SU1146810A1 - Digital level gauge - Google Patents

Abstract

1. DIGITAL LEVEL METER according to aut. St. No. 361527, characterized in that, in order to increase the reliability of measurement results by eliminating errors when switching levels of the measured signal, a code setting unit is entered, the first, second, third, fourth and fifth inputs and the first and second outputs of which are connected correspondingly with the output of the second reference Logarithmic converter, with the control output of the node. sensitivity selection, with a range counter; s, with pulse, potential and additional outputs and with the first and second additional The inputs are the time of the digital converter, the third additional input of which is connected to the code of the second reference logarithm converter, and the time of the digital converter contains serially connected counting pulse generator, AND element, pulse counter and overflow trigger, serially connected decoder and searcher, as well as reset pulse generator and the rigger is not clear, while the outputs of the bits of the pulse counter are connected to the corresponding inputs of the decoder, the output of the generator L reset pulses are connected to the zero input inputs of the pulse counter and overflow and underfill triggers, the outputs of which are the pulse and potential outputs, respectively, of the digital converter time, the auxiliary output, the input and the first, second. and the third additional inputs of which are, respectively, the output of the reset pulse generator, the second input of the AND element, combined with the installation input of the unfilled trigger unit, the first and second inputs,. CO set the code of the pulse counter and the input of the pulse former reset sa. one. . - .---. : 2. The meter in accordance with claim 1, which is based on the fact that the code setting block contains the setup pulse shaper, the first and second sign change triggers, the element NOT, | i the element OR, and the first and second electors the output of the installation pulse forti liter, the input of which is the first input of the code setting unit, is connected to the first input. The first and second elements And, the second inputs and outputs of which are the third and fourth inputs and the first and second outputs respectively; the MI of the code setting unit, input and output: the element is NOT connected to the counting inputs of the first and second sign change triggers, respectively, combined the set-up inputs of which are the fifth input of the code setting block, the second input of which is

Description

The input element is NOT, and the inverse outputs of the first and second sign change trigger are connected respectively to the first and second inputs of the OR element, the output of which is connected to the third input of the second element I.

The invention relates to telecommunications and can be used in a wired communication technique for measuring signal strength.

According to the main author. St. No. 361527 5 a digital level meter is known, which contains a control amplifier, a detector, a control multivibrator, a measuring logarithmic voltage converter in a time interval, a time digital converter with a pulse counter, a sensitivity selection node with a range counter, first and second reference logarithmic converters, 5 node subtracting the time intervals and the switch of the switching signals, with the output of the control multivibrator connected simultaneously to the input of the measuring logs 20. A converter and with the inputs of the first and second reference logarithmic converters, the OUTPUTS of three logarithmic converters are connected to the corresponding inputs of the node for subtracting 25 time intervals, in addition, the output of the second reference logarithmic converter is connected to the probe input of the switching signal switch, to the pulse 30 and the potential inputs of which are connected via a time to a digital converter; the output of the time interval subtractor and the outputs of the signal switch are not eklnzcheni IJ respective inputs connected node selection chuvst pheno- ranges from counter control output dnovremenno latter is connected to the inputs of subtracting evil .vremennyh slots 40 switch the switching signals to the inputs of which forbidden podklyueny corresponding sensitivity selecting part outputs to the counter 45 i Range

The disadvantage of the known digital level meter is low

the accuracy of the measurement results due to errors caused by the process of automatic switching of the ranges of the measured signal, which makes it necessary to specifically specify in the instructions how to read the readings, otherwise it leads to significant errors. This disadvantage is especially apparent when measuring rapidly changing levels leading to frequent switching of ranges. In these cases, the reading of a digital indicator is much more difficult, the probability of reading error increases. Additional time is required to obtain reliable measurement results, which ultimately leads to a decrease in labor productivity.

The purpose of the invention is to increase the reliability of measurement results by eliminating errors when switching the ranges of levels of the measured signal.

