SU373637A1 - DEVICE FOR MEASURING FREQUENCY - Google Patents

Description

The invention relates to the field of measurement technology and d, -1 measurements of signals from frequency sensors can be used.

Frequency measurement devices are known, comprising a measuring unit, a controlled oscillator, a divider, closed in a ring, a reference frequency oscillator, and a circuit closed.

For the purpose of measuring measurement accuracy with an independent data acquisition in the proposed device, the output of a controlled oscillator one-way oscillator and differentiating cenochka is connected to the OR circuit, another input of which is connected to the reference frequency generator through the inhibitor circuit, and the output of the circuit OR is connected to the control inputs inhibit circuits whose control inputs are connected to the additional outputs of the triggers of the said divider.

FIG. 1 is a diagram of the proposed device for frequency measurement; in fig. 2 are diagrams showing his work.

The device for measuring the frequency contains a measuring node /, a controlled oscillator 2, a divider 3 consisting of triggers 4, a prohibition circuit 5, an odovibrator 6, a differentiating chain 7, a P1LI circuit 8, a prohibition circuit 1 1 9, and a reference frequency generator 10. Signals to the input 11 are signals of unknown frequency / d. From outputs 12, the measurement result is taken.

The operation of the device proceeds as follows.

The signal of unknown frequency enters the measuring node /, where the period of the signal is measured and converted into a control signal that controls the heater 2. From the output of the generator 2, a signal with a frequency where / (is the multiplier e0 pi, the divider 3 enters with a division factor equal to K. From the output of the divider, a signal with the frequency / d is supplied to the measuring node, where an error signal is generated and the corresponding correction is entered.

5 conversion chain. At the instants of time determined by the reference frequency generator 10, the dips are removed from the divider through prohibition schemes 5. Since the signals from generators 2 and 10 are not synchronous, it is necessary to write off

0 data from the divider in the moments of the absence of transient processes in the letters. For this purpose, with the single vibrator 6 at the time of the transient process, the impulses from the generator 10 are prohibited, and on the falling edge of the single vibrator, using a differentiating chain 7, a pulse is generated, which, through the OR 8 circuit, writes off the code from the divider. The principle of processing the received data is shown in

0 to the diagram shown in FIG. 2, where .4 -

signals at the output of the controlled oscillator, B - graph of the code increase in the divider 3, B - signal at the generator output 10. Time

2 That is chosen from the condition f ---, where n

; / max

NUMBER divider bits, / l-max - the maximum value of the measured frequency. If you need to increase Go, you can increase the number of higher-order divisor bits that are not covered by feedback. Then a code proportional to the unknown frequency will be defined by the expression Nf To-fx At moments 4; ... t t code in the divider, respectively, is yVi; L / 2; ... Nm. Therefore vV /, Vi

f .. .N, Nf ,: 2 -yVs

. L2 + .Uz,

Nf, N, + N ,.

However, if we write off the return codes from the divider, then the values of / V / can be obtained by subtracting the return code of the subsequent measurement from the return code of the previous measurement.

, ,,.

Nf ,, // 2-Лз + Лз,

i.e. jV / m.

Subject invention

A device for measuring the frequency, the measuring unit contained in it, a controlled oscillator, a divider closed in a ring, a reference frequency oscillator and a prohibition circuit, characterized in that, in order to improve the measurement accuracy in case of independent data acquisition, the output of the controlled oscillator through a single vibrator and the differentiating chain is connected to the OR circuit, the other input of which is connected via a prohibition circuit to the reference frequency generator, while the output of the P1LI circuit is connected to the controlled inputs of the prohibition circuit, the control inputs of which are connected us to additional outputs of flip-flops of said divider.

A Iv A L L I I I I I ninillllllllllllllllinilllllllllllllllll

Wi

TO

t,

Nn

N.

/

A.L.

rig 2