RU2032884C1 - Integrating meter of ratio of two time intervals - Google Patents

Abstract

FIELD: measuring equipment. SUBSTANCE: meter additionally has digital control circuit, counter and connections to provide digital displaying of information. EFFECT: expanded functional capabilities. 2 cl, dwg

Description

 The invention relates to electrical radio engineering and can be used to build digital meters of the relations of time intervals.

A known time interval meter comprising a DC generator, a charging key, a DC amplifier, a storage capacitor, a discharge key and a discharge resistor, the non-earthed pole of the DC generator being connected to the middle contact of the charging key, the first contact of which is connected to the input of the DC amplifier, one the lining of the storage capacitor and one output of the discharge resistor, the second lining of the storage capacitor is connected to the output of the DC amplifier and ne of the bit key contacts, a second contact which is connected to the other terminal of discharge resistor, and the control inputs of the charge and discharge are key input device [1]
The disadvantages of the meter are low accuracy, since the output voltage contains ripple caused by the simultaneous action of the charging and discharge circuits, the lack of displaying the measurement result in digital form.

The closest to the proposed gauge relates a ratio of two slots [2] comprising a constant current generator, a capacitor, charge, discharge and extra keys, monostable multivibrator, integrator, the inverter current voltage ^_.

 The disadvantage of the prototype should include the lack of the ability to display the measurement result in digital form.

 In FIG. 1 shows a structural diagram of an integrating meter of two time intervals; in FIG. 2 voltage diagrams explaining the operation of the meter.

 The meter contains a reference voltage source 1, an integrator 2 based on an operational amplifier 3 with elements 4 and 5, a comparator 6, a differentiating chain 7, an inverting amplifier 8, electronic keys 9 and 10, RS triggers 11 and 12, elements 13-15, element OR 16, counter 17 pulses.

The output of the reference voltage source 1 is connected to the inputs of the key 9 and the amplifier 8, the output of the latter is connected to the input of the key 10. The input of the integrator 2 combines the outputs of the keys 9 and 10, and the output of the integrator 2 is connected to the input of the comparator 6, and the output of the latter through the differentiating circuit 7 is connected to the R-input of the trigger 12. The device has an input "START", combining the S-inputs of the triggers and the R-input of the counter 17, the signal inputs B _x 1 and B _x 2 connected respectively to the second inputs of the elements And 14 and 15, the outputs of which respectively connected to control inputs keys 9 and 10 and the inputs of the element OR 16, whose output is connected to the counting input of the counter 17, the overflow output N of the latter is connected to the input of the R-counter 11. Non-inverting, inverting outputs of the trigger 11 and the output of the trigger 12 are connected respectively to the first input of the element And 14, the first input of the element And 13, the output of the latter is connected to the first input of the element And 15. The output bus of the counter 17 is the output of the measuring information of the device.

 The integrating meter of two time intervals works as follows.

The input sequence _x 1 pulse of duration t ₁ is filed, and the input _x 2 duration t _2.

=

U_odt

(1) где U_инт1 выходное напряжение интегратора после воздействия импульса длительностью t₁;
R, C значения элементов интегратора.With the arrival of the "START" signal (Fig. 2), the counter 17 is reset, the triggers 11 and 12 are set to a single state (Fig. 2, U ₁₁ , U ₁₂ ), thereby allowing the passage of pulses from the input B _x 1 to the input of the counter 17. During the time interval t _{1, the} electronic switch Q is closed and the voltage V ₀ is supplied to the input of the integrator 2 from the output of the source 1. The output voltage of the integrator 2 changes according to the law
U

=

U _o dt

(1) where U _int 1 the output voltage of the integrator after exposure to a pulse of duration t ₁ ;
R, C values of the elements of the integrator.

