SU369399A1 - I ALL-UNION - Google Patents

Description

one

The invention relates to the field of radio engineering and can be used in the measurement of physical quantities with an intermediate conversion of the measured value in the time interval.

Methods are known for measuring physical quantities based on summing the measured and reference periodic values varying linearly and intermediately converting the sum of these values into a time interval.

However, the known methods have a narrow measurement range.

In order to increase the measurement range by two times, the proposed method compares the sum of the measured and reference values with a value equal to the reference one, but it is out of phase, and the measured physical quantity is determined by the difference of two adjacent time intervals, limited by the moments of equality of the compared values .

FIG. 1 shows a block diagram of a device whose operation is based on the proposed measurement method; in fig. 2 are diagrams illustrating the operation of an electrical voltage measuring device.

A device for measuring electrical voltage consists of an adder 1 to the inputs of which a measured voltage is applied

± Ux (see Fig. 2, a) and the voltage U (t) from the generator 2 of the reference voltage, which produces periodic variable voltages U (t) and lJ (t) (see Fig. 2.6), for example, triangular in shape, equal in amplitude, but out of phase. The output of the adder 1 and the second output of the generator 2 of the reference voltage are connected to the inputs of the comparison circuit 3, designed to generate single pulses at times of equal voltage ± U -} - U (t) from the adder and the voltage from the generator 2. The output of the comparison circuit ( see Fig. 2, e) is connected to the input of measurement circuit 4, designed to convert the time intervals between pulses at the output of the comparison circuit Y into a digital code, for example, by counting pulses of a reference frequency / o.

The measurement circuit 4 is controlled by the potentials E p F from the two control outputs of the generator 2 connected to the inputs of the measurement circuit 4. These potentials fix the time intervals between adjacent points of maximum amplitude of the voltage l (t) corresponding to the increase of this voltage (forward ) and decrease (reverse). When a pulse arrives from comparison circuit 3 to measurement circuit 4, at the moment when the forward stroke potential E is present at the control inputs of circuit 4, the reference frequency pulses / o are summed at the instant of the presence of potential F corresponding to the reverse stroke - pulse subtraction / o-. The device works as follows. The measured voltage ± U is summed by the adder / with the reference voltage U (t, coming from generator 2 (see, Fig. 2, d). Depending on the sign of the voltage U, the voltage and (t is shifted relative to zero level in the corresponding direction The measurement range of the Vx value lies within lt / x | 2 | / |, where Urn is the maximum value of the voltages lJ (t and T / (O, equal in amplitude. The result of the summation (t) goes to the comparison circuit 3, which is moments of equality ± Ux + U (t) t) generate single pulses. With (7g-O the time intervals between pulses ti and tz are equal Between itself, and with the sign and magnitude of the difference ti-tz, it uniquely identifies the sign and voltage value. Resetting the measurement circuit 4 to zero is performed, for example, by the leading edge of each pulse coming from the comparison circuit 3 at the time of the forward stroke, and from this pulse the counting of pulses begins. The basic relation solved by the circuit of the measuring device of Fig. 1 is as follows;

A "fo (, -.) F, | (- | - ± 2D

Have

- (- T-2DL1 g ± 4 / OD ± 4 /, X

)

2/0

x,

 2K

where K is the slope of the voltages U (t and U (t, Al is the rest of the code fixed by measurement circuit 4 before each reset pulse.

Subject invention

A method of measuring physical quantities based on summing up the measured and reference periodic values varying linearly and intermediately converting the sum of these quantities into a time interval characterized in that, in order to increase the measurement range twice, and reference values with a value equal to the reference, but it is antiphase, and the measured physical quantity is determined by the difference of two adjacent time intervals, limited by moments of equality, compare aemyh values.