SU765819A1

SU765819A1 - Logarithmic converter

Info

Publication number: SU765819A1
Application number: SU782660927A
Authority: SU
Inventors: Владимир Иванович Тимофеев
Original assignee: Центральное конструкторское бюро гидрометеорологического приборостроения
Priority date: 1978-08-21
Filing date: 1978-08-21
Publication date: 1980-09-23

Description

1one

Изобретение относитс к электроизмерительной технике и может быть использовано при построеш:и устройств дл вычислени логарифмов с представлением резу.пьтата в виде цифрового . 5 года. The invention relates to electrical measuring technology and can be used in the construction of: and devices for calculating logarithms with the representation of a result of a digital. 5 years.

Известен функциональный преобразовате .ль напр жени , содержавщй генератора эталонного напр жени , элемент сравнени , источник измер емого нап- 10 р жени ,генератор иглпульсов, триггер, элемент И, счетчик- fll, .Результат преобразовани находитс в обратной функциональной зависимости от вида функции-на выходе генератора эуалон- 15 ного напр жени ; в частном случае когда в качестве эталонного используетс генератор экспоненциального напр жени , выходной результат находитс в логарифмической зависимое- 20 ти от входного напр жени .A functional transformer is known for the voltage contained in the reference voltage generator, the reference element, the source of the measured voltage, the needle-pulse generator, the trigger, the And element, the counter-fll,. The result of the conversion is inverse functional dependence on the form of the function at the output of the generator Ewalon-15 voltage; In the particular case when the exponential voltage generator is used as the reference, the output result is in a logarithmic dependence of the input voltage.

Невысока точность преобразовани обусловлена тем, что на результат преобразовани вли ют погрешности генератора эталонного напр жени , гене- 25 ратора-импульсов, вызванные старением элементов, изменением напр жений питани , изменением температурно-влажностного режима работы преобразовател и т.д.30The low conversion accuracy is due to the fact that the result of the conversion is affected by the errors of the generator of the reference voltage, generator-pulses caused by the aging of the elements, the change in the supply voltage, the change in the temperature and humidity conditions of the converter, etc.

Наиболее близким к изобретению техническим решением вл етс логарифмический функциональный преобразователь , в состав которого вход т аналоговые переключатели, блоки сравнени , блок управлени , источники опорных напр жений, ключи, интегратор, функциональный частотный преобразователь, реверсивный счетчик, триггер знака, регистр пам ти, преобразователь коднапр жение , сумматор 2ЗЧThe closest technical solution to the invention is a logarithmic functional converter, which includes analog switches, comparison blocks, control unit, reference voltage sources, keys, integrator, functional frequency converter, reversible counter, sign trigger, memory register, converter voltage code, adder 2ZCH

Логарифмический фун1щионс1льный преобразователь работает следующим образом.The logarithmic functional converter works as follows.

. На 1 .такте - такте калибровки на вход первого блока сравнени подаетс напр жение от опорного источника , соответствующее максимсшьному значению преобразуемого напр жени , а на -вход функционального частотного преобразовател подаетс напр жение, соответствующее минимальному значению преобразуемого напр жени . По команде Пуск из блока управлени на вход интегратора через сумматор и ключ подаетс напр жение от источника опорного напр жени . С выхода интегратора напр жение поступает на входы блоков сравнени . Блоки сравнени срабатывают при равенстве напр жений на их. At step 1 - the calibration cycle, the voltage from the reference source corresponding to the maximum value of the voltage to be converted is supplied to the input of the first comparison unit, and the voltage corresponding to the minimum value of the voltage to be converted is applied to the input of the functional frequency converter. On a Start command from the control unit, the voltage from the reference voltage source is applied to the input of the integrator via the adder and the key. From the integrator output, the voltage goes to the inputs of the comparison units. Comparison blocks are triggered when the stresses on them are equal

