RU2054707C1 - Two-scaled vernier method for measuring time interval durations - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: device has generator 1 of reference frequency, input signal shaper 2, vernier scale shapers 3, 4 and 6, measuring circuits 5, 7 and 8, calculating device. EFFECT: enhanced accuracy of measurements. 2 cl, 3 dwg

Description

 The invention relates to electronic instrumentation and can be used in modern technology: radar, time interval meters, phase meters, frequency meters, digital voltmeters, etc.

There is a known vernier method of measuring time intervals using a time scale formed from the frequency of an exemplary quartz oscillator and two time nonius scales formed by vernier shock excitation generators. Vernier shock excitation generators are launched using input signals between which the time interval T _x is measured. The period of the output pulses of the generator of the reference frequency T _about differs from the periods of the output pulses of the vernier generators by a relatively small amount:
Δ T _n = T _int -T _about (1),
Δ T _k = T _vk -T _o (2), where T _{n is the} period of the output pulses of the vernier generator of the beginning of the measurement of T _x ;
T _{VK the} period of the output pulses of the vernier generator of the end of the measurement T _x .

The measured time interval T _{x is} divided into three time intervals: the segment t _xn from the first input start signal to the next pulse of the generator of the reference frequency with a duration of τ _o ; the segment T _x from this first pulse of the generator of the reference frequency τ _o to the last pulse of the generator of the reference frequency τ _o , followed by the second input table signal; segment t _xк from the last pulse of the generator of the reference frequency τ _o to the second input table signal [1]
In the known method for measuring time intervals, the time interval T _xo is determined by the method of direct counting of the pulses of the generator of the reference frequency with a period T _o and multiplying the resulting number N _o by the period of oscillations T _o . The time periods t _xn and t _{xk are} determined by the vernier method by counting the number of pulses n _vn and n _{vk of the} vernier generators until they coincide in time with the generator pulses of the reference frequency and multiplying the obtained numbers by Δ T _x and Δ T _k . The measured interval is determined by the formula:
T = t _x + _xH T _xo + t _{xk corolla} n · Δ T _n + N _o T _o +
+ n _VK · Δ T _to . (3)
The accuracy of measuring the time intervals of the vernier method is limited by the time and temperature instability of the frequencies of the vernier generators of different signs.

 The purpose of the invention is the improvement of measurement accuracy.

This goal is achieved by the fact that in the two-scale nonius method of measuring time intervals, the vernier generator of the start of counting of the measured time interval is started with the start pulse and simultaneously the pulses of the time scale of the main account τ _o are counted, and the pulses of the vernier scale of the start of the count of τ _vn are counted until the pulse coincides in time of this scale with the pulse of the main account scale τ _o , with a stop pulse, the vernier generator of the end of the account of the measured time interval is started and counting the pulses of the vernier scale of the end of the count τ _VK until the moment of coincidence in time of the pulse of this scale with the pulse of the main account scale τ _o . Before the start pulse arrives, a constant vernier scale is formed from the frequency of the reference crystal oscillator, the pulse repetition period of which T _n differs from the pulse repetition period of the main counting scale Т _о by a certain small value ΔТ in one direction or another and count the pulses of the main counting scale from the moment of coincidence the pulse time of this scale until the first pulse after the arrival of the start pulse or until the next match. After starting the vernier generator, the beginning of the counting counts the pulses of the main counting scale, starting from the second after the starting pulse and until the moment of coincidence of the pulse of this scale with the pulse of the vernier scale of the beginning of counting τ _int , and also count the pulses of the constant vernier scale τ _n , starting from the corresponding beginning counting pulses on the main counting scale and until the moment of coincidence in time of the pulse of this scale with the pulse of the vernier scale of the beginning of the counting. Then, the pulses of the vernier scale of the beginning of the count are counted until the moment of coincidence of the momentum of this scale with the pulse of the constant nonius scale, then the pulses of the main scale of the count of τ _{o are considered} from the moment of coincidence in time of the pulse of this scale with the pulse of the constant nonius scale τ _n until the first pulse after the arrival stop pulse or until the next match. After starting the vernier generator of the end of the count, the pulses of the main count scale τ _{o are} counted, starting from the second after the stop pulse and until the moment of coincidence of the momentum of this scale with the pulse of the vernier scale of the end of the count τ _ok . Next, count the pulses of the constant nonius scale τ _n , starting from the corresponding pulse count on the main counting scale after the stop pulse and until the moment of coincidence of the pulse of this scale with the pulse of the vernier scale of the end of the count τ _VK , and also count the pulses of the vernier scale of the end of the count τ _VK , until the moment of coincidence in time of the pulse of this scale with the pulse of the constant nonius scale τ _n , and then calculate the duration of the time interval T _x according to the formula.

