SU34412A1 - Device for eliminating interference with writing radio - Google Patents

Description

Atmospheric interference, together with interference due to the internal noise of the receiving devices, is one of the main obstacles to reliable radio communications on long and short waves. Known methods of dealing with interference, based on the use of linear electrical systems of high selectivity (quartz, superheterodyne reception with a filter at a low frequency, etc.) cannot give, as theory and practice show, any complete elimination of interfering actions.

More advanced methods of combating interference are methods based on the use of nonlinear electrical systems. Known methods belonging to this category, for example, methods based on the use of an auto-vapor filter, giving a much more complete elimination of interference as compared to linear systems, all We do not allow to ensure reliable reception of radio telegraph stations in the presence of atmospheric noise.

The main disadvantage of the known methods of noise control, based on the use of an auto-parametric filter, is that, at the time the signal is applied, the signal breaks down the signal, e.

(521), ::

instead of a dash, a series of dots appear, in other words, the dash (or dots) is partially or completely destroyed by interference. Experience has shown that this major drawback is observed in various modes of the auto-parametric filter (soft. Hard, etc.) and at different amplitudes supplied to this filter.

The proposed invention has ce. Plow to eliminate this significant drawback of the auto-parametric filter. In the device for eliminating nowjex, a filter is applied in the writing radio; The traps react differently to undamped or weakly damped and strongly damped oscillations, for example, so-called autoparameter filters. According to the invention, the filters differ either in the mode of operation or in the frequency bands acting on them, one of which passes through one part of the receiving current and through the Other part, added in the receive indicator.

The drawing is a schematic diagram of the present invention. Here 2 is a device for amplifying incoming signals connected to an antenna; I, 5 and 5 linear preselection filters having either a different frequency bandwidth or

a different output frequency, or different as in the output frequency, tick and bandwidth (this is easy to achieve, using known methods of frequency conversion, for example, heterodyning); 4 and 7 - auto-parametric filters, adjusted respectively to the output frequencies of preselection filters 3 and 6 (filters 4 VI 7 can consist of several stages); 5 and -run devices, i.e., devices converting alternating voltages resulting from the output of auto-parametric filters into direct current; 9 - limiting device; 10 - I write | apparatus (relay, undulator, etc.). Suppose that the elements 6, 7 1l 8 are turned off. If, in the absence of a signal and interference, the measles of the writing apparatus (or the relay) are in position I. If there is a signal and in the absence of interference, the measles will change its position and assume position II. Experience has shown that when there is no interference in the absence of a signal, the autoparameter filter 4 is not self-excited and the measles of the writing apparatus will therefore be in position I, corresponding to the absence of a signal. In the presence of a signal and interference, the measles of the writing apparatus can occupy both position I and position II. Depending on the ratio of the amplitudes and phases between the alternating voltages caused by the signal and interference that are applied to the auto-filter filter 4, one or another position can be measured. In summary, we can make a table:

; - Thus, if the measles relay is for position II, then you can practice: H) with confidence to ascertain the presence of a signal. If, however, the relay is position I, then the presence of a signal can only be asserted with some probability PI, depending on the ratio between the signal strength and the strength of the interference. The value of PI is approximately equal to the ratio of the time during which the disturbance does not destroy the effect of the signal (i.e., the measles of the squeaking apparatus is in position II) to the total time of action of the signal. Obviously, 1-jPi will then represent the ratio of the time during which the disturbance destroys the signal to the total time the signal is acting. The MOHIHO value for brevity is referred to as the non-write probability. The smaller this value, the more confident the reception.

This probability of not writing when applying the known method of dealing with interference using an auto-parametric filter cannot be made less than a certain number for a given ratio of the power of sigal and interference. The present invention makes it possible to significantly reduce the likelihood of non-writing, i.e., it allows for more reliable reception in the presence of interference, as compared to all the reception methods known to date, it is assumed that elements 5, 4 and 5 are turned off and reason -. In this way, as was done earlier, it is easy to conclude that in this case, when the relay is in the P position, the presence of a signal can be stated with certainty; if the relay is position I, then the presence of a signal can only be asserted with a certain probability. PZ- The value 1 - RP will represent the probability of non-recording in this case.

