DEP0023572DA - Device for scanning a room - Google Patents

Description

The invention relates to a device for scanning a room and in particular for determining the location in space of an emitted sign reflecting object, for example an aircraft.

It is desirable for many purposes to scan a predetermined space with an emitted character beam. Arrangements suitable for this purpose have already been proposed in which an antenna system radiating a sharply concentrated symbol beam is moved by mechanical means in such a way that the beam scans the desired space. The disadvantages and the limited application possibilities of such arrangements are so obvious that they do not need to be explained in more detail. It is only briefly pointed out that a considerable amount of force is required to move the antenna system and that the scanning speed is necessarily quite slow.

A purely electrical scanning device has already been proposed, in which a predetermined section of space is scanned by means of a number of spaced antennas, which respectively via delay networks assigned to them individually. Phase shifters are fed from a common carrier symbol source. The invention represents a perfecting and expansion of such a device.

The device according to the invention is used for the sending or receiving side scanning of a room by means of a fixed antenna group, in which the antennas are arranged in rows with spacings between the rows and between the antennas in each row. Each antenna is connected to a character channel and each character channel is fed with characters of constant frequency. Furthermore, the symbols applied to the different channels have different frequencies which are proportional to the antenna spacing from one end of each antenna row to the other

Increase at the end of the row, so that the alternating mutual phase limitations result in a continuous rotation of the directional characteristic of the antenna system.

According to one embodiment of the invention, the characters can be fed to the antennas themselves via the character channels and in this way broadcast in the form of a beam scanning a predetermined space segment.

According to another embodiment of the invention, the characters in the character channels can be used to modulate a character received by the antennas and in this way a directional characteristic of the receiving arrangement that changes in the sense of a periodic scanning movement can be achieved.

According to a third embodiment of the invention, the characters can be fed to the antennas themselves via the character channels and broadcast in the form of a scanning beam and can simultaneously be used in a different group of character channels connected to the same or different antennas to modulate those reflected by an object located in the scanned space Signs are used to determine the location of this item.

The invention is explained in more detail with reference to the exemplary embodiments shown in the drawing. In the drawing, FIG. 1 is a schematic representation of a device according to the invention emitting a scanning beam, FIGS. 1A, 5, 7, 9 and 11 show various transmission antenna arrangements and FIGS. 2, 3, 4, 6, 8, 10 , 12 and 13 are the mode of operation

Diagrams explaining antenna arrangements, FIGS. 14, 15 and 16 show further embodiments of the invention that work with a scanning beam, FIG. 17 is a schematic representation of a receiving device according to the invention with directional characteristics that are variable in the sense of a scanning movement, FIG. 18 shows the antenna arrangement of the device 17, FIGS. 19-21 are schematic representations of other embodiments of the receiving device according to the invention, FIG. 22 is the schematic representation of a combined transmitting and receiving device according to the invention, FIG. 23 shows the antenna arrangement of the device according to FIG. 22, FIGS. <Illegible>, 24 and 25 show other embodiments of the combined transmitting and receiving device according to the invention, and FIG. 26 is a diagram for explaining the mode of operation of the device according to FIG. 25.

The transmitting device shown in Fig. 1 for scanning a predetermined space section by means of a scanning beam can be used in connection with a device of the usual type suitable for determining the location of an emitted character. The transmitting device comprises an antenna system 10, which consists of a number of antennas 11-15 arranged at a distance, which can be vertical dipole antennas, for example. In addition, the device comprises units 5-9 connected to the antennas, each consisting of a character channel for characters of different frequencies and a generator for generating characters whose frequency increases in accordance with the distance of the individual antennas from a common reference point where the signs in a given eye look all have the same phase. Each generator can for example consist of a crystal-controlled vibration generator and one or more amplifier stages. The antennas 11-15 are advantageously arranged at equal intervals from one another, for example at intervals of half a wavelength of the character supplied to the central antenna 13. In this case, the frequencies of any signs applied to adjacent antennas differ and are of the same magnitude, and the total radiation from the antennas is in the form of a sharply concentrated beam.

The mode of operation of the device according to the invention can best be illustrated by a mathematical analysis. In the course of the following analysis, which essentially relates to the arrangement according to FIG. 1, considerations relating to other embodiments of the device according to the invention are also made in order to make the invention more understandable. For the purposes of this analysis, the antennas 11-15 are considered to be ideal point radiators. This theoretical assumption has the advantage that the directional characteristic of the antenna system is then the same in all planes which the straight line connecting the individual antennas to one another contains. The usual antennas actually have directional characteristics that depend on their shape, such as the toroidal characteristic of the vertical dipole antenna. If one were to base the theoretical analysis on such dipole antennas, this would have the disadvantage that the directional characteristic of the antenna system 10 shown in the drawing would be influenced by the individual characteristics of the antennas and would consequently be different in different planes.

First of all, certain basic properties of the antenna system 10 are to be examined. It is assumed that the antennas 11-15 are excited by a common carrier wave symbol in the same phase. The antenna system then has a directional characteristic whose section with a plane containing the straight line connecting the antennas has the shape of a sharply concentric beam. The direction of this beam depends on the mutual spacing of the antennas and on the phase relationship of the characters fed to them. For a given mutual spacing of the antennas, the direction of this beam can be changed by simultaneously changing the phase relationship between each pair of antennas in the antenna system. According to the invention, the scanning of a predetermined section of space with a beam is effected by continuously changing the phase relationship between the characters emitted by adjacent antennas. As can be seen from the following analysis, this can be achieved by feeding characters of different frequencies to the neighboring antennas. The term "phase relationship" is used arbitrarily here with reference to vibrations of different frequencies to denote the difference in phase angle at any given instant. This difference is of course constantly changing and in the sense of the designation used here is zero when both oscillations intersect the zero axis at the same point in time when they transition from negative to positive values.

If the phase relationship between the symbols of adjacent antennas changes linearly with time, the change in beam direction is with respect to time according to a sine curve. If, on the other hand, the aforementioned phase relationship changes according to a sinusoidal curve, the change in the direction of the beam takes place at a constant angular velocity. Scanning with a beam that changes its direction at a sinusoidal speed is very advantageous with regard to the design and operation of the vibration generators feeding the antennas and is therefore used as the basis for the following investigations.

Initially only two antennas of the antenna system are considered and it is assumed that the excitation of the two antennas is given by the following equations:

e (sub) 0 = E (sub) 0 cos (omega) (sub) ct (1)

e (sub) 1 = E (sub) 1 cos (Omega) (Sub) ct + (Phi) (2)

In these equations means

e (sub) 0 = the instantaneous value of the character voltage supplied to one antenna

E (sub) 0 = the peak signal voltage applied to the same antenna

(Omega) (sub) c = the angular frequency 2 (Pi) f, in which f is the frequency of the signal voltage applied to the antennas,

t = the time

e (sub) 1 = the instantaneous value of the character voltage supplied to the other antenna,

E (sub) 1 = the peak value of the symbol voltage applied to this other antenna, it being initially assumed that this voltage is the has the same frequency as the symbol voltage applied to the first-mentioned antenna, and

(Phi) = the instantaneous phase difference between the character voltages fed to the two antennas.

The directional characteristic of this pair of antennas is in the form of a sharply concentrated beam, which changes its direction according to the change in the phase angle (Phi). By changing the phase angle linearly with time, the beam can be made to scan at a sinusoidal speed. The phase angle changes according to the equation:

(Phi) = 2 (Pi) f (sub) ht (3)

which can also be written in the following form:

(Phi) = (Omega) (sub) ht (4)

In these equations means

f (sub) h = the frequency of the change in phase angle (Phi), and

(Omega) (sub) h = the angular frequency 2 (Pi) f (sub) h.

From equations (2) and (4) it follows that the character emitted by the second antenna can also be expressed by the following equation:

e (sub) 1 = E (sub) 1 (omega) (sub) c + (omega) (sub) h) t (5)

From this equation it becomes clear that a linear change in the phase angle (Phi) can be achieved simply by supplying the second antenna of the antenna pair with a symbol whose frequency is higher than that of the first

Antenna supplied character. This pair of antennas can of course be any desired pair of adjacent antennas of the antenna system 10. Therefore, in the case of a number of antennas equally spaced in a straight line, a sinusoidal velocity scanning of the beam is achieved by supplying symbols of different frequencies to the individual antennas, the frequency difference between the adjacent antennas being constant. The sampling frequency is equal to the difference frequency f (sub) h. The greater this difference frequency, the faster the scanning takes place.

The shape of the directional characteristic of the device representing the scanning beam depends both on the antenna spacings and on the frequency spacings of the symbols. For the purpose of examining the relevant relationships, the antenna system alone is shown in FIG. 1A. If one looks at a pair of neighboring antennas, e.g. antennas 13 and 14, and assumes that these antennas are excited by symbols of the same frequency but with a phase difference (Phi), then this is obtained from antenna 13 at a distant point P Sign to:

e '(sub) 13 = E' (sub) 13cos (Omega) (sub) ct (6)

wherein

E '(sub) 13 = the peak value of the symbol voltage received by antenna 13 at point P.

The symbol received by the antenna 14 at the same point P differs from the symbol received by the antenna 13 by two phase components, one of which is based on the phase difference (Phi) between the antennas 13 and 14

Characters and the other is due to the mutual spatial spacing of the antennas. If it is initially assumed that the symbol fed to the antenna 14 has the same frequency as the symbol fed to the antenna 13, then the symbol received by the antenna 14 at the distant point P results in:

e '(sub) 14 = E' (sub) 14 cos (Omega) (sub) ct + (Phi) + <formula> (7)

wherein

E '(sub) 14 = the peak value of the character received at point P by antenna 14,

(Alpha) = the angle between the direction of point P and the straight line connecting the antennas,

d = the mutual spacing of antennas 13 and 14 in any units

(Lambda) = the wavelength of the antennas 13 and 14, expressed in the same units, means character vibrations supplied.