The proposed two-scale nonius method for measuring time intervals differs from the prototype in that they form a constant nonius scale from the frequency of an exemplary crystal oscillator, the pulse repetition period of which T _n differs from the pulse repetition period of the main counting scale Т _о by a certain, arbitrarily small value ΔТ, and consider pulses of the main score scale τ _o from the moment of coincidence in time of the pulse of this scale with the pulse of the constant nonius scale τ _n until the moment of the pulse after the arrival of the start pulse. After starting the vernier generator, the beginning of the counting counts the pulses of the main account scale τ _o , starting from the second after the start pulse, and also counts the pulses of the constant vernier scale τ _n . Next consider pulses vernier scale starts counting τ _ext, then counts the pulses basic account of the scale with the point in time coincidence pulse of the scale with pulse vernier scale to the first pulse after the arrival of the stop pulse, after start vernier generator terminal count is considered the primary account scale pulses τ _o starting from the second after the stop pulse, then we count the pulses of the constant nonius scale τ _n , and also count the pulses of the vernier scale of the end of the count τ _vk .

Figure 1 presents the timing diagrams of measuring the time interval for the case of T _about <T _n <T _in ; figure 2 time diagrams of the measurement of the time interval for the case of T _about > T _n > T _in ; figure 3 is a block diagram of a device that implements the proposed method for measuring the time interval;
The device comprises a generator 1 of a reference frequency T _o for generating a main account scale with a pulse repetition period T _o for generating a constant vernier scale with a pulse repetition period T _n and for ensuring the operation of measurement circuits t _хн and t _хк , _driver of 2 input signals Т _хн start pulse and T _xk stop pulse, which is measured between the time interval T _x, shaper 3 vernier scale with pulse repetition period T _n, shaper 4 vernier scale T _ext measuring circuit 5 for measuring t _xk vremennog about the segment t _xn , the shaper 6 of the vernier scale T _VK , the measurement circuit 7 t _xk for measuring the time interval t _xk and the measurement circuit 8 and the computing device 9.

 The method of measuring the time interval is implemented as follows.

To measure the time interval t _xk are calculated pulse number n _n primary account the scale of the last coincidence pulses of the scale of duration τ _o and pulse constant vernier scale of duration τ _n before starting pulse T _xh to the first pulse τ _o after the start pulse (FIG. 1b) , counts the number of pulses N _he main account of the scale, starting with the second pulse after the start and until the coincidence pulse scale primary account and vernier scale pulse τ _ext (Fig. 1b), the number of pulses counted n _he vernier scale τ _ext (1D), counts the number of pulses N _nN vernier scale, starting with the second pulse after the start and until the coincidence pulse vernier constant τ _n and τ _ext vernier scales (1c), counts the number of pulses N _nt vernier scale (Fig.1d).

(4), где t_вн сдвиг во времени начала верньерной шкалы и начала отсчета числа импульсов N_нн по нониусной шкале;
t_нн сдвиг во времени начала отсчета числа импульсов N_нн по нониусной шкале и начала отсчета числа импульсов N_он по основной шкале.According to the time diagram in figure 1, you can make a system of equations:

(4), where t _vn is the time shift of the beginning of the vernier scale and the reference point of the number of pulses N _nn on the vernier scale;
t _nn shift in time of the beginning of the count of the number of pulses N _nn on the vernier scale and the start of the count of the number of pulses N _it on the main scale.