ходах и подают соответствующие сигнаы на блок управлени . За врем , равое разности времен срабатывани блоов сравнени , на вход реверсивного четчика поступают импульсы с выхода ункционального частотного преобразоател , В реверсивном счетчике фиксиуетс число, пропорциональное погрешости , вызванной нестабильностью коэффициентов передачи функционального частотного преобразовател и интегратора , триггер знака фиксирует знак погрешности. После этого блок управлени вырабатывает команду, по которой информаци из реверсивного счетчика и триггера знака переписываетс в регистр. В результате на выходе преобразовател код-напр жение устанавливаетс напр жение, пропррциональное погрешности и соответствующее ей по знаку. На выходе сумматора устанавливаетс напр жение, равное сумме напр жений источника опорного напр жени и напр жени , пропорционального погрешности. На этом заканчиваетс такт калибровки. На втором такте (такте измерени ) на вход первого блока сравнени поступает измер емое напр жение, а на вход функционального частотного преобразовател - напр жение с выхода интегратора. По команде с.блокН управлени на вход интегратора поступает напр жение с выхода сумматора, Блоки сравнени срабатывают при равенстве напр жений на их входах и подают соответствующие сигналы на блок управлени . За врем , равное разности времен срабатывани блоков сравнени , на вход реверсивного счетчика поступают импульсы с выхода функционального частотного преобразовател , В результате в реверсивном счетчике фиксируетс число, пр мо пропорциональное значению логарифма от входного напр жени . Преимуществом данного устройства по сравнению с предыду- , цщм аналогом вл етс устранение вли ни нестабильности коэффициентов преобразовани интегратора, функционального частотного преобразовател и источника опорного напр жени на результат преобразовани . Но при этом на результат преобразовани вли ют погрешности цепи обратной св зи (преобразовател код-напр жение, сумматора напр жений), обусловленные старением комплектующих элементов, изменением напр жений питани , изменением температурно-влажностного режима работы преобразовател ит.д. Кроме того это устройство отличаетс слож ностью , так как в состав преобразовател входит большое количество аналоговых узлов - два блока сравнени , три источника опорных напр жений, функциональный частотный преобразователь , преобразователь код-напр жение/ сумматор напр жений, интегратор. Ограничены и его функциональные возможности - выходной код может быть только пр мо пропорционален значению логарифма от входного напр жени .moves and give the appropriate signals to the control unit. During the time equal to the difference between the times of operation of the comparison blocks, pulses from the output of the frequency converter are received at the input of the reversible chetcher. Thereafter, the control unit generates a command, according to which the information from the reversible counter and the sign trigger is rewritten into a register. As a result, the voltage is set at the output of the converter, the voltage is proportional to the error and the sign corresponds to it. At the output of the adder, a voltage is set equal to the sum of the voltages of the source of the reference voltage and voltage, proportional to the error. This completes the calibration cycle. In the second cycle (measurement cycle), the measured voltage is fed to the input of the first comparison unit, and the voltage from the integrator output to the input of the functional frequency converter. At the command of the control unit, the input to the integrator is supplied with a voltage from the output of the adder. Comparison units operate with equal voltages at their inputs and feed the corresponding signals to the control unit. During the time equal to the difference between the response times of the comparison units, pulses are output from the output of the functional frequency converter to the input of the reversible counter. As a result, a number directly proportional to the logarithm of the input voltage is recorded in the reversible counter. The advantage of this device in comparison with the previous analogue is to eliminate the influence of the instability of the conversion factors of the integrator, the functional frequency converter and the source of the reference voltage on the result of the conversion. But at the same time, the result of the conversion is influenced by the errors of the feedback circuit (code-voltage converter, voltage adder), due to aging of the component elements, change in supply voltage, change in the temperature-humidity mode of converter operation, etc. In addition, this device is complex, since the converter contains a large number of analog nodes — two comparison blocks, three reference voltage sources, a functional frequency converter, a code-voltage converter / a voltage adder, and an integrator. Its functionality is also limited — the output code can only be directly proportional to the value of the logarithm of the input voltage.

Целью изобретени вл етс повышение точ ности преобразовани .The aim of the invention is to improve the accuracy of the conversion.