If you put <formula> in this equation, the equation has the following form:

e '(sub) 14 = E' (sub) 14 cos (Omega) (sub) ct + 2 (Pi) a cos (Alpha) (8)

According to the invention, the phase difference (Phi) between the characters fed to the antennas 13 and 14 should change linearly with time so that the beam executes an angular scanning movement. This is achieved in that a carrier wave is fed to the antenna 14, the frequency of which is different from that of the carrier wave fed to the antenna 13.

In this case (Phi) = (Omega) (sub) ht and equation (8) takes the form: (9)

For the preferred case that the antennas 11-15 are arranged at the same intervals and are excited by characters whose frequencies differ by the same amount and increase in the direction from the antenna 11 to the antenna 15, the results at the distant point P from the character voltages received by antennas 15, 12 and 11 to: (10) (11) (12)

The symbol voltage received by all antennas taken together at point P is of course the algebraic sum of the symbol voltages received by the individual antennas and results from the algebraic addition of equations (6) and (9) to (12). If one assumes, for the sake of simplicity, that the characters fed to the antennas all have the same amplitude, the algebraic sum of equations (6) and (9) to (12) results after simplification as: (13)

In connection with this equation, it is important to note that the factor a expressing the antenna spacing depends only on the wavelength of the character applied to the antenna 13, i.e. on the wavelength of the character having the fundamental frequency of all the characters applied to the antennas. This ratio of the antenna spacing to the fundamental frequency is also used as a basis for the further explanations and must always be be respected in order to avoid errors.

A graphical method for solving equation (13) will now be described. This method is particularly useful to quickly and accurately determine the shape and size of the main radiation and any secondary radiation of the antenna system for any given number of antennas and for any given mutual spacing of these antennas, as well as to determine how a change in the units of wavelength The antenna spacing expressed by the oscillation of the fundamental frequency, which accordingly depends both on the space between the antennas and on the fundamental frequency, influences the main radiation and the secondary radiation. This method also clearly proves that the scanning speed only depends on the frequency difference of the characters fed to the antennas and that, on the other hand, the frequency difference in itself does not affect the shape of the directional characteristic of the antenna system in any way. Finally, the method mentioned is also suitable for uncovering the presence of any secondary radiation and providing information about the way in which it can be influenced by changes in the operating data of the device. The usability of this method is not limited to ideal point antennas; rather, the method also enables consideration of the directional characteristics of the individual antennas and of the reflector antennas used, for example, to increase the radiation in the desired direction.

FIG. 2 shows a graphical solution of equation (13) and illustrates the directional characteristic of the antenna system 10 according to FIG. 1 at three points in time during a sampling period. The graphical solution shown is based on the fact that the

Directional coefficient 2 (Pi) a cos (alpha) occurs in every term of equation (13), which contains the quantity (omega) (sub) ht. The value of equation (13) is therefore plotted over a certain range of values of the quantity (omega) (sub) ht under the condition that <formula> and the directional coefficient 2 (pi) a cos (alpha) = 0. The directional coefficient 2 (pi) a cos (alpha) is then plotted separately. After this has been done, phase increases graphically determined are added to any desired value of the quantity (Omega) (sub) ht on the directional coefficients corresponding to the various values of (Alpha). The values of equation (13) for the selected value (Omega) (sub) ht and the selected values of (Alpha) can be read off directly from the first graphical solution and are plotted against corresponding values of (Alpha) to give the shape of the Directional characteristic for the selected value of the size (Omega) (sub) ht.

The procedure is as follows. The multiplication factor of the first term of equation (13) is a voltage component of constant amplitude and therefore a horizontal line indicating this voltage component is drawn at a height E 'corresponding to the value of the term above the reference axis 0-0, as indicated by the dash-dotted line A. is shown. The multiplication factor of the second term of equation (13) is e2E´cos (omega) (sub) ht + 2 (pi) a cos (alpha). The value of this term is plotted over a range of values of (omega) (sub) ht in the manner shown by the dash-dotted curve B, it being assumed that <formula> and consequently 2 (pi) a cos (alpha) = 0 is. Similarly, the value of the multiplication factor of the third term of equation (13) is plotted over the same range 0-2 (Pi) and this gives the dashed curve C.

The sum of these terms is shown in Fig. 2 by the solid line

Curve D shown. This represents a modulated carrier wave having a carrier wave component E cos (omega) (sub) ct and modulation components expressed by the second and third terms of equation (13). The equation of the modulation envelope

e '(sub) m = E' + 2E'cos ((Omega) (sub) ht + 2 (Pi) a cos (Alpha) + 2E'cos 2 (Omega) (sub) ht + 2 (Pi) a cos (Alpha)) (13a)

shows that curve D can also be understood as half of the amplitude modulation envelope of such a carrier wave, with the negative parts of the curve appearing above the 0-0 axis. The unit level represented by curve A corresponds to the level of the unmodulated carrier wave. This means that a carrier wave modulated with a modulation symbol corresponding to curve D is overmodulated, this overmodulation occurring in those time segments in which curve D is below the 0-0 axis. Since the overmodulation reverses the polarity of the emitted character, those areas enclosed by curve D which do not represent overmodulation are designated as positive areas and those which represent overmodulation as negative areas. This designation can also be found in the directional characteristic of the device derived from curve D.

It should be noted here that in the event that equation (13) would contain further terms, each of these additional terms would also be drawn in the form of a curve in the manner described and used to determine curve D.

The manner in which the directional characteristic of the antenna system 10 is determined from curve D for any given value of (omega) (sub) ht will now be described. Assuming that the directive characteristic for the value (Omega) (sub) ht = (Pi) is to be determined, first a circle E is drawn, whose center o lies vertically above the abscissa value (Omega) (sub) ht = (Pi) and whose radius 2 ( Pi) a is. The parameter a was determined in connection with equation (8) as a function of the antenna spacing and the wavelength of the symbol containing the fundamental frequency of all symbols applied to the antennas. As a result, for the antenna system 10 in which <formula> is, the radius of the circle E becomes (Pi). A radius OP is drawn in this circle at any angle (alpha). The distance O-P 'is equal to 2 (Pi) a cos (alpha) or (Pi) cos (alpha), since the radius OP is equal to (Pi). Therefore the point P '' projected on the axis 0-0 corresponds to a phase shift (Omega) (sub) ht + 2 (Pi) a cos (Alpha) = (Pi) + (Pi) cos (Alpha). This is the value of the phase angle occurring both in the second and in the third term of equation (13). As a result, the amplitude of curve D for this phase angle represents the solution of equation (13) for the selected values of (omega) (sub) ht and (alpha). However, the equation gives the value of the total, radiated by the antenna system and am Energy received at point P. The value of the equation determined graphically from the curve D is plotted from the center O of the circle E to the radius OP and results in a point x of the directional characteristic of the antenna system. In the same way, other points of this directional characteristic can be obtained for other values of the angle (alpha) and the totality of these points gives the curve F representing the directional characteristic for (omega) (sub) ht = (Pi). The lower half of curve F is omitted in order to simplify the illustration. It is a reflection of the upper half.

In the case of <Formula>, the center 0 'of the circle E' is vertically above the value <Formula> on the abscissa axis 0-0. The curve G determined by the method described above represents the directional characteristic for this value of (Omega) (sub) ht, while the curve H obtained in the same way by means of the circle E '' represents the directional characteristic for the value (Omega) (sub) represents ht = 2 (Pi).

It can be seen from the curves F, G and H that the main beam executes a scanning movement from the antenna 15 fed with the symbol of the highest frequency towards the antenna 11 fed with the symbol of the lowest frequency. If the antennas 11-15 are viewed as ideal point antennas, the curves F, G and H, as already mentioned, represent the directional characteristic of the antenna system in each plane which contains the straight line connecting the antennas to one another. If, on the other hand, the antennas have their own directional characteristics, the named curves represent the directional characteristics of the antenna system in only one plane, for example in the horizontal plane.

If the method described above is only to be used to graphically determine the directional characteristics of an antenna system on an antenna system consisting of antennas with their own directional characteristics that are identical to each other, it is only necessary to consider the individual antennas as if they had no directional characteristics in the plane in question and then to correct the directional characteristic of the antenna system obtained in this way according to the directional coefficient of the individual antennas in this plane. FIG. 3 shows this for an antenna system according to FIG. 1 consisting of vertical dipole antennas, it being assumed that the directional characteristic in the vertical planes containing the antennas is to be determined for <Formula>. This directional characteristic would be if one of your own

Directional characteristics of the individual antennas would be seen, which have the shape shown by the curve G of FIG. As is known, the directional coefficient of a vertical dipole antenna has approximately the value cos (alpha) in the vertical plane and, as a result, these values are plotted for various sizes of the angle (alpha), curve I of FIG. 3 being obtained. The amplitude resulting for a given value of the angle (alpha) at a point on curve G in FIG. 2 is then multiplied by the directional coefficient of the individual antennas and a corresponding point of the desired directional characteristic is obtained for the same angle (alpha). The curve F of FIG. 3 resulting in this way accordingly represents the directional characteristic of the antenna system 10, which consists of vertical dipole antennas arranged along a horizontal straight line, in the vertical plane.

It was found further above that curve D in FIG. 2 represents the envelope curve of an amplitude-modulated carrier wave. If the energy radiated by all antennas of antenna system 10 were to be combined directly while maintaining their phase differences and fed to the vertical electrodes of an oscilloscope, the image of an overmodulated carrier symbol shown in FIG. 4 would be obtained on the oscilloscope screen. If one now considers the general case of an antenna system consisting of a finite number of antennas, it can be shown by mathematical derivation from equation (13) that the directional characteristic of such an antenna system with an odd number n of antennas can be shown by the following equation given is:

in which K (sub) o and K (sub) m are constants whose size depends on the amplitude (their size is one if the antennas are excited with the same amplitude),

m the number of the link in the series and

m '= <formula> is.

The amplitude of the small secondary radiation can be reduced at the expense of the maximum strength of the main radiation by exciting the individual antennas with different amplitudes. Equation (14) also remains valid in this case, provided that the pairs of adjacent antennas calculated from the central antenna are excited with the same amplitude.

