SU991326A1 - Phase difference measuring method - Google Patents

Description

(54) the method of measuring the difference of phases

 . one

The invention relates to radar transmitters and, in particular, can be used in instrument engineering for measuring phase differences.

There is a known method for measuring the phase difference between two compared F1 sigials, according to which two quadrature signals G are formed from the compared signals. The disadvantage of it is low accuracy.

The closest technical solution to this invention is a method for measuring the phase difference, consisting in that of the compared signals form two voltages proportional to the product of the amplitudes of the compared signals and, accordingly, the sine and cosine phase differences that form the first pair of voltages, and also, the form of a third voltage, proportional to the tangent or cotangent of the phase difference over which the phase difference 2 3 is measured.

The disadvantages of this method are the non-linearity of the scale and the large measurements.

Ifehb invention - improving linearity and measurement accuracy ..

The goal is achieved. According to the method of measuring the phase difference, which consists in

Do not form the first and second voltages, proportional to the product of amplitudes and, respectively, the sine and cosine phase differences of the compared signals, and the third voltage, proportional to the tangent or cotangent of the phase difference, form a fourth voltage that is proportional to the product of amplitudes compared to 1 × 1 signals, which the normal voltage will have, which is proportional to the product of amplitudes compared to 1 × 1 signals, which the normal voltage will have, which is proportional to the product of amplitudes compared to 1 × 1 signals, which the normal voltage will have, which is proportional to the product of amplitudes compared to 1 × 1 signals that the normal voltage has, which is proportional to the product of amplitudes compared to 1 × 9 signals that the normal voltage has, which is proportional to the product of amplitudes compared to 1 × 1 signals that the normal voltage has, which is equal to 1 × signals that the normal voltage has. either the second voltage obtained by the fifth voltage

5 5 is coded and summed with the third voltage, and the resulting voltage is taken as the phase difference.

In addition, the reinforcement of the first voltage is varied according to the law of Mqr - yy p i

where NO is the gain, H is the phase difference.

The drawing shows a structural diagram of a phase meter that implements the proposed method.

Claims (2)

The circuit contains a phase detector (PD) 1, normalizing blocks 2 and 3, comparing element 4, divider 5, amplifier 6, accumulator 7 and indicator 8. Phase meter inputs are PD 1 inputs. Two compared signals of the same frequency, the phase difference between which is necessary measure, fed to the input of the phase meter. After they are detected, at the outputs of 1d, two voltages are allocated, proportional to the product of amplitudes, Ej, of the comparison signals and, accordingly, the sine and cosine of the phase difference H, i.e. and,) PCh, (J CB co34, (1; and (2) which form the first pair of voltages. In formulas (1) and (2) C is the coefficient of proportionality. Form the third voltage h or tf, ( , b) as well as the fourth voltage, E2. The first pair, voltages (1) and (2) are normalized by voltage () to normalized devices 2 and 3. At their outputs, a second pair of voltages is obtained: U5 sinf and U cps Part (5) and (6) It is known that the very high linearity of the dependences (3) has an ITO in the region of their intersection points of the phase difference axis. This property is used in measurements: the voltage (Over) is used to indicate the difference These phases are on the 2K-90 scale sections, and the voltage (3B) is on the following sections (2K + 1) 90 ° 145 °, (KO, 1, 2, ...). Included in the formula (3) the trigonometric functions vary in the same range. Taking into account the signs of stresses (1), (2) or (5), (b) allows to measure the phase difference between 6-360. The voltage (3) is formed from the first (1), (2) or second {5), (b) pairs of charges. For this purpose, the pairs of one pair are compared between, by themselves and in a predetermined ratio, exceeding one, vy, the lower voltage of the first pair, which used as a dividend, and another voltage of the same pair - as a divider. Moreover, the corresponding voltage of the second pair is also considered selected. The choice of mena1) its voltage in advance of a given inequality corresponds to the expansion of the measurement, for example, by 5-10, which ensures a decrease in the number of operations on voltages and eliminates information loss. The choice of a smaller voltage can also be performed on the third voltage (3 For this they form the reference voltage, compare the voltage (3) with it and, in advance of their specified ratio, choose a lower voltage of the first pair. The corresponding voltage of the second pair is considered to be selected. element 4 to the input of amplifier 6, as well as to the input of the Divisible, and the second voltage to the input of divider divider 5. It carries out the operation of dividing the voltages and at its output receive the voltage of the private (3). adder 7, to the second input of which the amplified N times the voltage | U-, Nsin4 or U Ncos4 (7a, b) comes from the amplifier B. After summation, the voltage is obtained,.: The relationship between the measured phase difference and the voltage (8 ) linear with a high degree of accuracy. Therefore, the voltage (8) is taken as the phase difference and is used for its indication in the indicator 8. Two main measurement modes are possible. 1. The gain coefficient before measurements is fixed and not changed during the measurement. With, 6 non-linearity, the scales at the points corresponding to the values of the phase difference U, 45 ° and 50, respectively, are 0.08%, 0.39% and 1.33%, which gives a linear gain in comparison with the known method of 13 , 5, 69.8 and 28.43 times, and, consequently, provides an increase in the accuracy of measurements. At the same time, the sensitivity is increased by N + 1 times on the whole scale. 2. The amplification factor in the measurement process varies depending on the value of the phase difference in accordance with the condition No (4-tg4) / (sin4-4), which ensures full linearity of the characteristic, expansion to at least 189 ° and a significant increase accuracy. To provide a scale size of 145 ° and 189 °, it is necessary to vary the gain factor between 2-3 and 2-100, respectively. The substantial expansion of the school allows for easier processing of stresses and an indication of the phase difference. The simplicity of the circuit implementation of the method leads to a significant economic effect. Claim 1. A method of measuring the phase difference, which consists in forming the first and second voltage proportional to the product of amplitudes and correspondingly the sine and cosine phase separation of the compared signals, and the third voltage proportional to the tangent or cotangent of the phase difference, differing from that, in order to increase linearity and accuracy, they form a fourth voltage proportional to the product of the amplitudes of the compared signals, which normalize the first or second voltage obtained by the fifth voltage amplified and summed with the third voltage and the resultant voltage is taken as a phase difference. 2. Method POP.1, characterized in that the gain This voltage is changed by law. N .JlllS, . in 7Gpcb where f is the phase difference, N0 is the gain. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 659985, cl. G 01 R 25/00, 1979. 2. USSR author's certificate number 176614, cl. G 01 R 25/00, 1965.