RU1830515C - Method of a determination of a delay time of a delay member - Google Patents

Abstract

The invention can be used to measure the delay time of electrical signals in various delay elements. The purpose of the invention is to increase the accuracy of measuring the delay time of a delay element. The method for determining the delay time of the delay element is to convert a pulse train with a repetition rate fex to a pulse train with a time modulation with an average frequency fk, change the frequency fBX of the pulse train, determine the frequency fBx. at which the spectral components are suppressed at frequencies fk ± m / T, where m 1, 3, 5, ...; T 1 / fk, the fax frequency is measured and the results are used to calculate the delay time using the formula Tz 1/2, with fk being less than fex by a fractional number of times. 4 ill.

Description

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The invention relates to radio measurement technology and can be used for precision measurement of nanosecond and picosecond delays of various physical elements (line segments, integrated circuits, etc.).

The aim of the invention is to increase accuracy.

In FIG. 1 shows the phase modulation functions (FIGS. 1a, c) and the corresponding spectra of modulated signals (FIGS. 1b, d); in FIG. 2 is an example implementation of a meter based on a divider with a variable division coefficient (DPCD); in FIG. 3 shows embodiments of a control unit: FIG. 4 is an example implementation of a meter based on a code store.

The delay time meter of the delay element according to the scheme of FIG. 2 comprises a pulse sequence generator 1, a divider 2 with a variable division coefficient (DLC). delay element 3, switch 4, trigger 5, spectrum analyzer 6, frequency counter 7, control unit 8. The control unit 8 according to the circuit of FIG. For contains a counter 9, and about the case of execution according to the scheme of FIG. 36 - remote control 10 and drive 11 codes.

The delay time meter of the delay element according to the circuit of FIG. 4 comprises a pulse sequence generator 12, a delay code storage 13, a single-bit statistical register 15, a switch 16, a trigger 17, a spectrum analyzer 18, a frequency counter 19, a control unit 20.

The method for determining the delay time Tk of the delay element is based on the following positions:

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{.When a sawtooth phase modulation with a period T - -1 / F is introduced into the signal with a frequency fk. 1 / fk (Fig. 1a) and its spectrum contains components at frequencies fk ± nP, where ° OH, 2.3, ... (figLb). -5

2. At half the amplitude and twice the frequency of the sawtooth phase modulation function (Fig. 1c), the components at the frequency taxfk ± mF disappear in the signal spectrum. where 1,3,5, ... (Fig. 1d) .JO

In accordance with this method, the frequency of the input pulse sequence fax is divided by R or R + 1 times depending on the current value of the control code generated in a certain way, as a result of which discrete components at frequencies fk ± nF appear in the spectrum of the output quasimander , where n is 1,2,3,4, ... (Fig. 1 b}. Some of the pulses of the irregular 20 sequence obtained in this way are passed through the delay element with a delay time T3. The control algorithm and fax frequency of the input pulses are selected t Thus, the non-uniformity of 25 pulse repetitions should be reduced by half, to the value Tz 1/2 fBX. The moment of strict equality is fixed by the disappearance of the spectral components with numbers m 1. 3, 5, ... (see, Fig. 16). 30 measure the value of f, and the delay time of the delay element is calculated using the formula T 1/2 fx.

Based on this method, several variants of measuring instruments can be implemented (Fig. 2.4).

In one of them (Fig. 2), the fractional frequency pressure is performed by a divider 2 with a variable division coefficient. The division by R or by R + 1 is carried out 40 according to the instructions of the control unit 8, in which a binary control code is generated

Ky (k) b-Qent (U / Q),

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where K is the pulse number at the output of the DPDC 2. Pressure is provided provided that the code is Ky (k) Ky (k-1). Otherwise, the input pulse train of the divider is R + 1 times. The output pulse of the DPDK 2 is input to the input of trigger 5 directly, if the code is Course) Q / 2 and through the studied delay element 3, if Ky (k) Q / 2. Such a pulse transmission mode is provided by a switch 4 controlled by a high-order code bit Ky (k), which is generated in the control unit 8.

The control unit 8 can be performed either on the basis of a counter 9 (Fig. 3a), or

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based on codes 11 (FIG. 36). In the first case, L - m, Q is the counter translation module of counter 9, the code Ky (k) corresponds to the number accumulated in counter 9 at the k-th moment in time. If the control unit 8 is implemented according to the circuit shown in FIG. 36, then the L code set from the remote control 10 can take values from 1 to Q-1. where the Q-capacity of the code accumulator 11, the code Ky (k) corresponds to the number accumulated at the k-th point in time in the code accumulator 11. In both cases (Figs. 3a, 3b), switch A is controlled by the signal from the high-order bit of counter 9 or code accumulator 11,

In the second version of the meter (Fig. 4), fractional frequency division is carried out using a code storage 13, from which an overflow signal is formed. zimander. In this case, the code Q (N / R) ± 1 is supplied to the input of the N-bit storage 13 codes, and N / R - the source is selected based on the required accuracy of the delay measurement. In a first approximation, the measurement accuracy is inversely proportional to the N / R ratio. Clocking of the drive 13 codes is carried out by a pulse sequence with a frequency fex, where L Ri; Q is the code supplied to the input of the drive 13 codes;

Ky (k) Rik-Qent (Rik / Q),

K is the number of impulse overflows of the accumulator 13 codes. The switch 16 is controlled by the high-order signal of the control code Ky (k), which is stored in a single-bit static register 15. The remaining circuit elements of FIG. 4 perform the same functions as similar elements in the circuit of FIG. 2.

The frequency of the output quasimander fk and the frequency F in the proposed method are equal

fk 0.5 fBx / (R + L / Q), F - 2 fk L / Q.

The main advantage of the proposed method for determining the delay time is its high accuracy, which is achieved by eliminating the operation of measuring the amplitudes of the spectral components of the generated signal. , ...

Claims (1)

SUMMARY OF THE INVENTION A method for determining the delay time of a delay element, which consists in converting a pulse train with a repetition rate fex into a pulse train with a time modulation with an average frequency fk, which means that in order to increase the accuracy / change pulse train frequency fBX; frequency fex is determined. at which the spectral components are suppressed at frequencies f ± t / T (where t is -1.3. 5 ....; T 1 / fk). measure the frequency fBx and use the measurement results to m1 G ™ ™ 4, l wd At yes AT lag times for form 1 leTz number of times.  fax, with fk less than fB in fraction / " b Fig. / Jk G ./ from fat w Figl