(5)
Работа схемы измерения t_хн устройства (фиг.3). На вход схемы постоянно поступают импульсы τ_o и τ_н, с момента их совпадения во времени счетчиком схемы начинается подсчет импульсов τ_o, с поступлением с формирователя входных сигналов стартового импульса Т_хн счет импульсов τ_o прекращается и в счетчике фиксируется число n_н. Одновременно стоповый импульс Т_хн запускает верньерный генератор формирователя нониусной шкалы Т_вн, с выхода формирователя импульсы τ_вн поступают на вход схемы измерения t_хн и подсчитываются вторым счетчиком до момента совпадения одного из этих импульсов с импульсом τ_o, и в счетчике фиксируется число n_он, а в третьем счетчике в этот момент фиксируется число N_он импульсов τ_o. Одновременно со вторым счетчиком четвертый счетчик схемы измерения t_хн подсчитывает импульсы до момента совпадения одного из этих импульсов с импульсом τ_н, и в счетчике фиксируется число n_нн. В пятом счетчике в этот момент фиксируется число N_нн импульсов τ_н, из импульсов τ_вн,τ_o и τ_н, совпавших во времени, схемой измерения t_вх формируется импульс, который поступает на вход формирователя нониусной шкалы Т_вн и срывает работу верньерного генератора. Данные со счетчиков поступают в вычислительное устройство и по заданной программе вычисляется временной отрезок t_хн.Solving the system of equations (4) we obtain:
t _hn

(5)
The operation of the measurement circuit t _xn device (figure 3). The input circuit pulses τ _o and τ constantly receives _n, since their coincidence pulse count τ _o starts time count circuit, the receipt of input signals from the driver start pulse T _xh τ _o pulse count in the counter is stopped and fixed by the number n _{of n.} Simultaneously, the stop pulse T _xh starts vernier generator shaper vernier scale T _ext, output driver pulses τ _ext fed to measuring circuit input t _xk and counted by the second counter until the coincidence of one of these pulses with pulse τ _o, and the counter is fixed number n _it and in the third counter at this moment _it is fixed number N of pulses τ _o. Simultaneously with the second counter, the fourth counter of the measuring circuit t _xn counts the pulses until one of these pulses coincides with the pulse τ _n , and the number n _nn is fixed in the counter. In the fifth counter, at this moment, the number N _{nn of} pulses τ _n is recorded, from pulses τ _vn , τ _o and τ _n coinciding in time, a pulse is generated by the measurement circuit t _in which arrives at the input of the shaper of the vernier scale T _vn and disrupts the vernier generator . Data from the counters is fed to a computing device and, according to a given program, the time interval t _{xn is} calculated.

The time interval T _x is determined by the direct counting method (Fig.1b):
T _xo = N _o T _o (6), where N _{o is the} number of pulses of the main counting scale.

The operation of the measurement circuit T _xo device (figure 3). The pulses τ _{o are} constantly fed to the input of the circuit, with the start pulse T _xn coming into the input from the input pulse shaper, the meter of the measurement circuit starts counting pulses τ _o , with the stop pulse T _xk going to the input of the stop pulse circuit, the pulse count is stopped, and the number N _o is fixed in the counter . Data from the counter goes to the computing device.

To measure the time interval t _{hk, the} number of pulses n _to the main count scale is calculated from the moment of the last coincidence of a pulse of this scale of duration τ _o and a pulse of a constant nonius scale τ _n before the stop pulse T _xk to the last pulse of the main account scale τ _o before the stop pulse T _xk ( 1b) counts the number of pulses N _approx scale main account, starting from the second pulse after the stop pulse and until coincidence of the scale and the vernier scale pulse τ _cr (1b) counts the number of pulses n _approx vernier scale τ _cr (fig.1d), counts the number of pulses N _nc vernier scale, starting with the second pulse after the stop and the time scales τ coincidence pulses _N and vernier scales τ _cr (1c), the number of pulses counted n _nc vernier scale (fig.1d).