In a manner similar to the derivation of equation (13), it can be shown that the directional characteristic of an antenna system consisting of six antennas excited with the same amplitude is expressed by the following equation:

From this equation the directional characteristic of an even number n of antennas can be derived in the following form: in which

K (sub) m is a constant, the value of which depends on the amplitude of the excitation of the antenna. hangs,

m is the number of the link in the series, and

m '= <formula> is.

Equation (15a) is valid both for the case of excitation of the antenna with the same amplitude and for that of its excitation with unequal amplitude, if only the pairs of adjacent antennas calculated from the center of the antenna system are excited with the same amplitude.

FIG. 5 shows an antenna system 10 'of this type consisting of antennas 16-21. The graphical solution of equation (15) for the antenna system according to FIG. 5 has the form of curve D' of FIG. 6 and curve F. ', G', H 'show one half of the directional characteristic of the antenna system 10' for the values (Pi), <Formula> and 2 (Pi) of the quantity (Omega) (sub) ht. A comparison of the curve in FIGS. 2 and 6 shows that adding an antenna to the antenna system concentrates the main radiation somewhat more sharply, but results in a smaller amount of secondary radiation.

The antenna system 10 'according to FIG. 7 differs from that according to FIG. 5 only in that a number of auxiliary antennas 22-27 are arranged a quarter wavelength behind the main antennas 16-21, these auxiliary antennas being excited with symbols which have the same frequency have, like the characters supplied to them, the corresponding main antennas, but are shifted in phase by 90 ° with respect to these. The graphical method for determining the directional characteristic of this antenna system is identical to that shown in Fig. 3, by dividing the directional characteristic resulting for any value of (Omega) (sub) ht by the directional coefficient of a pair of antennas located one behind the other, for example the antenna pair 16 and 22, is corrected.

The directional coefficient of this pair of antennas in the plane containing both antennas of this pair is given by the equation: (16)

This coefficient is shown graphically in the form of curve L in FIG. 8 and is used to derive the curves F ', G ", H" which give the complete directional characteristic of the antenna system 10 "for the values (Pi) <formula> and 2 (Pi) represent the size (Omega) (sub) ht. While the curves F ', G' and H 'of FIG. 6 each represent only one half of the directional characteristic of the antenna system according to FIG. 5, the curves F ", G" and H' show the complete directional characteristic of the antenna system according to FIG. 7. It follows from this that the auxiliary antennas 22-27 concentrate the energy emitted by the antenna system 10 ″ in one direction.

The antenna system 10 '' 'of FIG. 9 differs from that of FIG. 5 only in that the antennas 16-21 are arranged at intervals of a quarter wavelength each. If the symbols applied to the individual antennas have the same frequency as the symbols applied to the corresponding antennas of the antenna system of FIG. 5, then curve D 'of FIG. 10 corresponds to the same curve of FIG. 6 and represents the graphic solution of equation (15) for the antenna system 10 '' '. The curves F '' ', M, N and H' '' of FIG. 10 drawn with the aid of the circles R, R ', R' 'and R' '' each represent one half of the directional characteristic of the antenna system 10 '' ' the values <Formula> and 2 (Pi) of the quantity (Omega) (sub) ht.

It can be seen from these curves that a reduction in the mutual spacing of the antennas has a significant influence on the shape of the main radiation, and that it generally widens it.

The antenna spacing can of course be reduced either by changing the spatial spacing while maintaining the fundamental frequency of the characters supplied to them, or by changing this fundamental frequency while maintaining the spatial spacing of the antennas.

The antenna system 10 '' '' of FIG. 11 differs from that of FIG. 5 in that the antennas 16-21 are arranged at intervals of three quarters of a wavelength. The curve D of FIG. 12 relating to this antenna system is identical to the curve D 'of FIG. 6, from which it can be seen that the symbols applied to the antennas of the antenna system 10' '' 'have the same frequencies as those of the corresponding antennas of the antenna system 10 'of FIG. 5 applied characters. The curves F '' '', G '' '' and H '' '' each represent one half of the directional characteristic of the antenna system 10 '' '' for the values <Formula> and 2 (Pi) of the quantity (Omega) (sub ) ht. The radius of the auxiliary circle E is 2 (Pi) a, so it is equal to <formula>. The curve F '' '' shows that as a result of the increased spacing between the antennas, two main radiations are present during part of the scanning period. The sharper concentration of the main radiation achieved by this distance measurement is admittedly advantageous, but the occurrence of two main radiation can be disadvantageous for some purposes.

Under certain circumstances it may be desirable to suppress the secondary radiation entirely. This can easily be achieved with the device according to the invention by providing a sufficiently large number of antennas and reflective auxiliary antennas and feeding the antennas with characters whose amplitudes and frequencies are in a suitable ratio to one another. The curves S, T and U of FIG. 13 show, for example, the directional characteristic of a

Antenna system with a large number of antennas arranged at intervals of half a wavelength each for certain values of (omega) (sub) ht. The number of antennas is so large that the graphic solution of equation (14) is approximately represented by the idealized curve V. This curve represents a pulse-modulated symbol, each pulse having a width k (Pi) determined by the number of antennas. It is evident that with a large number of antennas the pulse duration is short and the radiation is sharply concentrated, with no secondary radiation. A Fourier analysis of curve V shows that the constants K (sub) o and K (sub) m of equation (14) are no longer the same, as was the case with equations (13) and (15), rather, they change from member to member of the equation. If only one main radiation is to be present, the exact mutual spacing of the antennas results from: Where

(Lambda) is the wavelength corresponding to the fundamental frequency of the characters applied to the antennas, and

k (lambda) is the width of the pulse curve V.

A distance between the antennas exceeding the value given by equation (17) causes the emergence of two main radiations at the beginning and at the end of each sampling period. Curves T and U of FIG. 13 represent the directional characteristic of such an antenna system for the values <Formula> and 2 (Pi) of the quantity (Omega) (sub) ht, while curve S shows the directional characteristic for (Omega) (sub) represents ht = (Pi) + k (Pi). The curves of Fig. 13 are applicable to both antenna systems with an even number as well as those with an odd number of antennas. The only difference in both cases is that with an even number of antennas the successive main rays have opposite signs, while with an odd number of antennas the sign of all main rays is the same.

Based on equation (5), the symbols applied to the antennas of the antenna system 10 of FIG. 5, which are arranged at the same intervals, can be expressed by the following equations, in which the index numbers designate the individual antennas:

e (sub) 13 = E (sub) 13 cos (omega) (sub) ct (18)

e (sub) 14 = E (sub) 14 cos ((omega) (sub) c + (omega) (sub) h) t (19)

e (sub) 15 = E (sub) 15 cos ((omega) (sub) c + 2 (omega) (sub) 2) t (20)

e (sub) 12 = E (sub) 12 cos ((omega) (sub) c - (omega) (sub) h) t (21)

e (sub) 11 = E (sub) 11 cos ((omega) (sub) c - 2 (omega) (sub) h) t (22)

in which

(Omega) (sub) c is the angular frequency of the character supplied to the antenna 13.

If an considers the symbols expressed by the above equations as individual frequency components of an oscillation originating from a common source, this common oscillation results from the addition of equations (18) to (22), after a simplification based on the assumption that all voltages E (sub) 11 to E (sub) 15 have the same value E, to:

e (sub) s = E cos (omega) (sub) ct (1 + 2 cos (omega) (sub) ht + 2 cos 2 (omega) (sub) ht) (23)

It is clear that the equation (23) corresponds to that of a modulated character whose carrier wave is represented by the equation

e (sub) o = E cos (omega) (sub) ct (24)

and its modulation envelope by the equation e (sub) m = (1 + 2 cos (omega) (sub) ht + 2 cos 2 (omega) (sub) ht) (25)

is expressed. The modulation components represent a modulation symbol with two frequency components. In accordance with general modulation theory, the first term of equation (23) is the carrier wave component, the second term represents upper and lower sideband modulation components, which are spaced (omega) (sub) ht from of the carrier wave components and the third term also represents upper and lower sideband components, but their distance from the carrier wave components is 2 (omega) (sub) ht.

The most general form of equation (23) for an antenna system with an odd number n of antennas, which are excited by carrier characters whose amplitude values are so large that they combine to produce a carrier character modulated with a periodic pulse, can be written as follows: Where

K (sub) o = 1 (when the antennas are excited by carrier characters with the same amplitude, K (sub) m is equal to one and K (sub) o is equal to K (sub) m)

m is the number of the link in the series.

m '<formula> and

1-b is that fraction of the pulse period during which a pulse of the pulse modulation appears.

Similarly, the most general form of the equation for antenna systems with an even number n of antennas excited in the aforementioned manner is: Where

m 'is equal to n.

The general equation (26) is of interest in those cases in which carrier symbols of different amplitudes are fed to the individual antennas, thereby reducing or suppressing the secondary radiation, as was mentioned in connection with FIG. In cases in which the maximum power of the individual vibration generators 5-9 is limited and it is therefore desirable to generate the main beam with the greatest available energy, the amplitude of the characters supplied to the individual antennas is dimensioned to be the same. This means that in the general equation (26) all the coefficients K become one. Equation (23) can be derived directly from equation (26) for the case of five antennas.

For the case of an even number of antennas, the following equation can be derived from the general equation (26a), provided that all coefficients K in this equation are equal to one: (27)

The significance of the type and manner of modulation according to the invention is evident from the exemplary embodiments of the device according to the invention described below.

14 shows a preferred embodiment of the device according to the invention. This is that of FIG. 1 essentially lichen the same, with the difference that here means are provided for generating a modulated carrier character with sideband modulation components and the device contains character channels via which at least the sideband components of the modulated carrier character are fed to the individual antennas in such a way that the frequency of the fed components steadily increases in the direction from one external antenna to the other external antenna.

