SU847328A1 - Method of determining the ratio of two signals - Google Patents

Description

(54) METHOD FOR DETERMINING RELATIONSHIP OF TWO The invention relates to analogue technique and can be used in analog solvers, high-speed photo- and pyrometry. There is a method for determining the ratio of two signals using a controlled potentiometer. A large amplitude signal is fed to the potentiometer input, a part of which is taken from the potentiometer slider and equalized with a smaller amplitude signal. The ratio indicator is the position of the slider of the potentiometer fl. The disadvantages of this method are the need to have both signals in a similar form, as well as the low speed of calculating their ratio. In different areas of computational and measuring equipment, the relationship between the amplitudes of two signals or the ratio of the measured signal to the reference signal must be obtained at high speed .. logarithms of each of the signals followed by subtraction of the logarithms of these sz signals. The disadvantages of this method are the limited accuracy of the calculation

The signals are not signal ratios, since each of the signals is logarithmic in a separate channel, and the parameters usually do not match, as well as a limited field of use, since both signals must have the same napaMeTjw frequencies and phase, or both must be unmodulated. The purpose of the invention is to improve the accuracy of determination of attitude. To achieve the goal in the method of determining the ratio of two signals based on logarithmic signals. One of the input signals is modulated, the modulated signal is summed with the other input signal, the total signal is logarithmized and the variable component is extracted. The method is characterized by the following operations: one of the input signals is modulated with a frequency, the modulated signal is summed with the second input signal, the resulting signal is logarithmized, and the variable component is extracted. The resulting amplitude but modulated signal is a function of the ratio of the two signals. Fig, 1 is given one of the variants of the device that implements the method

Fig. 2 shows timing diagrams explaining the proposed method.

The amplitude-modulated signal and and the constant signal U are fed to the input of summing logarithmic amplifier 1, where their sum is logarithmic, i.e. the gain is the less; the larger the input signal, the deformation of the signals occurs. At the output of the amplifier, the sum of the signals of a constant (or slowly varying) and amp-modulated signal is also obtained. To find the range (i.e., double amplitude) of the modulated oscillation 2U, it is necessary from the maximum value of the total signal at the output, i.e. kl p (U + U), subtract the minimum, as shown in FIG. 2, equal to kln (UQ- and, where k is the conversion factor of the amplifier.

Thus, the amplitude amplitude component of the output signal 2 0 is 2 U – J, –k 1 n (and –C – k 1 n (U / i – i) k I n

If we denote the ratio of the signals, then the amplitude of the output signal 0 can be expressed as follows.

from kln (1 + 2 / / -i / x) F (; (/ if C «1, then, according to the decomposition in the logarithm series, U7, K, i.e. the amplitude of the output signal is proportional to the ratio of the signals.

Thus, the output amplitude modulated signal is an unambiguous function of the ratio of two signals at the input. This method is mono, for example, to estimate the ripple factor of power sources. Normally, large DC voltages are rippled due to insufficient smoothing. By applying this voltage to a logarithmic amplifier, we obtain, for example, the output of a helix, the variable component of which is separated by a capacitor, is proportional to the ripple factor.

It should be noted that it is generally possible to compare the amplitude-modulated signal not with a unipolar constant or slowly varying signal, but also with a bipolar signal. This may be required if electronic

the system has drift zero. In this case, a uni-polar signal can be easily (using, for example, a key and a capacitor, converted into rectangular pulses of variable polarity.

5 The proposed method allows

improve the accuracy of calculating the ratio of two signals by eliminating the error caused by the spread of the parameters of the two processing channels

0 signal, and expand the scope of the use of this method.

Claims (2)

1. Reference book on the technique of automatic regulation. Ed. D. Traxel, GEI, M.-L., 1962, 0 p.187. 2. Instruments and equipment of the experiment. 1976, No. 6, 0.89 (prototype). 1/1 / A BUT/ Hhll-t "I l dl l 1/1 V