(7) где t_вк сдвиг во времени начала верньерной шкалы и начала отсчета числа импульсов N_нк по нониусной шкале;
t_нк сдвиг во времени начала отсчета числа импульсов N_нк по нониусной шкале и начала отсчета числа N_ок по шкале основного счета.According to the time diagram in figure 1, you can make a system of equations:

(7) where t _vk is the time shift of the beginning of the vernier scale and the reference point of the number of pulses N _nk on the vernier scale;
t _nk shift in time of the start of counting the number of pulses N _nk on the vernier scale and the start of counting of the number N _ok on the main account scale.

(8)
Работа схемы измерения t_хк устройства (фиг.3). На вход схемы постоянно поступают импульсы τ_o и τ_н, с момента их совпадения во времени счетчиком схемы начинается подсчет импульсов τ_o, с поступлением с формирователя входных сигналов стопового импульса Т_хк счет импульсов τ_o прекращается и в счетчике фиксируется число n_к. Одновременно стоповый импульс Т_xк запускает верньерный генератор формирователя нониусной шкалы Т_вк. С выхода формирователя импульсы τ_вк поступают на вход схемы измерения t_хк и подсчитываются вторым счетчиком до момента совпадения одного из них с импульсом τ_o, и в счетчике фиксируется число n_ок, а в третьем счетчике в этот момент фиксируется число N_ок импульсов τ_o.Solving the system of equations (7) we obtain:
t _hk

(8)
The operation of the measurement circuit t _hk device (figure 3). The pulses τ _o and τ _n constantly arrive at the input of the circuit, from the moment of their coincidence in time the counter of the circuit starts counting pulses τ _o , with the stop pulse T _xk coming from the shaper of the input signals, the count of pulses τ _o stops and the number n _k is fixed in the counter. At the same time, the stop impulse T _xk launches the vernier generator of the shaper of the vernier scale T _VK . From the output of the shaper, the pulses τ _vk go to the input of the measurement circuit t _хк and are counted by the second counter until one of them coincides with the pulse τ _o , and the number n _ok is fixed in the counter, and the number N _{ok of} pulses τ _o is fixed in the third counter at this moment .

Simultaneously with the second counter, the fourth counter of the measurement circuit t _xk counts the pulses τ _VK until one of these pulses coincides with the pulse τ _n and the number n _nk is fixed in the counter, and in the fifth counter at this moment the number N _{nk of} pulses τ _n is fixed, from the pulses τ _vk , τ _o and τ _n coinciding in time, a pulse is generated by the measuring circuit t _xn , which is fed to the input of the shaper of the vernier scale T _vk and disrupts the work of the vernier generator.

Data from the counters is sent to a computing device and, according to a given program, the time interval t _xk and the measured time interval T _{x are} calculated.

+ N_oT_o+
+

(9)
В формулу (9) не входят величины периодов верньерных шкал Т_вн и Т_вк, чем и уменьшается погрешность изменения временного интервала Т_хдвухшкальным нониусным способом.The measured time interval T _x is determined by the formula:
T _x

+ N _o T _o +
+

(9)
The formula (9) does not include the values of the periods of the vernier scales T _vn and T _vk , which reduces the error in the change in the time interval T _{x in a} two-scale nonius method.

If the ratio of the periods of the time scales T _o > T _n > T _in (figure 2), then T _x is also determined by the formula (9).

The use of a two-scale nonius method of measuring time intervals ensures the formation of a constant nonius scale from the frequency of an exemplary crystal oscillator, which reduces the discreteness of the count Δ T T _n -T _o (Δ T = T _o -T _n ) to any small predetermined specific value and improves the measurement accuracy time intervals t _xn and t _xk , and hence the time interval T _x .