The device contains a first input circuit consisting of a transformer 28 and a second input circuit consisting of transformers 31 and 32. The primary winding 29 of the transformer 28 is a generated by the generator 30 carrier symbol of the frequency f (sub) c, while the transformers 31 and 32 modulation symbols are supplied, the frequency components of which are in a certain ratio to the distance of the individual antennas 11-15 from a common reference point. In the present case, the modulation symbol has two frequency components f (sub) h and 2f (sub) h and is generated by the generator 51 consisting of two synchronized oscillation generators. The input circuit 35 of the oscillation generator 33 is tuned to the frequency f (sub) h and its output circuit is connected to the transformer 32, while the oscillation generator 34 has an input circuit 36 tuned to the frequency 2f (sub) h and an output circuit connected to the transformer 31 having. The oscillation circuits of these oscillation generators are mutually coupled in order to achieve an exact synchronization of the oscillations. Also in the device is a balanced modulator 50 containing electron tubes 37 and 38 for feeding differently modulated carrier waves are provided to the individual antennas. The input electrodes of the tubes 37 and 38 are connected in a push-pull connection to the secondary winding 39 of the transformer 28, a center tap of the secondary winding 39 being connected to the cathodes of the two tubes via the series-connected secondary windings of the transformers 31 and 32 and via earth. The output circuits of tubes 37 and 38 contain a number of matched coupling transformers 40-44 through which pairs of modulators 55 and 56 to the output circuit of tube 37, another pair of modulators 58 and 59 to the output circuit of tube 38 and a modulator 57 is coupled to the output circuits of both tubes.

The transformers 40-44 are individually coordinated in such a way that they supply the individual modulators 55-59 with different frequency components of the modulated carrier character produced in the modulator stage 50. The transformer 42 is tuned to the carrier wave component, ie to the frequency f (sub) c of the generator 30. The transformer 41 is to the lower frequency component f (sub) c + f (sub) h and the transformer 40 is to the higher frequency component f (sub) c + 2f (sub) h of the upper sideband of the modulated carrier symbol, while the transformers 43 and 44 are tuned to the higher frequency component f (sub) c - f (sub) h and to the lower frequency component f (sub) c - 2f (sub) h of the lower sideband of the modulated carrier symbol are matched.

A superimposed oscillation generator 65, which generates an oscillation f (sub) o, is also connected to the input circuits of the modulators 55-59. The output circuits of the modulators 55-59 are each connected to an antenna 11-15 of the antenna system 10 via combined band filter and amplifier units 66-70.

The vibrator 33 generates a frequency component f (sub) h whose waveform is defined by the term cos (omega) (sub) ht. Curve B of Fig. 2 represents a period of this frequency component. The oscillator 34 generates a second frequency component 2f (sub) h from the waveform cos 2 (omega) (sub) ht. Curve C in FIG. 2 represents two periods of this component. These two frequency components are combined in the input circuit of modulator stage 50 to form the modulating symbol shown by curve D in FIG . Since the modulating symbol has two frequency components, the modulated carrier symbol is made up of the carrier wave components and an upper and lower sideband, each with two frequency components. The transformers 40-44 each select a modulation component and feed this to the modulators 55-59 in the order mentioned.

The frequency f (sub) c of the carrier symbol generated by the generator 30 is expediently selected to be so low that the transformers 40-44 can easily separate the modulation components from one another. For this reason, the modulation components fed to the modulators 55-59 are then superimposed by the higher frequency oscillation coming from the oscillation generator 65 in order to generate modulated carrier characters of frequencies suitable for transmission f (sub) o + (f (sub) c - 2f (sub) h) ... f (sub) o + (f (sub) c + 2f (sub) h). The superimposed vibrations are expediently selected in units of the superimposed components with the sum frequencies f (sub) o + f (sub) c - 2f (sub) h ... f (sub) o + f (sub) c + 2f (sub) o and forward it to the antennas. The middle antenna receives only the carrier wave component f (sub) o + f (sub) c. The frequencies

These components are equidistant from one another in the frequency band. The gain of the amplifiers in units 66-70 is expediently chosen so that the characters fed to the antennas have the same amplitude. In the case of a vertical dipole antenna arranged along a horizontal straight line, it follows from the earlier explanations that the directional characteristic of the antennas fed in this way in the horizontal plane for the values (Pi), <Formula> and 2 (Pi) of the quantity ( Omega) (sub) ht has the form shown by curves F, G, and H of FIG.

From the explanations relating to FIG. 2 it can be seen that the directional coefficient 2 (Pi) a cos (alpha) contains a factor a expressing the antenna spacing, the value of which is related to the fundamental frequency of the carrier symbol supplied to the antenna system, but is related to the size (Omega) (sub) ht

is completely independent. On the other hand, the quantity (omega) (sub) ht is independent of the antenna spacing and of the fundamental frequency of the modulated carrier character fed to the antenna system. From this it follows that the speed of the scanning caused by the main beam can easily be regulated, since it is only determined by the value of the frequency components f (sub) h 2f (sub) h of the modulated carrier character created in the modulator and therefore simply by appropriate settings of the Operating frequencies of the vibrators 33 and 34 can be changed. However, any change in the frequency of these oscillators only affects the scanning speed and has no influence on the shape of the main radiation or the secondary radiation. In contrast, changes affect the frequency of the carrier wave generator 30, which frequency represents the fundamental frequency of the carrier character supplied to the antenna system only the form of the radiation and have no influence on the scanning speed. The great importance of this characteristic property of the device according to the invention is readily apparent to the person skilled in the art.

15 shows a device essentially the same as the device according to FIG. 14, with the difference that here, as in the case of FIG. 5, an antenna system 10 'with an even number of antennas is used. The parts corresponding to the parts in FIG. 14 are provided with the same reference numerals. The carrier character supplied to the antenna system contains the frequency components <Formula> in accordance with the representation according to FIG. 6, which shows the directional characteristic of this antenna system. The addition of these frequency components results in a modulating symbol of the form shown by curve D 'in FIG. Therefore, the generator 51 'serving to generate the modulation mark contains an oscillation generator 33' for generating the modulating frequency components <Formula>, an oscillation generator 34 'for generating the modulating frequency components <Formula> and an oscillation generator 71 for generating the modulating frequency components <Formula>. These oscillation generators are synchronized by mutual coupling, as in the case of the device according to FIG is fed to the two tubes mentioned in the same phase. The carrier is suppressed in the modulator so that only the modulation sideband frequency components appear in the output circuit of the modulator. The transformers 40 ', 41', 43 ', 44', 73 and 74 connected to the output circuit of the modulator are each matched to one of these components. The selected components are fed to a modulator 55 ', 56', 58 ', 59', 75 and 76 each, together with superimposed vibrations originating from the vibration generator 65 and having the frequency f (sub) o; From the superimposed vibrations <Formula> transferred in the output circuits of the modulators, the units 66 ', 67', 69 ', 70', 77 and 78 preferably become the components of the sum frequency selected, amplified and fed to the antennas. These components are equidistant from one another in the frequency band. The frequency components <formula> forming the upper modulation sideband are fed to the antennas 19, 20 and 21 located on one side of the center point of the antenna system, while the frequency components <formula> and <formula> forming the lower sideband lie on the other side of the center point of the antenna system Antennas 18, 17 and 16 are fed.

The band filter and amplifier units 66 ', 67', 69 ', 70', 77 and 78 are expediently set so that the characters fed to the antennas have the same amplitude. If it is a vertical dipole antenna arranged along a horizontal straight line at intervals of half a wavelength, it follows from the earlier explanations that the directional characteristic of the antennas fed in this way in the horizontal plane for the values <Formula> and 2 (Pi) the size (omega) (sub) ht has the form shown by the curves F ', G' and H 'of FIG.

If necessary, the bandpass filter amplifier units 66-70 of FIG. 14 or the corresponding units 66 ', 67', 69 ', 70', 77 and 78 of FIG. 15 can also be replaced by carrier wave generators, or each contain such a generator. In this case, the superimposed frequency components that arise in the output circuits of the modulators 55-59 are used to synchronize these generators. Such an arrangement may be desirable in those cases in which the aforementioned units would otherwise not be able to deliver the high output power that may be required.

16 shows a device which is suitable for scanning a predetermined space section in two directions normal to one another. The scanning pattern of this device is a grid consisting of parallel lines, as it is used in television.

The device according to FIG. 16 can be understood as a plurality of devices according to FIG. 14, each of these devices working with a basic frequency that differs slightly from that of the others. The parts also occurring in FIG. 14 are provided with the same reference numerals as there and those of the unmarked parts which correspond in their position to parts marked are similar to these in every respect, only that they belong to symbol channels operating at different frequencies. The device contains 25 symbol channels and antennas and the frequencies belonging to these are identified by the reference symbols m (sub) 1, m (sub) 5, n (sub) 1-n (sub) 5, o (sub) 1-o (sub ) 5, p (sub) 1-p (sub) 5 and r (sub) 1-r (sub) 5, the frequencies belonging to the same longitudinal row of antennas with the same letters and the frequencies belonging to the same transverse row of antennas with same index numbers are designated.

The device also contains a modulation generator 51 of the device according to FIG. 14, which is used to induce the horizontal scanning movement, and a modulation generator 79 which is used to induce the vertical downward movement and generates oscillations at the frequency f (sub) v and 2f (sub) v, the output circuit of which is on an input circuit of a modulator 80 is connected. The carrier wave generator 30 is connected to the other input circuit of this modulator. The earlier explanations show that the frequency components f (sub) c, f (sub) c + f (sub) v and f (sub) c + 2f (sub) v of the modulated carrier waves produced in the output circuit of the modulator 80 are suitable for this are to cause a vertical scanning movement of the beam of the antenna system. These modulation components are separated out individually and fed to a group I of band filters and modulators containing the band filter of the modulator 50, in which they are modulated with the horizontal modulation components f (sub) h and 2f (sub) h of the generator 51 labeled Y. The modulation components reliably resulting from this are shown in FIG. 16. Each of the bandpass filter and modulator units of group I separates out one of these modulation components and routes it to a further group II of modulators containing the modulators and bandpass filters 40-44 and 55-59 du band filters, in which the vibrations marked with X from the frequency f (sub) o of a superimposed vibration generator 65 are superimposed. The resulting modulated characters m (sub) 1 - m (sub) 5, n (sub) 1 - n (sub) 5, o (sub) 1 - o (sub) 5, p (sub) 1 - p ( sub) 5 and r (sub) 1 - r (sub) 5 then pass via the group III of band filters and amplifiers containing the band filters and amplifiers 66-70 to the antenna system containing the antennas 11-15.