The goal is achieved by the fact that in a digital level meter containing a controlled ampillary, a detector, a control multivibrator, a measuring logarithmic converter in the national time interval, a time digitizer with an impedance counter, a selector node with a range counter, the first and second reference logarithmic converters , the time slot subtracting unit and the switch of the switching signals, the output of the control multivibr-. the torus is connected simultaneously to the input of the measuring logarithmic converter and to the inputs of the first and second reference logarithmic converters; to the potential inputs of which is connected via time a digital converter the output of the time subtracting node The switching signal switch outputs are connected to the corresponding inputs of a sensitivity selection node with a range counter, the control output of the latter is simultaneously connected to the inputs of a time interval node and a switching signal switch, to the forbidden inputs of which the corresponding outputs of a sensitivity selection node are connected. A code setting block is entered with the range counter, the first, second, third, fourth and fifth inputs and the first and second outputs of which are connected respectively but with the output of the second reference transform transducer, with the control output of the sensitivity selection node with a range counter, with pulse, potential and additional outputs and with the first and second additional inputs the time of the digital converter, the third additional input of which is connected to the output of the second reference logarithmic converter, and the time digital converter contains a series-connected generator, counting pulses, AND element, pulse counter and overflow trigger, investigatorially connected decoder and indicator, as well as a shaper of reset pulses and an unfilled trigger; The time of the digitizer, the auxiliary output, the input and the first 1M, the second and the third additional inputs, respectively, of the pulse and potential outputs cerned are respectively reset pulse shaper output a second input of AND, associate with the input setting unit trig104 ger blank, the first and second inputs of the counter impulssov code and input of nmpulov reset. The code setting block contains the pulse shaper, the first and second character change triggers, the NO element, the OR element, and the first and second AND elements, and the output of the setting pulse generator, whose input is the first input of the code setting block, is connected to the first inputs of the first And the second elements And, the second inputs and outputs of which are the third and fourth inputs respectively and the first and second outputs of the code setting block, the input and output of the element are NOT connected to the counting inputs of the first and second, respectively sign change triggers, the combined inputs of the zero setting of which are the fifth input of the code setting block, the second input of which is the element input NOT, and the inverse outputs of the first and second sign change triggers are respectively connected to the first and second inputs of the OR element whose output is connected to the third input of the second element I. FIG. Figure 1 shows a structural electrical circuit for a predictable digital level meter; FIG. 2 shows timing diagrams explaining the principle of its operation. The digital level meter contains a controlled amplifier 1, a detector 2, a control multivibrator 3, a measuring logarithmic voltage converter 4 per time interval, a time digital converter 5 with a pulse counter, a sensitivity selection node 6 with a range counter, the first 7 and the second 8 are reference logarithmic transducers, time interval interchange node 9, switch signal switch 10 and code setting unit 11 containing setter pulse generator 12, first 13 and second 14 shift triggers sign, element 15, element OR 16 and the first and second elements 17 and 18, and the time digital converter 5 contains element 19, the generator 20 counting pulses, the counter 21 pulses, shaper 22 pulses of reset, decoder 23, indicator 24, trigger 25

overflow - and unfilled trigger 26.

The digital level meter works as follows.

The measured signal is fed to the 5th input of the digital level meter, amplified by the controlled amplifier 1, converted by the detector 2 into a constant one and fed to the input of the measuring logarithmic transducer 4, controlled by the cyclic delivering control multivibrator 3 (diagram 1, fig. 2) . The same control multivibrator 3 controls the first 7 and second 8 reference logarithmic converters.

The measuring input of the first reference logarithmic converter 7 is supplied with the reference voltage UY corresponding to the lower limit of the level range of the measured signal, and the measuring input of the second reference logarithmic converter 8 is supported by the measuring Uj of the measuring and reference 25 logarithmic converters 4, 7 l 8 respectively, output 1-pulses with a duration of 11 × x 2, m cj (Fig. 2, diagrams 2, 3, 4) are formed. The difference - D, is selected as the equivalent range of the measured signal.

The pulse duration is related to the level of the measured-signal by a logarithmic dependence, the duration is 35 ti C, and c2 is fixed, their duration is determined respectively by the reference voltages U; and U.

The pulses, 1, arrive at the corresponding inputs of the node 9 of the vail-40 time intervals, in which by logic circuits, a pulse or impulse 3 is formed, diagrams 5, 6). The formation of pulses o or, (45 is determined by the sign signal arriving at the node 9 subtracting the time intervals from the node 6 of the choice of sensitivity.

