SU838603A1 - Device for measuring frequency ratio - Google Patents

Description

one

The invention relates to measurement and pulse engineering and can be used in special instrumentation for testing systems with an active response.

A device containing an integrating circuit with a threshold device and an indicator Til.

A disadvantage of the known device is that due to its low accuracy, the device performs the functions of only tolerance control and cannot be used for the purpose of measuring the actual response value.

The closest to the technical essence of the invention is a device for measuring a ratio comprising a switch, a trigger, to one input of which request signals are sent, and to the other, retreated, as well as serially connected calibration unit and measuring device 2.

However, this device is characterized by the fact that even when the response signals were sent to each of the interrogation (i.e. 100% responsive) current, the current contains a per-component - 100 μA, which introduces an additional error in the measurement, which significantly decreases accuracy) -; measure ...

The purpose of the invention is to improve the measurement accuracy of the ratio of the average frequency of the signals to the frequency of the request signals.

This goal is achieved by the fact that

0 device J containing a switch and a serially connected calibration unit, a measuring device and a main P5-trI1 -.p, two additional RS RS-triggers, two

5 OR elements and a series-connected auto generator, an AND element, a dividing unit, a Forming unit, an inverter, and an NAND element, the output of which is connected to the first input of the first

0 of the OR element, the second input of the latter is connected to the first output of the switch and the second input of the AND element, the third input of which is connected to the BU-stroke of the first additional PS-trigger 5, the first input of the last is connected to the input of the second additional C3 trigger, the output of which is connected to the second input element AND-NOT- while the second output perek.gpocha Tel connected to the first input of the second element

ORj the second input of which is connected to the output of the division unit, the outputs of the first and second elements OR are connected to the inputs of the main RS-flip-flop, and the second input of the first additional RS-flip-flop is connected to the input of the inverter.

The drawing shows a block diagram of a device for measuring the frequency ratio.

The device contains a Tipip autogenerator 1, element 2 AND block 3 dividing RS-flip-flops 4 and 5, formation block 6, elements 7 and 8 OR, inverter 9f element 10 AND-NOT, RS-flip-flop 11, switch 12, measuring device 13, block 14 calibration, bus 1-1 control, bus 16 arrival of the request signals and bus 17 arrival of response signals ,.

The device works as follows.

The device has three modes of operation (Calibration 0% Calibration 100%, Measurement).

In the Calibration 0% mode (left position of the switch 12), the control potential from the control bus 15 through the switch 12 is continuously fed to the input of element 2 AND / prohibits the passage of pulses from the generator 1, control signals at the inputs of element 7 OR and S input RS-flip-flop 4 are missing. The same control potential from the switch 12 is constantly fed to the input element, 8 OR, from its output - to R. The input of the RS flip-flop 4, is set on the left shoulder of the RS-flip-flop 4 zero potential. This state of the RS flip-flop, 4, as shown below, corresponds to the complete absence of response signals (i.e. 0% response), the arrow of the measuring device 13 is in the immediate vicinity of the zero scale of the instrument, the exact setting of the arrow to zero the mark is made by rotating the potentiometer of the calibration unit 14, thus achieving full equality of the potentials at the terminals of the measuring device 13.

In Calibration mode 100% (switch position 12) Ex. The driving potential from the bus 15 is controlled through the switch 12 continuously to the input of the element 7 OR. and from its output to the S input RS trigger 4, the unit potential is set on the left shoulder of the trigger RS 4. Such an RS-flip-flop condition 4 corresponds to the post response of the response signals to each request signal without exception (i.e. 100% responsiveness). The gauge 13 gauge is located close to the extreme right scale. device points. The exact setting of the arrow on the rightmost point of the scale is made by rotating the potentiometer of the calibration unit 14. The operation in this mode of the remaining part of the device circuit is not considered, since it does not affect the calibration process. Indeed, the periodic receipt of a control signal from the output of dividing unit 3 does not change the state of element 7 OR and RS flip-flop 4 a the periodic arrival of the control signal from the output of element 10 AND-NOT causes a change in potential only on the right shoulder of the RS flip-flop .4. Here, at the time of the control signal, a single potential is formed while at the left terminal the single potential is held continuously due to the constant presence at the S input of the control potential from the control bus 15.