The frequency designations in FIG. 16 show that the antennas are supplied with symbols, the frequency of which in each longitudinal row of antennas is proportional to the distance between the antennas from the left end of the row and in each transverse row with the distance between the antennas and the lowermost antenna Intervals increases. In particular, the antennas of the longitudinal rows located on one side of the central longitudinal row of antennas with oscillations resulting from the second modulation of the modulation components of the upper sideband of the first modulation and the antennas of the longitudinal rows located on the other side of the central longitudinal row with them from the second Modulation of the modulation components of the lower sideband of the first modulation resulting oscillations fed, the oscillations fed to the antennas located on one side of the central antenna of each longitudinal row from the modulation components of the upper sideband of the second modulation and the antennas located on the other side of the central antenna of each longitudinal row supplied vibrations consist of the modulation components of the lower sideband of the second modulation. The characters fed to the antennas of each longitudinal row thus differ in frequency f (sub) h, which causes the beam to scan horizontally at a preferably higher speed, while the characters fed to the antennas of each transverse row rotate by frequency f (sub) v differentiate, which results in a scanning movement of the beam in the vertical direction with preferably a lower scanning speed.

The device according to the invention is particularly suitable for operation with pulse modulation. In this type of operation, the carrier characters generated by the generator 30, for example be amplitude modulated either in the generator itself or in a subsequent modulator stage by a modulating symbol, which consists of short, periodic pulses in relation to their repetition period. This has the advantage that all devices of the facility can be operated with a high peak power in relation to their continuous output, so that a high output power of the facility is achieved. The beam does not carry out a continuous scanning movement, rather it moves step by step, with each step corresponding to an impulse of the modulating symbol. The repetition period of these pulses can be chosen so that the beam scans an angle of 180 ° through successive steps. On the other hand, it is also possible to make the repetition period of the pulses so long and the pulses themselves so short that the beam emerges only once in a certain direction during each scan of the angle of 180 °, this direction changing with each subsequent scan of the above Angle changes so that the beam travels in overlapping steps over the entire angle during a number of sampling periods. This method can advantageously be used at a very high scanning speed, that is to say at a high value of the quantity (omega) (sub) h, and causes the actual scanning to be slowed down. Furthermore, the repetition period of the pulses can also be such that the scanning steps of the beam carried out during a scanning period fall between the scanning steps carried out during a previous scanning period, so that a form of scanning similar to the interlaced method known in television results.

In connection with the directional characteristics shown in FIG. 2, it was pointed out that, for the sake of simplicity, this figure shows only one half of the directional characteristics. In many cases it can be desirable to prevent the creation of two oppositely directed main rays. This can be achieved simply by using suitable directional antennas or reflector antennas, or in other known ways. If it is desired that the main beam should only scan at an angle that is less than 180 °, this can be achieved by pulse modulation, in which the modulation symbol controls the operation of the device so that symbols are only fed to the antennas during that time during which the main ray is within the desired scanning angle.

17-21 of the drawing show exemplary embodiments of the receiving device according to the invention for scanning a room in which there is an object which reflects characters transmitted by a transmitting station or which itself emits characters.

The device according to FIG. 17 comprises an antenna system 110 consisting of receiving antennas 111-115 arranged in a straight row. The antennas can, for example, be vertical dipole antennas arranged in a horizontal row. Furthermore, the device contains character channels connected to the antennas with modulators for modulating the carrier character received by at least one of the antennas with a modulating character of a certain frequency and the carrier character received by at least one other antenna with a modulating character of another

Frequency. An input circuit of the said modulators 116-120 is connected to one of the antennas each and another input circuit of the modulators is connected to a modulating symbol generator 121-125, each of which has a frequency different from the frequency of the other generators. The frequencies of the generators are related to the distance of the antennas from a common reference point, as will be explained in more detail below. Finally, the device comprises means for utilizing those modulation components of the received carrier characters modulated in the above-mentioned manner which are only in phase for one receiving direction. This direction of reception changes continuously and periodically over a certain angular range, so that the device has a sharply directed reception characteristic of variable direction. These means include intermediate frequency band filter and amplifier units 126-130, the input circuits of which are connected to the output circuit of one of the modulators 116-120 and the output circuits of which are connected to a unit 131 common to all, which has one or more intermediate amplifier stages, a demodulator and for utilization the demodulated characters may contain suitable device.

FIG. 18 shows the antenna system 110 of the device according to FIG. 17 by itself. It is assumed that each of the antennas 111-115 of the antenna system receives a symbol, the direction of arrival D of which forms an angle (alpha) with the straight line connecting the antennas, and that the distance from the starting point of this symbol is large in relation to the mutual distance d of Antenna is. It is also assumed that the antennas are arranged at equal intervals and that the from The characters received by the central antenna 113 are expressed by the following equation:

e (sub) c = E (sub) c cos (omega) (sub) ct (28)

In this equation:

e (sub) c is the instantaneous value of the symbol voltage received by the antenna 113,

E (sub) c is the peak value of this character voltage

(Omega) (sub) c the angular frequency 2 (Pi) f (sub) c, in which f (sub) c is the frequency of the received character and

t the time.

The character received by the neighboring antenna 112 is determined by the following equation:

e '(sub) c = E (sub) c cos ((Omega) (sub) ct - (Psi)) (29)

In this drawing means

e '(sub) c is the instantaneous value of the symbol voltage received by antenna 112 and

(Psi) the phase difference between the characters received by antennas 112 and 113.

The size of the phase angle is determined by the equation

(Psi) = 2 (Pi) a cos (Alpha) (30)

In this is , means the mutual spacing of antennas 112 and 113 in terms of the fractions of the wavelength of the received character.

When the value of (Psi) on given by the equation (39) is inserted into the equation (29), one obtains for the from the antenna 112 received character voltage:

e '(sub) c = E (sub) c cos ((Omega) (sub) ct - 2 (Pi) cos (Alpha)) (31)

It can be shown in the same way that the symbol voltage received by any other antenna of the antenna system is expressed by the following equation:

e (sub) c = E (sub) c cos ((Omega) (sub) ct + 2 (Pi) am cos (Alpha)) (32)

In this means

m a factor indicating the position of the antenna in question in relation to the central antenna 113, which is negative for the antennas 111 and 112 and positive for the antennas 114 and 115.

The characters received by antennas 111-115 are fed to modulators 116-120. The modulator 118 connected to the central antenna 113 receives a modulator symbol from the generator 123, which is expressed by the following equation:

e (sub) o = K E (sub) o cos (omega) (sub) ot (33)

In this is

Not a realizable constant,

E (sub) o is the amplitude of the modulating symbol voltage and

(Omega) (sub) o the angular frequency 2 (Pi) f (sub) o, where f (sub) o is the frequency of the modulating symbol.

As a result, a modulated symbol of the form results in the output circuit of the modulator 118:

e (sub) m = K E (sub) o E (sub) c cos (omega) (sub) ct cos (omega) (sub) ot (34)

It is known that this modulated symbol has a component with a frequency which is the same as the sum of the frequencies of the received symbol and the modulating symbol and a second component with a frequency which is the same as the difference between these frequencies. The equation of the difference frequency components is: (35)

This component, which represents an intermediate-frequency symbol, is separated out by the bandpass filter of the unit 128, amplified by the amplifier of this unit and fed to the input circuit of the unit 131.

According to the invention, the other generators 121, 122, 124 and 125 generate modulating characters, the frequencies of which are different among themselves. The modulating symbol produced by any of these generators has the form:

e '(sub) o = K (sub) mE (sub) o cos ((omega) (sub) ot - m (omega) (sub) ht)) (36)

Here is

K (sub) m a selectable constant and

(Omega) (sub) h is the angular frequency 2 (Pi) f (sub) h, where f (sub) h represents a frequency which differs from the frequency f (sub) o des according to the mutual distance between the antennas and the desired scanning speed by the generator 123 generated modulating character differentiates. This relationship is explained in more detail below with the aid of equations (38) and (39).

It can easily be shown that the difference frequency component of the modulated carrier character arising in the output circuit of any one of the modulators 116, 117, 119 and 120 and extracted and amplified by any one of the units 126, 127, 129 and 130 is given by the following equation: (37)

The general form of the equation expressing the combined difference frequency components appearing in the common output circuit of the various modulators, which applies to every receiving device according to the invention with an odd number n of antennas, is as follows: (37a)

In this, K (sub) o and K (sub) m are selectable constants, while <formula> is.

For the case of the five antennas shown in FIG. 17, the combined difference frequency component appearing in the input circuit of the unit 131 results in: (37b)

Equations (37), (37a), and (37b) show that the difference frequency components have a frequency equal to that of the difference frequency or intermediate frequency components supplied from the unit 128 to the input circuit of the unit 131 and expressed by the equation (35) against them but show the following phase difference:

(Psi) = m (2 (Pi) a cos (Alpha) + (Omega) (sub) ht) (38)

The phase difference (PsI) of all difference frequency components becomes zero for each value of t if (Alpha) has the following value: (39)

Equations (38) and (39) are valid for the difference frequency components appearing in the output circuit of all units 126, 127, 129 and 130. As a result, the value of (alpha) given by equation (39) for each selected value of t is such that all of the input circles in the output circles Units 126-130 appearing difference frequency components have the same phase and therefore add up in the input circuit of the unit 131. For values of (alpha) which do not satisfy equation (39), difference frequency components arise in the output circuits of the units 126-130 which are not in phase with one another and, as a result, the size of the input character of the unit 131 is reduced. From this it follows that the receiving device according to the invention has a sharply directed receiving characteristic, the maximum of which lies in the direction for which the value of (alpha) satisfies equation (39) for any selected value of t. It is evident that the direction of this maximum sensitivity changes continuously and periodically within a certain angular range, since the value of (alpha) satisfying equation (39) depends on the value t. This scanning movement of the reception characteristics of the device according to the invention can be used for many purposes, in particular for the determination of the location of an object which reflects emitted characters or which emits its own characters in space, e.g. an aircraft.