I,.

The combination of the measuring and two 50 log support transducers 4, 7, and 8 with the time interval subtracting node 9 reduces the error in the conversion of the voltage to the time interval. 55

From the output of node 9, subtraction of time intervals, depending on whether the sign signal is 1 or 0 ,. pulse - l (we denote it by t; j) is fed to the input time of the digital converter 5, in which, with the aid of element 19, this pulse is filled with high-frequency pulses of the generator 20 counting pulses. The number of counting pulses elapsed in time 7 is counted by a pulse counter 21, which is previously reset to the initial zero state by the reset pulse of the former 22. The reset pulses (FIG. 2, diagram) are formed by the former 22 when it is launched on the leading edge by the pulses of the second reference logarithm converter 8. The driver input 22 is the third additional time input of the digital converter.

After counting the number of counting pulses corresponding to the level of the measured signal, the counter 21 assumes a certain state, which is decrypted by the depiffrator 23. The signals of the decoder go to the indicator 24, which displays the digital equivalent of the measured signal.

Depending on the level of the input measured signal, there are three cases:

g, About 1.

l / l lh I - when not selected 6. JL "

   I range of levels;

0, -, - J - at the selected level range.

In the first case, the time of the digital converter 5 does not receive a pulse j, so its counter 2 pulses will be in the zero state. The zero state of the counter is determined by the zero-state decryption circuit implemented on the incomplete trigger 26, to the input of the installation O of which a reset pulse is sent to the driver 22, and to the input of the installation 1 - the signal t The output signal of the trigger 26 is the output potential signal of the digital converter time five.

In the second case, the pulse counter 21 of the time of the digital converter 5 overflows. This state of the counter is determined by the overflow trigger 25, to the counting input of which an output signal of the higher bit of the counter 21 arrives, and to the zero setting input a reset pulse of the driver 22. The output signal of the trigger 25 is the output pulse of the overflow time of the digital converter 5, .

The presence of blank and overflow output signals on the output time of the digital converter 5 indicates an unselected measuring range. The blank and overflow signals are received respectively at the potential and impulse inputs of the switch 10 of the switching signals. The same switch 10 from the sensitivity selection node 6 receives the signal of the sign, as well as sounding signals from the output of the second reference signal.

: a logarithmic converter 8. As a result of the logical interaction of the input signals of the switch 10, it generates switching signals supplied to the summing or subtracting input of the range counter of the sensitivity selection node 6. Under the action of the switching signals arriving at the summing input, the home ranges switch in the direction of decreasing. - The sensitivity of the controlled amplifier 1, and under the action of signals,

(arriving at the subtracting input, the level ranges are switched in the direction of increasing the sensitivity.

The ranges switch until the appropriate range is selected. In this case, there will be no backfill and overflow signals on the corresponding outputs of the time of the digital converter 5 and the third case mentioned will take place: Otty cj-t.

The sensitivity control occurs stepwise (sub-band) under the action of signals from the sensitivity selection node 6. These signals are also used to generate a single signal, which, in particular, can be implemented as follows.

Denote by N - the number of level ranges that are used to measure positive levels, i.e. They exceed O dB, and through M the number of ranges used in the measurement of negative levels, that is, below O dB. These ranges are counted by the node range counter o in the process of switching them. The determined status of this counter corresponds to the selected range. The number of states of the range counter of node 6 is equal to N + M ranges. All states from 1 to N are united by one logical OR circuit of node 6, and states from 1 to M by another OR circuit of node 6. The presence of a single signal at the output of the first OR circuit of node 6 indicates a positive sign of the measured level, and the presence of such a signal at the output of the second OR circuit of node 6 is about a negative sign.

If the level of the measured signal (the signal level is too small or large) is outside the measuring range of the device, then it is necessary to stop the flow of switching signals to the input of the range counter of node 6, thus fixing the state corresponding to the maximum or minimum sensitivity of the controlled amplifier 1. For This purpose is served by signals from the N-ro and M-th codes of node 6 of the choice of sensitivity.

