SU748830A1 - Apparatus for separating the differential frequency - Google Patents

Description

(54) DEVICE FOR DIVIDING THE INVENTION The invention relates to the field of rational measurements. The device can be used to measure the frequency difference between two periodic pulsed or harmonic signals in radio engineering systems. A device is known for obtaining the frequency difference between two pulse sequences, comprising a differentiating CYL ,. two elements AND, two elements NOT and trigger 1. However, the field of application of this device is limited, since at close frequencies of the pulsed sequences, the operability depends on the order in which the pulsed sequences are fed to the inputs and on their mutual time shift. It is also known a device for isolating the frequency difference of two pulse sequences containing a number of elements common with the proposed device: input signal drivers, AND elements, trigger 2. FREQUENCIES However, with some frequency ratios of the pulse sequences being studied, and also in the region ratios, the operation of such a device is possible only with a certain order of the supply of pulse sequential sequence inputs, for example, when the ratio of the frequencies of the pulses studied by him is f 2 / 3fnB when square wave pulse is formed a lower frequency device narabotosposobno. In addition to this, when measuring the difference, the frequency of pulse sequences with similar frequency values, measurement errors may be exceeding the permissible values. Performance in terms of conditions also depends on their mutual time shift. The purpose of the invention is to expand the range of application of a device for allocating a difference frequency, With this purpose, a device containing two pulse makers and a trigger, the first input of which includes

The element I, entered adders, the element NOT and two complete pulse makers, the inputs of which are connected to the inputs of the device, and the outputs - to the inputs

one of the adders, while the inputs of the other adder are connected to the outputs of the main pulse formers, and the outputs of the adders - to one of the trigger inputs through the AND element and to the other input through the NO element,

FIG. 1 shows a functional diagram of a device for allocating a difference frequency; FIG. 2 is a time chart of his work.

Inputs 1.2 devices are connected to the inputs of the main 3.4 and additional -5.6 drivers. The outputs of the formers 3 and 4 are connected to the inputs of the adder 7 modulo two, and the outputs of the formers 5 and 6 - with the inputs of the adder 8 modulo two. The outputs of the adders 8 and 7 through the element And 9 and through the Ele; The mentor OR-NE 10 is connected to the inputs of the trigger 11, the output 12 of which is the output of the device,

The device works as follows.

When comparing two sequences of pulses in time due to the difference in their frequencies, the high frequency phase slides relative to the low frequency phase. The input pulse sequences (a and b in fig. 2) are transformed by formers 3, 4 (in figs 2 c and d cb respectively). As can be seen from the diagrams, the formers 3, 4 divide the frequency of the input pulses into two. The formers 5, 6 divide by two and shift by a quarter of the period (Fig. 2 D & e). Such an operation can be performed by inverting the input meander and further dividing by two.

The pulse sequences from the inputs of the formers 5, 6 and 3, 4 are fed to the inputs of modulators two 6 and 7, respectively. At the output of adders, periodic sequences of pulses are formed (s and g in fig. 2), the repetition periods of which are equal to the difference frequency period, the IL of the one-to-one exponency of the repetition period of the differential sequence of the pulse sequence from the output of modulators two 8 and 7 is applied to

And 9 and on the element OR-NOT 10 {element of the coincidence of the zero states). At the outputs of elements 9 and 10, groups of periodic sequences of pulses are formed, the form of which is shown in FIG. 2 and k. The distance between the beginnings of groups is equal to the period of the frequency differences. The phase shift, which occurs as a sequence of pulses from the outputs of elements 9 and 10, allows pulses from a given element of the various inputs of the trigger 11 to be extracted, the repetition frequency of which is equal to the difference frequency of the input signals.

sequences of pulses (fig, 2d).

The use in the proposed device modulo two for forming a sequence of pulses,

the repetition period of which is equal to the difference frequency of the input pulse sequences makes it possible to make the operation of the device independent of the order. input pulse input

1 and 2, Modulo two summation of the input sequences allows the device to operate at close frequencies of the input pulses.

Claims (2)

Invention Formula A device for separating the difference frequency, containing two pulse drivers and a trigger, on the first input of which an element is included, which, in order to extend the range of application of the device, adders, an element of HE and two additional pulse drivers, are introduced into it the inputs of which are connected to the inputs of the device, and the outputs - with the inputs of one of the adders, while the inputs of the other adder are connected to the outputs of the pulse formers, and the outputs of the adders - with one of the trigger inputs through the And element and the other progress through the element is NOT. Sources of information taken into account in the examination 1, USSR Author's Certificate No. 570994, Cl, H 03 K 5/00, 1976. 2. USSR author's certificate No. 369695, cl. H 03 K 5/156, 1971.