Formula (9) includes the values of the periods of the constant vernier scale T _n and the main account scale T _o , formed from the frequency F _o , which leads to a decrease in the measurement error due to temperature instability of the frequency.

Claims (2)

 1. TWO-SCALE NONIUS METHOD FOR MEASURING TIME INTERVALS, consisting in the fact that they form a constant nonius scale from the frequency of a standard crystal oscillator, the pulse repetition period of which differs from the pulse repetition period of the main counting scale by a certain small value, consider the pulses of the main counting timeline from the moment of coincidence in time of the pulse of this scale with the pulse of a constant nonius scale and until the first pulse after the arrival of the starting pulse or until the next coincidence of these pulses, simultaneously consider the pulses of the timeline of the main account from the moment the pulse of this scale coincides with the pulse of the constant nonius scale and until the first pulse after the arrival of the stop pulse or until the next coincidence of these pulses, the vernier generator of the beginning of counting of the measured time interval is started as the pulse and the pulses of the vernier scale are considered the beginning of the counting starting from the second, until the moment of coincidence in time of the pulse of this scale with the pulse of the main scale of counting, at the same time count the pulses of the main an obvious counting scale, starting from the second impulse after the start impulse arrives and until the moment of coincidence of the impulse of this scale with the impulse of the vernier scale of the beginning of counting, and also counts the pulses of a constant nonius scale, starting from the corresponding impulse reference on the main counting scale and until it coincides in time the impulse of this scale with the impulse of the vernier scale of the beginning of counting, then the pulses of the vernier scale of the beginning of counting are counted, starting from the second until the moment of coincidence in time of the impulse of this scale with the impulse constantly of the vernier scale, the vernier generator of the end of the counting of the measured time interval is started with a stop pulse and the pulses of the vernier scale of the end of the count are counted, starting from the second until the moment of coincidence of the momentum of this scale with the pulse of the main counting scale, simultaneously the pulses of the main counting scale are counted, starting from the second pulse after the arrival of a stop impulse and until the moment of coincidence in time of the impulse of this scale with the impulse of the vernier scale of the end of the count, we also consider pulses of a constant nonius scale, starting from corresponding to the beginning of the counting of pulses on the main counting scale and until the moment of coincidence of the momentum of this scale with the pulse of the vernier scale of the end of the count, then we count the pulses of the vernier scale of the end of the count, starting from the second until the moment of coincidence of the pulse of this scale with the pulse of the constant nonius scale. 2. The method according to claim 1, which consists in the fact that the measured time interval T _x is determined by the sum of the time intervals T _{x o} , t _{x n} , t _{x k} , and the duration of the time interval T _{x o is} calculated by the formula T _{x o} = NT _about , characterized in that the duration of the time interval t _{x n is} calculated by the formula

and the duration of the time interval t _{x k} - according to the formula

where T _x is the measured time interval;
T _about - the pulse repetition period of the main counting scale;
T _n - the repetition period of the pulses of a constant vernier scale;
N _{n n} - the number of pulses of the constant vernier scale of the beginning of the count;
n _n - the number of pulses of the main account scale of the beginning of the calculation of the time interval T _x ;
n _{about n} - the number of pulses of the vernier scale of the beginning of the account; N _{about n} - the number of pulses of the main account scale;
N _he is the number of pulses of the main account scale;
n _{n and} - the number of pulses of the vernier scale of the beginning of the account;
N _o - the number of pulses of the main account scale when measuring the time interval T _{x o} ;
n _{about to} - the number of pulses of the vernier scale of the end of the account;
N _{n to} - the number of pulses of the constant vernier scale of the end of the account;
n _to - the number of pulses of the scale of the main account of the end of the account of the time interval T _x ;
N _{about to} - the number of pulses of the scale of the main account of the end of the account of the time interval T _x ;
n _{n to} - the number of pulses of the vernier scale of the end of the account.

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