Equations (38) and (39) are important in other respects as well. They show that the speed of the scanning movement of the receiving directional characteristic of the device for any given antenna spacing a changes with the frequency difference (omega) (sub) h between the modulating characters fed to the character channels of the individual antennas, and that the scanning speed also changes for each given antenna The value of the frequency difference (omega) (sub) h changes inversely proportional to the antenna spacing a and <not readable> finally the ratio <not readable> to a must be the same for each neighboring pair of antennas, so that all the difference frequency components in the input circuit of the unit 131 add up. With the same antenna spacing, the characters fed to the character channels of all pairs of adjacent antennas have the same frequency difference. In the case of unequal antenna spacings, the above-mentioned rule relating to the ratio of (omega) (sub) h to a requires that the frequency of the symbol channel applied to a given antenna and the frequency of the modulated symbol applied to the symbol channel of a reference antenna correspond to the mutual spacing of these there is a proportional difference between the two antennas. For any given spatial antenna spacing, the carrier waves received by the individual antennas are modulated with different modulation symbols, the frequency of which increases proportionally to the distance between the individual antennas and a reference point common to all antennas. If the antenna spacing is the same, the carrier characters received by the individual antennas are modulated with modulating characters with frequencies that are different from one another and are equally spaced from one another in the frequency band.

If the starting point of the received carrier characters is at a fixed distance from the device, the character supplied to the unit 131 has the shape of a character with amplitude pulse modulation as a result of the continuous scanning movement of the reception directional characteristic of the device, although the received character itself does not modulate at all or only usually may be amplitude modulated. If the scanning speed of the reception directional characteristic is sufficiently high, these modulation components of the character can be detached from the character by means of the demodulator contained in the unit 131 and used in the same way as in FIG any conventional device using pulse modulation. This possibility also exists if the starting point of the characters is movable, since the speed of this movement is in any case small in relation to the scanning speed. The evaluation device of the unit 131 can accordingly be, for example, a sound reproduction device for reproducing speech or music with which the received character is modulated. In this context, the device according to the invention can be used to differentiate between character sources which are spatially separated from one another, but operate at the same frequency or with frequencies so close to one another that they fall within the pass range of several or all of the character channels of the device.

Furthermore, the device according to FIG. 17 can of course also be used to determine the direction of a character source. This type of application of the invention will be dealt with on the basis of another exemplary embodiment.

The reception directional characteristic of the device according to the invention can have a main reception direction and one or more secondary reception directions depending on the number and mutual spacing of the antennas, as well as depending on the mutual amplitude ratio of the different modulating characters fed to the antenna character channels. In addition, the shape of the directional characteristic changes in the main receiving direction with the angle that this direction makes with the straight line connecting the antennas. The speed of the scanning movement carried out by the receiving characteristic is similar to the scanning speed in the case of the device according to FIGS. 1-16, from the frequency difference between the modulating characters fed to the character channels of the individual antennas. It is evident that the modulation symbols generated by the generators 121-125 can also be regarded as modulation components of a modulated carrier wave at different frequencies. 19 shows a correspondingly designed embodiment of the receiving device according to the invention. This corresponds essentially to the device according to FIG. 17 and the same parts are provided with the same reference numerals. The only difference is that the device according to FIG. 19 has means for generating a symbol with modulating symbols consisting of harmonics of the fundamental frequency for the symbol channels of the individual antennas in order to modulate the carrier symbols received by them with the different frequency components mentioned. This arrangement is particularly suitable for those devices in which the mutual antenna spacings are proportional to one another, since the mentioned frequency components are also in mutually proportional spacings in the frequency band.

The device comprises a <not readable> input circuit consisting of an input transformer 132, to which the carrier character generated by the generator 133 is fed. A second input circuit consists of transformers 134 and 135, the secondary windings of which are connected in series. A symbol is fed to these transformers which contains frequency components which lie in the frequency band in the spacings of the antennas of the antenna system 110 which are proportional to the spacings measured from a common reference point, the frequency the lower frequency components of the desired scanning speed of the reception characteristics of the device is selected accordingly. This fundamental frequency component f (sub) h is generated by the oscillation generator 136, while the oscillation generator 137 generates the second harmonic 2f (sub) h of this oscillation. The oscillation circuits of these two oscillation generators are coupled to one another in order to keep them synchronous and their output circuits are connected to one of the transformers 134 and 135 each. The series-connected secondary windings of these transformers are connected between the central tapping point of the secondary winding of the transformer 132 and the cathode of the electron tubes 139 and 140 forming a modulator, so that the output currents of the oscillation generators 136 and 137 are fed to the input electrodes of these tubes with the same polarity. The secondary winding of the transformer 132 is connected to the input electrodes of said tubes in a push-pull circuit in order to supply them with the output current of the carrier character generator 133 with opposite polarity.

The output circuit of the tube 139 is connected to a band filter modulator unit 142 via a transformer 141 and to a similar unit 144 via a transformer 143, while a transformer 145 connects the tubes 139 and 140 in push-pull connection to a further band filter modulator unit 146. The output circuit of the tube 140 is connected via a transformer 147 to a band filter modulator unit 148 and via a transformer 149 to a similar unit 150. The transformers 141, 143, 145, 147 and 149 each have a modulation component in the output circuit of the modulator

138 resulting modulated carrier characters matched. The frequency of the generator 133 is expediently chosen to be so low that the transformers mentioned can easily perform this separation of the components.

A superimposed oscillation generator 156 is also connected to each input circuit of the modulators of the units 142, 144, 146, 148 and 150, which generates sum-frequency and difference-frequency superimposition vibrations of the modulation components supplied to the units mentioned in the output circuit of each modulator. The band filters of these units are tuned in such a way that either the superimposed oscillation of the sum frequency or that of the difference frequency is allowed to pass, depending on which one is desired. The output circuits of the units mentioned are connected to an input circuit of one of the modulators 116-120. Another input circuit of these modulators is connected to one of the antennas 111-115, while their output circuits are connected via bandpass filter amplifier units 126-130 to a common unit 131 ', which can contain one or more intermediate frequency amplifier stages, a demodulator for generating a control voltage .

The device mentioned in connection with the unit 131 of FIG. 17 for utilizing the demodulated characters consists in the present case of means controlled by the control voltage of the unit 131 'for displaying the direction of the starting point of the characters received by the antennas. These consist of a cathode ray tube 157, the input electrodes of which are connected to the unit 131 ', as well as a device for generating the deflection voltages for the vibrator 159 serving for the cathode ray, the synchronization circuit of which is connected to the vibrators 136 and 137 via a delay network 158 and whose output circuit is connected to the deflection electrodes 160 of the tube 157.

The mode of operation of the device according to FIG. 19 is essentially the same as that of the device according to FIG. 17 and only differs in the way in which the modulating characters are generated. The oscillation generator 136 generates the fundamental frequency component E (sub) h cos (omega) (sub) ht and the oscillation generator 137 the harmonic frequency component E (sub) h cos 2 (omega) (sub) ht of the character supplied to the modulator 138. A subcarrier symbol E '(sub) h cos (Omega)' (sub) ht generated by the generator 133 is also fed to this modulator at a comparatively lower frequency, and as a result, a modulated carrier symbol is produced in the output circuit of the modulator 138, the desired components of which are derived from the following Equation give: (40)

Transformers 141, 143, 145, 147 and 149 separate the various modulation components of this modulated carrier symbol and apply modulation components of the following form to modulators 142, 144, 146, 148 and 150:

e (sub) 142 = E '(sub) o cos ((Omega)' (sub) ot - 2 (Omega) (sub) ht) (41)

e (sub) 144 = E '(sub) o cos ((Omega)' (sub) ot - (Omega) (sub) ht) (42)

e (sub) 146 = E '(sub) o cos (omega)' (sub) ot (43)

e (sub) 148 = E '(sub) o cos ((Omega)' (sub) ot - (Omega) (sub) ht) (44)

e (sub) 150 = E '(sub) o cos ((omega)' (sub) ot - 2 (omega) (sub) ht) (45)

The oscillations (omega) 'o' of the superimposed oscillation generator 156 are also fed to the named modulators and these then feed the following superimposed oscillations of sum frequency to the modulators 116-120, which are separated out by their band filters:

In these equations is

(Omega) (sub) o = (Omega) '(sub) o + (Omega)' (sub) o '

As can be seen, equations (47), (49), (51), (53) and (55) satisfy equation (36) and, as a result, the modulating components applied to modulators 116-120 have the frequencies which are necessary to induce one in the Direction changeable, sharply concentrated reception directional characteristic of the device are required. The speed of the scanning movement of this receiving directional characteristic is, as the last equations show, only dependent on the value of the quantity (omega) (sub) h. As a result, the scanning speed can be adjusted by simply changing the frequencies of the vibrators 136 and 137 and adjusting them accordingly by means of equal control of transformers 141, 143, 145, 147 and 149 can be easily changed. A readjustment of the band filters of the units 142, 144, 146, 148 and 150 is generally not necessary, since these have a sufficiently large pass band at the relatively high frequencies of the superimposed oscillations. The shape of the reception characteristic depends on the amplitude ratio of the superimposed oscillations supplied by the modulators 142, 144, 146, 148 and 150 and can therefore be changed by changing the amplitude ratio of the oscillations supplied by the oscillation generators 136 and 137 or the degree of modulation in the individual modulators 142, 144, 146, 148 and 150, or by which both measures can be changed slightly.