At the end of the measurement, i.e. after the termination of pulse 3, shaper 12, a code setting pulse is formed with a certain delay (Fig. 2, diagram 8). The delay of this impulse. Ca is necessary to account for the ending

, - y ...

pulse counting processes in the counter 21, in the sensitivity selection block 6, as well as the process of forming the sign signal.

The installation pulse from the imaging unit 12 is fed to the first input of the second element I 18, to the second input of which a signal of incomplete filling arrives. If there is a resolution signal at the third input, the setup impulse from its output (Fig. 2, diagram 11) arrives. to the second auxiliary input, the time of the digital converter 5, which sets in the pulse counter of this converter such a code, in which in each decimal place is displayed after measuring with indicator 24 1Ц1фра 9. It should be noted that the signal of the resolution, the output from the element OR 16 to the third input of the second element And 18, takes place only for the cases when 9 there was no sign change (Fig. 2, diagram 10), i.e. when on the counting inputs of the first 13 and second 14 flip-flops there was no signal drop from O to 1 or from 1 to O. The first 13 and second 14 triggers at the beginning of each measurement cycle are reset with a reset pulse from the auxiliary output of the digital converter time 5 connected to the output of the driver 22. When the sign is changed (Fig. 2, diagram 12), installation of code 9 in the counter 21 is not required, since in this case the measured signal passes through the O dB point and, therefore, O dB and should to display. For this purpose, using the first trigger 13 (Fig. 2, the diagram 13O or the element 15 and the second trigger 14, as well as the element OR 16 (Fig. 2, the diagram 140 forms a prohibition signal to the third input of the second element AND 18, which eliminates the appearance at its output (Fig. 2–10, diagram 15) of the impulse of installation of the code, and hence the installation of code 9 in the counter of impulses 21. The impulse of installation of the code from the former 12 also goes to the second input of the first element 17 its second input of the overflow enable signal at its output (Fig. 2, dia frame 9) a code setting pulse appears, the first auxiliary input is the time of the digitizer 5 and the code in its counter 21 is such a code that is recorded in this counter at the time of the overflow signal, this code is de-encrypted, and the indicator 24 corresponds to this code number. The technical and economic efficiency of a digital level meter is to eliminate the error in reading the digital indicators, and thereby in reducing the reliability of the results from Eren.

Claims (2)

1. DIGITAL LEVEL METER by ed. St. No. 361527, due to the fact that, in order to increase the reliability of measurement results by eliminating errors when switching the ranges of levels of the measured signal, a code setting unit, first, second, third, fourth and the fifth inputs and the first and second outputs of which are connected respectively to the output of the second reference Logarithmic converter, with the control output of the node. sensitivity selection, with a range counter, with pulse, potential and additional outputs and with the first and second additional inputs of a time-digital converter, the third additional input of which is connected to the output of the second reference logarithmic converter, and the time-digital converter contains serially connected counting pulse generator, element And, pulse counter and overflow trigger, decryptor and indicator connected in series, reset pulse generator and non-fill trigger, while the outputs of the discharge count ^! the pulses are connected to the corresponding inputs of the decoder, the output • of the reset pulse generator ^is connected to the inputs of the zero setting ^- pulse counter and overflow and non ^- fill triggers, the outputs of which are respectively the pulse and potential outputs of the time-digital converter, additional output, input and the first, second and third additional the inputs of which are respectively the output of the reset pulse generator, the second input of the AND element, combined with the installation input of the trigger unit complements, first and second inputs .. setting the code of the pulse counter and the input of the reset pulse generator. 1 . - - \ ..... 2. The meter according to claim 1, characterized in that the code installation unit comprises an installation pulse generator, first and second sign triggers, an element NOT, an OR element, and first and second AND elements, the output of the installation pulse generator being the first the input of the code installation block is connected to the first input. I will give the first and second elements AND, the second inputs and outputs of which are respectively the third and fourth inputs and the first and second outputs of the code setting unit, the input and output of the element are NOT connected to the counting inputs of the first and second sign-change triggers, respectively, whose combined zero-setting inputs are the fifth input of the code installation block, the second input of which is SU. „I 146810 the input of the element is NOT, and the inverse outputs of the first and second triggers of the sign change are connected respectively to the first and second inputs of the OR element, the output of which is connected to the third input of the second element AND