Достигаетс это тем, что в логарифмический преобразователь, содержащий датчик входного напр жени , соединенный через закикающий контакт переключател с первым входом элемента сравнени , блок управлени , первый выход которого соединен с размыкающим входом переключател , а второй и третий выходы подключены соответственно к первым входам первого и второго элементов И, и счетчик- результата,введены делитель с посто нным коэффициентом делени ,делитель с переменным коэффициентом делени , генератор вспомогательного напр жени , генератор экспоненциашьного напр жени и генератор импульсов заполнени , счетчик RS-триггер, S-входы которого соединены со вторым и третьим выходами блока управлени , R-вход- с выходом элемента сравнени , а выход - с входом генератора экспоненциального напр жени и вторыми входами первого и второгоэлементов И, третий вход первого элемента И подключен к выходу генератора импульсов заполнени и через делитель - с посто нным коэффициентом делени , с третьим входом второго элемента И, выход которого подключен к входу счетчика, подключенному управл ющими выходами ft управл ющим входам делител с переменным коэффициентом делени и информационный вход которого соединен с выходом первого элемента И, а выход - с входом счетчика результата , причем первый выход генератора экспоненциального напр жени соединен с вторым входом элемента сравнени , .а второй выход подключен к входу генератора вспомогатель.ного напр жений, соединенного выходом с разк лкающим контактом переключател .This is achieved by the fact that in a logarithmic converter containing an input voltage sensor connected via a hinged contact of the switch to the first input of the comparison element, a control unit, the first output of which is connected to the disconnecting input of the switch, and the second and third outputs are connected respectively to the first inputs of the first and the second element And, and the counter-result, introduced a divider with a constant division factor, a divider with a variable division factor, auxiliary voltage generator, the generator an exponential voltage and a pulse generator, an RS-trigger counter, the S inputs of which are connected to the second and third outputs of the control unit, the R input with the output of the reference element, and the output with the input of the exponential voltage generator and the second inputs of the first and second elements And, the third input of the first element And is connected to the output of the generator of filling pulses and through a divider - with a constant division factor, with the third input of the second element And, the output of which is connected to the input of the counter, connected by The variable outputs of the variable-division divider control inputs, whose information input is connected to the output of the first element I, and the output to the input of the result counter, the first output of the exponential voltage generator connected to the second input of the reference element, and the second output connected to the auxiliary voltage generator input connected to the output with the breaker contact.

На чертеже приведена функциональна схема логарифмического преобразовател .The drawing shows a functional diagram of a logarithmic converter.

