absence of a useful signal the pulse counter is blocked and any interference that can be converted as a useful signal is not recorded by the counter.

Claims (1)

(51) DEVICE FOR ION ACCOUNT by author ”474827, which entails that, in order to increase the noise immunity of the device, a single vibrator, a third element And and an inverter are inserted into it, the input of which is connected to the output of the amplitude-time converter, and the output is to the first input of the third AND element, the second input of which is connected to the output of the one-shot, the start input of which is connected to the reset bus, the output of the third AND element is connected to the third input of the trigger.