The in-phase modulation components of the received symbols fed by the bandpass filter amplifier units 126-130 to the input circuit of the unit 131 'are amplified, demodulated and, after being amplified again, fed to the input electrodes of the cathode ray tube 157 in order to modulate the cathode ray. At the same time, sawtooth-shaped deflection voltages originating from the vibrator 159 are applied to the deflection electrodes 160 of the tube. The oscillation generator 159 is synchronized by the oscillations of the oscillation generator 136 and the delay network 158 controls this synchronization so that a scanning period of the cathode ray tube begins whenever the directional angle of the receiving device is zero.

Since the reception characteristic of the device continuously scans a certain solid angle, the character fed to the input circuit of the unit 131 'is in the form of a pulse-modulated one

Character, even if the received character itself is unmodulated or modulated with a modulating character. The cathode ray of the tube 157 is thus modulated by the pulse modulation components appearing in the output circuit of the unit 131 '. Since the receiving device effects your pulse modulation of the received character once during each scanning period and since the deflection of the cathode ray is synchronized with the scanning movement of the receiving characteristic, the pulse modulation components applied to the input electrodes of the tube generate a fixed one in the event that the starting point of the received character is immobile Point on the fluorescent screen of the tube. The position of this point on the path of the cathode ray on the luminescent screen is a measure of the direction of the starting point of the received characters.

The device according to FIG. 20 differs from that of FIG. 19 only in that the antenna system 110 ′ here consists of an even number of antennas 111-115 and 161. The addition of the sixth antenna 161 naturally requires the addition of a further unit 162, 163 consisting of a modulator, bandpass filter and amplifier to the same units 116, 126 to 120, 130, as well as a further bandpass filter modulator unit 164, which is identical to the corresponding units 142, 144, 146, 148 and 150 is. The unit 164 is connected to the electron tube 140 of the modulator 138 'via a transformer 165 which is matched to a modulation component of the modulated carrier character arising in the output circuit of the modulator 138', which will be discussed in more detail below.

The modulator 138 'of the present device is a balanced carrier suppressing modulator in which the output circuit of the carrier wave generator 133 is connected between the cathodes of the tubes 139 and 140 and the center tap of the secondary winding of the input transformer 132. The primary winding of the latter transformer is connected through transformers 134 ', 137' and 168. The vibrators 136 'and 137' and 168 generated modulation symbol components having harmonic frequencies <formula>, <formula>, and <formula>. The deflection system of the cathode ray tube 157 may be the same as in the case of the device of FIG. 19 and is omitted for the sake of simplicity. Of course, with respect to balanced modulator 138 ', the primary windings of transformers 141, 143, 145, 17, 149 and 165 must be inductively coupled to achieve balanced output.

The mode of operation of the device, with the exception of that of the modulator 139 ', is essentially the same as that of the device according to FIG which correspond to the fundamental frequencies and harmonics generated by the vibrators 136 ', 137' and 168. One of the following components is separated from these by the transformers 141, 143, 145, 147, 149 and 165 and fed to the band filter modulation units 142, 144, 146, 148, 150 and 164:

The band filters of the last-mentioned units separate out either the sum frequency components or the difference frequency components, as in the case of the device according to FIG. 19. The modulation components fed to the signal channels of antennas 111-115 and 161 accordingly have the frequency ratio required by equation (36), which brings about a sharply concentrated reception characteristic of variable direction.

In connection with this device containing an even number of antennas, it should be pointed out that for an even number n of antennas the most general form of the equation for the combined difference frequency components arising in the common output circuit of the various modulators is as follows:

In the equation:

K (sub) m is a constant dependent on the degree of modulation of the individual modulators; <Not readable>

m is the number of the link in the series and

m '= <formula>

Accordingly, the equation of the difference frequency components appearing in the input circuit of the unit 131 'of the device according to FIG. 20 results in:

FIG. 21 shows a receiving device which, like the transmitting device according to FIG. 16, is suitable for scanning a predetermined space segment in two mutually normal directions. The scanning pattern of this device also represents a grid consisting of parallel lines, such as is used on television.

This device can be understood as a plurality of devices according to FIG. 19, each of these devices operating with a basic frequency that differs slightly from that of the other. The parts also appearing in FIG. 19 are provided with the same reference numerals as there and those of the unmarked parts which correspond in their position to parts marked are similar to these in every respect, only that they belong to symbol channels operating at different frequencies. The structure of this receiving device is essentially the same as that of the transmitting device according to FIG. 16, with the difference that the various frequency components generated in the device are not fed to the antennas themselves, but only to the modulators connected to the antennas in order to appropriately transmit the received characters modulate.

The device also contains a modulation generator 136, 137 of the device according to FIG Output circuit is connected to an input circuit of the modulator 170. The carrier wave generator 133 is connected to the other input circuit of this modulator. From the previous explanations it follows that the frequency components f (sub) c, f (sub) c + f (sub) v and f (sub) c + 2f (sub) v of the modulated carrier wave produced in the output circuit of the modulator 170 are suitable for causing a vertical scanning movement of the reception directional characteristic of the antenna system. These modulation components are separated out individually and fed to a group I of band filters and modulators containing the bandpass filter and modulator 138. In these they are modulated with the horizontal modulation components f (sub) h and 2f (sub) h of the generators 136, 137, denoted by Y. The resulting modulation components are shown in Fig. 21. Each of the bandpass filter and modulator units of group I separates one of these modulation components and routes it to a further group II containing the modulators and bandpass filters 142, 144, 146, 148 and 150 of modulators and band filters, in which the vibrations labeled X from the frequency f (sub) o of the superimposed vibration generator 156 are superimposed on them. The resulting modulated characters m (sub) 1 - m (sub) 5, n (sub) 1 - n (sub) 5, o (sub) 1 - o (sub) 5, p (sub) 1 - p ( sub) 5 and r (sub) 1 - r (sub) 5 arrive at group III of modulators containing the modulators and amplifiers 116-120, which are connected to the antenna system containing the antennas 111-115.

From the frequency designations in Fig. 21 it follows that the last-mentioned modulators are supplied with symbols, the frequency of which in each longitudinal row of antennas is proportional to the distance between the antennas from the left end of the row and in each transverse row with the distance between the antennas and the lowest antenna Intervals increases. In particular, the modulators belonging to the antennas on one side of the central longitudinal row of antennas are made up with the the second modulation of the modulation components of the upper sideband of the first modulation resulting vibrations and the modulators belonging to the antennas of the longitudinal rows on the other side of the central longitudinal row with vibrations resulting from the second modulation components of the lower sideband of the first modulation, the modulators the oscillations fed to the antennas on one side of the central antenna of each longitudinal row consist of the modulation components of the upper sideband of the second modulators; the oscillations fed to the other side of the central antenna of each longitudinal row consist of the modulation components of the lower sideband of the second modulation. The characters fed to the modulators of the antennas of each longitudinal row thus differ by the frequency f (sub) h, which causes the receiving directional characteristic to scan horizontally at a preferably higher speed, while the characters fed to the modulators of the antennas of each transverse row vary by the frequency f (sub) h differentiate, which results in a scanning movement of the reception directional characteristic in the vertical direction, preferably at a lower speed.

As in the case of the device according to FIG. 19, the output circuits of all modulators of group II are combined to form a common intermediate frequency channel and connected to the unit 131 '. The output of this unit is supplied to the cathode ray tube 157 to modulate its cathode ray. In view of the fact that the receiving directional characteristic of the device executes a scanning movement in two directions, in addition to the generator 159 for generating the

Deflection voltage for the horizontal deflection of the cathode ray is provided by a second generator 171, which is connected to the generator 169 via a delay network 173 identical to the delay network 168 and supplies the deflection voltage for the vertical deflection of the cathode ray causing deflection electrodes 172.

The reception characteristic of each of the receiving devices according to FIGS. 17-21 generally comprises a main receiving device and one or more undesired secondary receiving directions of considerably lower sensitivity. The sensitivity in these secondary reception directions can be further reduced by regulating the degree of modulation of the various modulators used, e.g. the modulators 116-120 of FIG. 17, in such a way that the difference frequency components resulting in the output circuit of the modulators have different amplitudes. With regard to the general equations (37a) and (62), this means that the various coefficients K (sub) o and K (sub) m are made unequal. In this case, too, the general equations mentioned are valid if the coefficients K (sub) m are only equal in those terms of the equations which express the difference frequency components generated in those pairs of modulators that are at the same distance from the center of the antenna system Antenna pairs belong.

22-26 of the drawing show embodiments of combined sending and receiving directions according to the invention, which are suitable for determining the location of an emitted symbol reflecting object in space.

FIG. 22 shows such a device with an antenna system 210 which comprises the antennas 211-220. The antenna Nines, which can usefully be vertical dipole antennas arranged along a horizontal straight line, are preferably divided into two groups 210 (sub) a and 210 (sub) b, each lying along a horizontal straight line. The antennas expediently have the same spacing, depending on the desired shape of their directional characteristic. In most cases, it is most expedient to measure these distances equal to half the wavelength which corresponds to the fundamental frequency of the characters supplied to the antenna system 210 (sub) a. The manner in which the antenna spacings influence the directional characteristic has been explained in detail in connection with FIGS. 1-13 of the drawing.

The device according to FIG. 22 further comprises means for feeding carrier characters of different frequencies to at least two antennas of antenna group 210 (sub) a of the antenna system. These means include a generator 221 for generating characters with frequency components dependent on the number and mutual spacing of the antennas, the characters fed to the character channels of the individual antennas in a predetermined ratio to the distance of the antenna in question from a reference point common to all antennas stand. In the present case, in which each antenna group comprises five antennas, the carrier symbol generated by the generator 221 has two frequency components f (sub) h and 2f (sub) h, the frequency of which accordingly corresponds to the distances between the antennas and the central antenna used as a reference point. Of course, the antenna groups can contain further antennas and the antenna spacings can also be different from one another, wherein the carrier symbol mentioned can also have further frequency components or those with a value deviating from the specified value.