Claims

The proposed converter contains an input voltage sensor 1, an auxiliary voltage generator 2, a switch 3, a block, a control 4, a comparison element 5, an exponential voltage generator 6, an RS trigger 7, a filling pulse generator 8, elements. Both 9 and 10 / divider 11 with a constant division factor, divider 12 with a variable division factor, counter 13 and result counter 14. The auxiliary voltage generator 2 includes resistors P and P, divider 12 with a variable division factor t counter 15 and a group of elements And 16 ,,,., 16,. The outputs of the input voltage sensor 1 and the auxiliary voltage generator 2 are connected via a switch 3 controlled by the control unit 4 to the first input of the element compared to 5. The outputs of the control unit 4 are connected to the S-codes of the RS flip-flop 7 and the first inputs of the And 9 elements and 10. The first output of the exponential voltage generator 6 is connected to the second input of the comparison element 5, the second output is connected to the input of the auxiliary voltage generator 2. The output of the RS-trigger 7 is connected to the input of the exponential voltage generator 6 and the second inputs And 9 and 10, the R-input of the RS-flip-flop 7 is connected to the output of the comparison element 5. The output of the generator 8 of the filling pulses is connected to the third input of the element AND 9 and through the divider 11 with a constant division factor (counter) with the third input of the element And 10. The information input of the divider 12 with a variable division factor is connected to the output of the element 9, the control inputs are connected to the outputs of the counter 13, and the output is connected to the input of the result counter 14. The input of the counter 13 is connected to the output of the element 10 The converter works as follows. The conversion takes place in two cycles. On the first cycle, calibration is performed. In the initial state, the RS-flip-flop 7 is in the state O, the counters are cleared (the nullification circuits are not shown in the drawing). From the output of the generator b of the exponential voltage to the input of the generator 2 of the auxiliary voltage, a constant voltage Up flows from the output of the generator 2 of the auxiliary voltage, the voltage U and k.U are removed. . where K, and R, and R are resistors, input to the generator 2 auxiliary voltage. The control unit 4 sets the switch 3 to position II, i.e. The first input of the element 5 compares the voltage from the output of the auxiliary voltage generator 2. After that, the control unit 4 sends start-up pulses through one S-input n to RS-flip-flop 7, which is set to the state, and enable element 10. And a pulse from the output of RS-flip-flop 7 starts an exponential voltage generator b, the output of which is voltage and, arriving at the second input of the element of comparison 5, U ,, ×, e, where t is the current time; t is the time constant of the exponential voltage generator 6. At the moment of equality of the voltages IL and "o", it triggers and returns to the initial state trigger 7, which was in the state. during t t, -tIn Letting the generator 8 fill pulses through a divider 11 with a constant division factor and an AND 10 element at the counter- 13 will receive the number of pulses N N F. fin, where F is the frequency of the generator 8 filling pulses; F is the frequency at the output of divider 11 with a constant division factor; m is the division factor of the divider 11 with a constant division factor (e.g., the capacity of the counter). This calibration cycle ends, and the second cycle is the measurement. The control unit 4 sets the switch 3 to the position I, i.e. The first input of the comparison element 5 receives the measured voltage U from the output of the sensor 1 of the input voltage. Thereafter, the control unit 4 supplies a start pulse through the second S input to the RS flip-flop 7, which is set to the state, and the resolution to the element AND 9. The pulse from the RS trigger 7 output starts the exponential voltage generator 6, to vy-. during which the voltage is formed, at the time of equality of the voltage and at the inputs of the comparison element. Uo r it triggers and returns to its initial state the RS-trigger .7, which was in the state. during t 1 .. t tr-Ir, g During the time fc from the generator 8 filling pulses through the element. AND 9, the number of pulses Ч X 11. 11 will go to the input of the divider 12 with a dividing division factor; N from the output of the counter 3, and as a result, the input of the counter 4 will be received; the number of pulses Ng. t. UK O. , Uo - t; ini «o de A., The result obtained is directly proportional to the logarithm value of the input signal and does not depend on the stability of the characteristics of the exponential voltage generator 6 and the generator 8 of the filling pulses. The calibration cycle is performed both before each measurement cycle and periodically according to commands from the control unit 4. The control unit 4 can also work according to another program. 1-cycle-measurement. The first input of the element of comparison 5 receives the measured voltage, the resolution is applied to the element AND 10 in the counter 13 will be recorded the number Ny, equal to N F t-. In & B .. II cycle - calibration. The first input of the element 5 compares the voltage from the output of the auxiliary voltage generator 2, the resolution is applied to the element 9, the counters input of the divider with a variable division factor 12 receives the number of pulses NS, "i% FO -Ctni-F, In the counter 14 the number of pulses Ng, I- - NK-ceHy.b will be calculated. - In fn - –h The obtained result is inversely proportional to the logarithm of the input signal and does not depend on the instability: characteristics of the generator 6 of the exponential voltage and the generator: 8 filling pulses. The technical and economic effect of the proposed device as compared with the prototype consists, firstly, in improving the accuracy of the conversion due to the fact that the invention has resolved the errors in the prototype generation caused by the unstable characteristics of the analog nodes, namely, the voltage adder voltage converter ; Secondly, the device is simpler than the prototype, since it uses a minimum of analog nodes — one element of comparison and a generator, an exponential voltage. In addition, the functionality of the proposed device is wider, due to the possibility of obtaining the result of converting both the direct and inverse proportional values of the logarithm from the input signal. The invention includes a logarithmic converter containing an input voltage sensor, connected via a contact of the switch with the first input of the comparison element, a control unit whose first output is connected to the disconnecting input of the switch, and the second and third outputs are connected respectively to the first inputs of the first and second elements And, and a result counter, differing in that, in order to increase the accuracy of the converter, a divider with a constant division factor, a divider with. dividing effect, auxiliary voltage generator, exponential voltage generator, filling pulse generator, counter, RS trigger, the RS-trigger trigger input connected to the second and third outputs of the control unit, R-input of the short-acting trigger, to the output of the reference element, and RS-flip-flop output - with the input of the exponential voltage generator and the second inputs of the first and second elements And, the third input of the first element And is connected to the output of the pulse generator, filling and through a divider with a constant coefficient divided and - with the third input of the second element I, the output of which is connected to the counter input, connected to the control / and moves to the control inputs of the divider with a variable coefficient, the information input of which is connected to the output of the first I element and the input to the result counter the first output of the exponential voltage generator is connected to the second input of the reference element, and the second output is connected to the input of the auxiliary voltage generator connected by the output to the break contact of the switch, East chniki information received note in the examination 1. Gitis E, NA information for digital electronic converters excretory ustroystv.-M .; Energy, 1975, with. 339..

2. USSR author's certificate No. 484529, class, G O G 7/24, 1974 (prototype).