SU415604A1 - - Google Patents

Description

one

This invention relates to the field of radio electronics.

The known methods for measuring the phase angle of the steepness — the feedback coefficient of the LC oscillators — do not take into account the effect of the HIGH VOLUME harmonic components of the oscillation.

The aim of the invention is to make it possible to measure the phase angle taking into account the effect on its magnitude of the higher harmonic components of the oscillation directly in the actual operating autogenerator.

FIG. 1 is a block diagram implementing the proposed method, where:

and - and - clips of an oscillator circuit of the autogenerator;

1-investigated autogenerator;

2- communication element between the contours (in the screen);

3- additional (secondary) circuit;

4- frequency counter;

5- additional generator;

6 millivoltmeter;

Ki, К2, Кз - keys (switches).

The essence of the method is as follows.

It is known that the oscillating circuit of the autogenerator always compensates for phase shifts introduced by all elements of the self-oscillating system and disturbing factors, including higher harmonics of oscillation. The oscillations always occur at the frequency at which this compensation occurs. Therefore, the detuning of the circuit of the autogenerator relative to the generation frequency unambiguously determines the desired phase angle.

For larger detuning values (in absolute value), the influence of the secondary circuit on the frequency of the oscillator can be neglected, as the frequency approaches the frequency of the oscillator that does not have a secondary circuit - horizontal and acupuncture.

There is one point at which the secondary circuit does not reach the frequency of the oscillator. It corresponds to a strictly defined value detuning |.

This point corresponds to the value

  ,

where (fii-s is the desired phase angle of the steepness, the feedback coefficient determined with regard to all higher harmonics is oscillated. 1. Thus, the problem is reduced to determining g.

An additional circuit 3 is connected to the oscillator 1, the phase angle of which is measured by the reactive element 2, and the magnitude of the connection is chosen sufficiently small, that is, so that at the secondary (secondary) circuit 3 the frequency of generation is changed that is, there was no “delaying of the frequency, or quality-NGO, as shown in FIG. 2. Frequency meter 4 using the key / Sz can be connected either to the oscillator 1 being monitored or monitor the size of the auxiliary generator 5. The voltage on the secondary (additional) circuit is measured by a millivoltmeter 6. The key KZ allows shorting the additional (secondary) circuit, Ki short-circuits the iKOHTyp aE) togonerator. The change in the phase | Vogo angle of steepness - the feedback coefficient is made in the following sequence. 1. Use the key KZ to short the additional (secondary) circuit, connect the frequency counter to the oscillator using the key K and measure its frequency /. 2. Key L2 include a secondary circuit. The pr.i-rebuilding of this contour can be observed a curve similar to that shown in FIG. 2. The task is to find such a setting of the secondary circuit, at which the frequency of the oscillator, changing between its two extreme values, passes through the same value of /, which was determined in § 1. How should the detuning of the secondary co. The filter will then have the value |. You need to define it. . 3. Do not change the settings of the secondary source, turn off the casting of the autogauer, close the / Ci switch and, introducing distortion from the generator 5, adjust the frequency of the latter to the maximum deviation of the millivoltmeter 6. Then, switching the switch / C3 frequency 4 to the input of the generator 5, the resonant frequency of the secondary circuit fo24 is determined. Changing the frequency of the generator 5, determine the bandwidth (in two directions) 2F of the secondary circuit at the level of Zdb (half power). 5. The secondary loop quality is calculated by the formula: 6. The detuning is determined from the expression f 2 {/ - L2) Q, - - Cha /.f. J / 7. The desired angle is / person from the equation: fls - acctg. 8. Determine the result of measurement as the mathematical expectation of repeatedly measured values (fks in the –figured sequence), get the value of the desired angle with a high degree of reliability. Connecting the frequency meter 4 and the coupling element 2 with the key / to the auto oscillator under test (adds some additional impedance to the circuit of the oscillator. The reactive component of this impedance is compensated by the tuning element of the oscillator, while the active component makes some losses in the circuit of the oscillator, which is This error is small. Since all measurements are carried out by fixing relative variable voltage levels and measuring relative frequency deviations, the remaining elements of the systematic error block are not included in measurements. Inventive Method of measuring phase gradient steepness-inverse ratio connection of LC autogenerators based on the dependence of the frequency of the autogenerator on the detuning of the secondary circuit, characterized in that Phase angle measurement, taking into account the effect on its magnitude of higher harmonic components, determines the detuning of the oscillating circuit of the autogenerator relative to the frequency of its generation using the secondary circuit connected to the main circuit of the autogenerator, for which measure the frequency of generation of the autogenerator , and also the quality factor and the resonant frequency of the additional circuit, when it is detuned, relative to the frequency of the autogenerator, which provides the same value of the generated frequency as when closed. The additional contour is then determined by the known relation the phase angle sought.

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