In the Measurement mode (right switch position), the request signal passing through the request signal input bus 16 sets the RS flip-flop 5 and RS-flip-flop 11 to position 1. Element 2 I turns open to pass pulses of the autogenerator 1 to the input of the division unit 3. The division factor n of the division unit 3 is chosen so that the output impulse of the division unit 3 appears obviously after the last impulse of response c, kcal. The output pulse of the dividing unit 3 is fed to the input of element 7 OR, and from its output to the S input of the RS flip-flop 4, confirming that it is in position 1 or is set to this position. The output pulse of the dividing unit 3 in block 6 forms the E1 and the signal is generated, which is fed to the inverter 9 and sets the RS flip-flop 5 to the O position, closing element 2 And for passing the pulses of the auto-oscillator 1.

The passage of the pulse from the inverter 9 through the element 10 is NOT dependent on the state of the RS flip-flop 11. If a response signal is received on the transmitted request signal via the response signal bus 17, which sets the RS flip-flop 11 to the O position, the pulse input element from the inverter 3, the INE element 10 will be closed for its passage and the RS flip-flop state 4 does not change,

If the response signal is not received on the transmitted request signal, the RS-flip-flop 11 remains in the position and the output pulse of the inverter 9 passes through the elements 10 and 8 and the RS-flip-flop 4 is set to stop O.

Thus, the KAZ-trip-4 is constantly in position 1 when the response signals arrive at each of the interrogation signals and goes to position O for the time f -C at each missing response signal where fj is the duration of the output pulse of dividing unit 3. The average value of the current flowing through the measuring device 1 can be represented as) - | --- 100tAV A, (1 In expression (1), the first addendum determines the average value of the current of the micro ammeter in the absence of response signals. Flow of this current due to the periodic setting of the RS flip-flop 4 to the position O for the time ty.The second term characterizes the increase in the average value of the current due to the appearance of the response signal. Expression (l) can be written as -1 P / where f v is the frequency of the query signals) F is the frequency of response signals; t ,, is the delay time between the first impulses of the dead and the response code from which it is clear that the average current value is not proportional to the ratio F f a contains some error. (-1-PT). . The error will be maximized when and is equal to -bL ooocl / H. The mdx simplicity of the consideration of the principle of operation and the evaluation of the measurement error of the expressions (l) and (2) are given for a device in which the operation of the oscillator and the arrival of the request signals are synchronized. For the case of non-synchronous operation, the error is determined by an expression slightly different from expression (3), but the value of the maximum error does not change and is determined as in the case of synchronous operation by the expression (4}. At the frequency of the oscillator 1 MHz, Ti 0, 5 MKS, Trg1H1 250 µs mqx is gQ µA 0.2 µA, which is 0.2% in measuring the response value. Thus, in the proposed device, the measurement accuracy is significantly improved, and consequently, the reliability of the result. frequency ratio containing A yuchatel and serially connected calibration block, measuring device and main RS trigger, characterized in that, in order to improve measurement accuracy, two additional OR elements are added to the additional Rj trigger, an autogenerator, an AND element, a dividing unit, a block FSI, inverter and NAND element, the output of which is connected to the first input of the first element OR, the second input of the last is connected to the first input of the switch and to the second input of the AND element, the third input of which is connected to the output of the first additional Additional RS-flip-flop, the first input of the latter is connected to the input of the second additional RS-flip-flop | the output of which is connected to the second input of the NAND element, while the second output of the switch is connected to the first input of the second OR element, the second input of which is connected to the output of the divider, the outputs of the first and second OR elements are connected to the inputs of the main RS flip-flop, and the second input of the first additional RS-flip-flop connected to the input of the invertSources of information, rinty in BHHMatt-ie during the examination 1. Instrument KASO-U.- Technical writing and operating instructions 2. 075.008 THAT, sections 4-5, 976. 2. Technical description Isp 015020, 1976.

Claims (1)

Claim A device for measuring the ratio of a frequency-containing switch 'and a calibration unit connected in series, a measuring device and a main RS-trigger, characterized in that, in order to increase the measurement accuracy, two additional OR elements and a series-connected oscillator are inserted into it for additional RS-trigger, AND element, division unit, forming unit, inverter and AND-NOT element, the output of which is connected to the first input of the first OR element, the second input of the latter is connected to the first input of the switch and to the second input And, the third input of which is connected to the output of the first additional RS-trigger, the first input of the latter is connected to the input of the second additional RS-trigger, the output of which is connected to the second input of the NAND element, while the second output of the switch is connected to the first input of the second element OR, the second input of which is connected to the output of the division unit, the outputs of the first and second elements OR are connected to the inputs of the main RS-trigger, and the second input of the first additional RS-trigger is connected to the input of the inverter.