K₁
U_инт1 К₁ ^. t₁ (2)
По мере поступления импульсов на вход счетчика 17 (фиг. 2, U₁₄) напряжение на выходе интегратора будет увеличиваться (фиг. 2, U₂) и в момент, когда счетчик 17 переполнится (т.е. после прихода n-го импульса), на R-вход триггера 11 поступит импульс, переключающий триггер 11 в нулевое состояние (фиг. 2, U₁₁). К этому времени на выходе интегратора 2 напряжение U_инт1п будет соответствовать интегральному значению длительности импульсов
U

=

U

= K₁

t₁
(3)
Переключение триггера 11 в нулевое состояние приводит к тому, что на выходе элемента И 13 вырабатывается сигнал (фиг. 2, U₁₃), разрешающий прохождение импульсов с длительностью t₂ на вход счетчика 17. На вход интегратора поступает напряжение с выхода инвертирующего усилителя 8 и напряжение на выходе интегратора 2 изменяется по закону
U

= U

U_o·K₂·dt U

- K₂t₂·K₁
(4) где К₂ коэффициент передачи инвертирующего усилителя 8.Given that U ₀ <0, we take

K ₁
U _int 1 K ₁ ^. t ₁ (2)
As pulses arrive at the input of the counter 17 (Fig. 2, U ₁₄ ), the voltage at the output of the integrator will increase (Fig. 2, U ₂ ) even when the counter 17 overflows (i.e., after the arrival of the nth pulse) , an impulse will arrive at the R-input of the trigger 11, switching the trigger 11 to the zero state (Fig. 2, U ₁₁ ). By this time, at the output of the integrator 2, the voltage U _int 1p will correspond to the integral value of the pulse duration
U

=

U

= K ₁

t ₁
(3)
Switching the trigger 11 to the zero state leads to the fact that the output of the element And 13 produces a signal (Fig. 2, U ₁₃ ), allowing the passage of pulses with a duration of t ₂ to the input of the counter 17. The input from the output of the inverting amplifier 8 and the voltage at the output of the integrator 2 varies according to the law
U

= U

U _o K ₂ dt U

- K ₂ t ₂ · K ₁
(4) where K _{2 is the} gain of the inverting amplifier 8.

- U

K₁·

t₁- K₁·K₂

t₂
(5) откуда
m

·

·n N_x (6)
Таким образом, значение N_х, регистрируемое счетчиком, будет пропорционально отношению интегральных (усредненных) значений интервалов t₁ и t₂, что позволяет проводить измерение отношения двух временных интервалов с отображением результата в цифровом виде.In the process of receipt of pulses at the input of the counter 17 (Fig. 2, U ₁₅ ), the voltage at the output of the integrator decreases (Fig. 2, U ₂ ) and at the moment when it becomes 0 (after passing pulses) (Fig. 2, U ₁₅ ), the comparator 6 switches and a short pulse appears at the output of the differentiating chain 7, switching the trigger 12 to the zero state (Fig. 2, U _в ), which leads to the prohibition of the passage of pulses to the input of the counter. By this time, the counter 17 will fix the number m, which can be determined from the equation
U

- U

K ₁

t ₁ - K ₁ · K ₂

t ₂
(5) where
m

·

N N _x (6)
Thus, the value of N _x recorded by the counter will be proportional to the ratio of the integral (averaged) values of the intervals t ₁ and t ₂ , which allows measurement of the ratio of two time intervals with the display of the result in digital form.

Claims (1)

INTEGRATING MEASURER OF THE RELATIONSHIP OF TWO TIME INTERVALS, comprising a source of reference voltage, first and second electronic keys, an integrator, first and second electronic keys, an integrator, wherein the outputs of the keys are connected to the input of the integrator, the output of the voltage source with the input of the first electronic key, characterized in that an inverting amplifier, a comparator, a differentiating circuit, first and second RS-flip-flops, first, second and third AND elements, OR elements, an impulse counter are additionally introduced, while the output of the reference voltage source through an inverting amplifier is connected to the input of the second electronic switch, the integrator output is connected through a series-connected comparator and a differentiating circuit to the R-input of the second RS-trigger, the direct and inverting outputs of the first RS-trigger, and the direct output of the second RS-trigger connected respectively with the first input of the second element And, the first and second inputs of the first element And, the output of the last with the first input of the second element And, the outputs of the second and third elements And with the inputs OR, as well as with the control inputs of the first and second electronic keys, respectively, the output of the OR element is connected to the C-input of the pulse counter, the overflow output with the R-input of the first RS-trigger control input "Start" is connected to the S-inputs of RS-triggers and R -input of the pulse counter, and the first and second signal inputs
respectively, with the second inputs of the second and third elements I.

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