In view of the fact that the bandwidth of the frequencies of the preselection filter 3 differs from the bandwidth of the frequencies of filter 6, the output circuits of these voltage filters will have a different curve shape. Therefore, if in the output circuit of the preselection filter 3 at some time interval: the voltage from the noise and the signal is partially or completely, due to the corresponding phase shift between them, destroyed each other, then in the starting circuit of filter 5 during the same period of time destruction, generally speaking, does not happen, et. If, in the output circuit of the preselection filter, the voltage from the signal is not compensated by the voltage from the disturbance, then the auto-steam filter 7 will self-excite and measles

The turnips will be in the position of П, e. It will be possible to ascertain the presence of a signal with almost certainty.

V. Consequently, the period of time, E of which can be ascertained with certainty

 , sishala when applying the proposed

the invention will be much more

on C; comparing with known hitherto

systems. Only in those intervals in | ee, meni, during which occurs

destruction of voltage from the signal and

interferences simultaneously in the output circuits

pre-selection filters 5 and

, it is impossible to assert the presence of a signal with certainty. I am such a destruction, the voltage from the signal and interference in both

filters at the same time — not likely. According to the present invention, the alternating voltages resulting from the output of the autoparametric filters - jpOB and 7 are rectified, the resulting direct currents add up, restrict and actuate the writing apparatus. A mathematical study of the operation of the proposed device for the elimination of interference shows that the "unwritten probability is expressed by the formula:

-,: -

 L (,) (),:

where "1. So, for example, if with the usual method of reception using an autoparameter metric filter, the interference is destroyed over the full time of the signal during the Vio, then using the described invention, noMexia will destroy the effect of the signal during

.1 p

Sh

100 ,

ten

signal action

from the total time, i.e., the invention allows to significantly reduce the information of distorted characters, i.e., it allows reliable reception of wireless telegraph stations in the presence of strong interference. . The proposed device can also be made from three pre-selection filters and three auto-parametric filters with further rectification by limiting and adding effects from the various filters to. direct current. In this case, the reliability of reception increases even more, since the percentage of distorted characters becomes insignificant.

An antenna / can be of any kind and in general it can be directed. Element 2 may consist of two or three separate elements connected respectively to two or three antennas and to two or three preselection filters. In element 2, devices for directional selection (goniometer, etc.) may be enclosed. Preselection filters can be made by any known methods.

The restriction device 9 may generally consist of one, two or three limiters connected respectively to the rectifying devices 5 and 8. The writing apparatus 10 may consist either of a relay and an undulator or of any known apparatus for recording signals. Only the use of nonlinear electrical systems allows a given position of the core, a relay (in our description this corresponds to position II) with certainty to state the presence of a signal. If only linear electric systems are used for this position, the core of the relay cannot reliably state neither the presence of a signal nor the absence of a signal, i.e. the presence and absence of a signal can only be asserted with some probability. Given the lack of reliable data on the presence of a signal in the case of linear systems, it is easy to prove that the use of linear systems does not reduce the likelihood of non-writing by methods similar to the described invention.

Therefore, in the described invention, nonlinear systems of any kind are required as a composite device, but only having the property not to react to interference in the absence of a signal, i.e., instead of auto-parametric filters 4

and 7, nonlinear systems of any kind can be taken, but possessing the indicated property.

The subject of the patent.

Claims (3)

1. Device for eliminating interference with. writing radio reception using filters / differently reacting to continuous or weakly damped and strongly damped oscillations, for example, so-called auto-steam filters, characterized in that, in order to reduce the likelihood of signal compensation by interferences, two filter systems are used that differ either - four -: mode of operation, or current; on them by frequency bands, one of the receiving systems passes through one part of the receiving current, and the other through the other part, which is then folded in the reception indicator. 2. The form of the device according to claim 1, characterized by the use of antenna / pre-selection filters 3 and 6, auto-pressure filters 4 and 7, and the pre-selection filter have different bandwidths. . 3. When the device according to claim 1, the use of filters 3 and 6 pre-selection with different frequencies.