Furthermore, the device contains means, connected to the generator 221, for generating a plurality of carrier characters of different frequencies. These means comprise a carrier character generator 222 for generating a subcarrier character with the frequency f (sub) c and a balanced modulator 223, the input circuit of which is connected to the output circuit of both generators mentioned. The output circuit of the modulator 223 is connected to the unit 224, which consists of the band filters and modulators 225-229 ) c + 2f (sub) h of the modulated character appearing in the output circuit of the modulator 223 are matched. The frequency f (sub) c of the subcarrier symbol is expediently selected to be so low that the band filters of the unit 224 can easily separate these frequency components. For this reason, a superposition generator 230 is provided for generating a superposition oscillation with a higher frequency f (sub) o, by means of which superposition oscillations with higher frequencies f (sub) o + (f (sub) c - 2f (sub) h) are generated from the aforementioned frequency components ) to f (sub) o + (f (sub) c + 2f (sub) h), which are suitable for transmission by the antennas. The output circuit of this generator 230 is connected to the input circuit of each of the modulators of the unit 224. A band filter amplifier unit 231-235 is connected to the output circuit of each band filter and modulator 225-229, and the output circuits of these latter units are each connected to one of the antennas 211-215. The band filters of these last-mentioned units separate the sum frequency components f (sub) o + f (sub) c - 2f (sub) h to f (sub) o + f (sub) c + 2f (sub) h of the superimposed oscillations and carry them out The amplifiers of these units expediently have such a degree of amplification that the vibrations fed to the antennas have the same amplitudes.

The beam emanating from the antenna group 210a and executing scanning movements is reflected back by an object located approximately in this space and received by the antenna group 210b. These antennas are followed by character channels which contain means for modulating the carrier characters received by at least two antennas of group 210b with modulating characters, the frequencies of which are partly different from the frequencies of the characters supplied to the antennas of antenna group 210a and partly different from each other by at least the same amount are by which the characters supplied to the frequencies of the antenna group 210a differ from each other. Some of the modulation components resulting in this way are only in the same phase for a certain receiving direction and this receiving direction changes continuously in accordance with the scanning movement of the beam emitted by the antenna group 210a.

Said means for modulating the received carrier characters comprise devices for deriving the modulating characters from the characters generated by the generator 221 for modulating the transmitted carrier wave. These devices include a balanced modulator 236 which has an input circuit connected to the output circuit of the generator 221 via an adjustable phase shifter 237 and a further input circuit connected to the output circuit of the carrier wave generator 222. The output circuit of the modulator 236 is connected to the input circuit of the unit 238 consisting of band filters and modulators 139-243, the band filters of which are connected in front of the modulators to one of the frequency components f (sub) c; f (sub) c + f (sub) h and f (sub) c + 2f (sub) h of the modulated character appearing in the output circuit of the modulator 236 are matched. In the modulators, the input to these frequency components is means 238 the superimposed oscillation generated by the superimposed oscillation generator 244 with the frequency f (sub) o superimposed. These superimposed vibrations <Formula> reach the units 245-249, which consist of band filters and modulators. The band filters connected to one input circuit of the modulators of these units separate out the difference frequency components <Formula> of the superimposed oscillations and feed them to the aforementioned one input circuit of the modulators. Another input circuit of these modulators is each connected to one of the antennas 216-220 of the antenna group 210b. The output circuits of the modulators of the units 245-249 are connected to the input circuit of an intermediate frequency band filter and amplifier 251-255, the output circuits of which are connected to a common intermediate frequency amplifier 256. This is followed by a demodulator 257 and a low-frequency amplifier 258, the output circuit of which is connected to the input electrodes of the cathode ray tube 259.

Furthermore, means controlled by the generator 221 are provided for deflecting the cathode ray of the tube 259 synchronously with the scanning movement of the symbol beam generated by the antenna group 210a. These means comprise an oscillation generator 260 for generating the deflection voltages, the synchronization circuit of which is connected via a delay network 261 to the output circuit of the generator 221, the output circuit of which is connected to a pair of deflection electrodes 202 of the tube 259.

The device works as follows:

The carrier character generated by the generator 222 is modulated in the balanced modulator 223 with the oscillations of the generator 221. The band filters of the units 225-229 but this and convert them into higher frequencies by superimposing them with the vibrations of the vibration generator 230. Since this conversion is carried out for the purpose of obtaining vibrations suitable for transmission, the sum frequency components of these superimposed vibrations are selected by the band filters of the units 231-235 and supplied to the antennas 211-215 of the transmitting antenna group 210a in order to be transmitted by them. As can be seen from FIG. 22, the symbols fed to the antennas have frequencies which increase by the same frequency amounts from one end antenna 215 to the other end antenna 211. The array of antennas excited in this way produces a sharply concentrated beam that scans over an angle of 180 degrees. The reason for this was explained in detail in connection with FIGS. have mutual phase differences that vary linearly with time. These changes in phase difference cause the beam to scan at a sinusoidal velocity.

As a result of the spatial distance between the antennas and the phase differences between the characters fed to the antennas, the field strength at an object located in the scanned space has the value zero, except during the time during which the scanning beam hits this object. It follows from this that the characters reflected by the said object are in the form of a carrier wave having amplitude modulation sidebands and having the frequency f (sub) o + f (sub) c of the character supplied to the antennas 213, so that so the reflected character actually represents a pulse-modulated carrier wave. This character is received by the antennas of the receiving antenna group 210b and fed to the input circuits of the modulators 245-249. Since the antennas mentioned are arranged at spatial intervals, there is a certain phase difference between the characters received by the individual antennas. In order to obtain the in-phase components of the received symbols, these symbols are modulated in the modulators 245-249 by the difference frequency components of the symbol supplied by the modulator 236 and superimposed with the oscillations of the oscillator 244. As has been shown in connection with the receiving devices according to FIGS have the same phase, this direction changing steadily within an angle of 180 degrees. The use of the modulation components with the modulation components of the emitted characters in the specified frequency ratio for modulating the received characters has the consequence that the change in the aforementioned reception direction takes place synchronously with the movement of the scanning beam. In the present case, this frequency ratio is achieved by deriving the modulation components from the same generator 221 both for the transmission arrangement and for the reception arrangement.

The in-phase symbol components resulting in the output circuit of the modulators 245-249 are selected and amplified by the units 251-255, then fed to the common amplifier 256, demodulated in the demodulator 257 and, after being amplified again by the low-frequency amplifier 258, the input Electrodes of the cathode ray tube 259 supplied.

The cathode ray of the tube 259 is periodically deflected by the, for example, sawtooth-shaped oscillations of the oscillation generator 260, this deflection taking place synchronously with the scanning movement of the scanning beam of the transmitting device. The delay network 261 controls this deflection so that the cathode ray always begins a deflection period when the scanning beam of the transmitting device is in the direction of the straight line connecting the antennas of the transmitting antenna group 210a, so that the center of the deflecting movement of the cathode ray is that to which the antennas of the Antenna group 210 connecting straight lines corresponds to the normal direction of the scanning beam.

Since the receiving characteristic of the receiving device changes synchronously with the movement of the scanning beam of the transmitting device, a character pulse is received every time the scanning beam hits an object in the scanned space. In the receiving device, these received pulses result in a direct voltage consisting of periodic pulses, which is amplified by the amplifier 258 and fed to the input electrodes of the cathode ray tube 259. As a result, a light spot is created on the fluorescent screen of the tube, the position of which on the path of the cathode ray on the fluorescent screen indicates the direction of the object.

Since the symbol energy needs a certain amount of time to travel from the transmitting device to the object being searched for and back to the receiving device, it is useful if the device is to work at a high scanning speed and also to clearly display objects that are far away from the device the aforementioned adjustable phase slide 237 to be provided. This causes a phase delay of the modulating characters fed to the modulators 245-249 compared to the characters fed to the antennas of the group 210a and consequently the movement of the main receiving device of the receiving device, which occurs synchronously with the scanning movement of the scanning beam of the transmitting device, lags somewhat in time. In this context it should be noted that the setting of the phase shifter 237 does not change the position of the light spot resulting in the path of the cathode ray of the tube 259, since this position only depends on the direction of arrival of the reflected symbol energy, but it influences the brightness of the light spot if it ensures that the main receiving direction of the receiving device at the moment of receiving the reflected energy coincides with that direction which the scanning beam had when it hit the object. This dependence of the brightness of the light spot on the setting of the phase shifter depending on the distance of the object being sought can be used to determine the distance of the object being sought from the amount of the adjustment of the phase shifter from its basic position required to achieve the greatest brightness of the light spot. On the other hand, it can also be expedient to change the setting of the phase shifter continuously and periodically over a certain range in order to obtain an indication of both the near and the distant objects in the scanned space during successive groups of scanning periods.

It has been established above that certain modulation components of the modulated symbols resulting in the output circuits of the modulators 25-249 only have the same phase for one reception direction. It will now be examined on the basis of FIG. 23 which modulation components are to be selected by the bandpass filters of the units 251-155 in order to achieve a change in the reception characteristics of the antenna group 210b that is synchronous with the scanning movement of the scanning beam of the antenna group 210a. Let us first consider only the three central antennas 212, 213 and 214 of antenna group 210a and assume that these are supplied with the symbols expressed by the following equations:

In this is

(Omega) (sub) 1 = 2 (Pi) (f (sub) o + f (sub) c)

(Omega) (sub) h = 2 (Pi) f (sub) h and

E is the greatest amplitude of the antenna-fed characters.

As shown in connection with the transmitting devices described earlier, the sign energy which hits the object, the direction of which is determined by the angle (alpha), is as follows: (67)

In the equation is

E '= kE, where k represents the damping factor resulting from the propagation of the character in space and , where d is the antenna spacing and (lambda) is the wavelength of the symbol applied to antenna 213.

A method for graphically solving equation (67) was given in connection with Figure 2 and it has been shown there. that the beam of the antenna group 210a scans a predetermined spatial section in the direction from the antenna fed with the symbol of the highest frequency to the antenna fed with the symbol of the lowest frequency with an angular frequency (omega) (sub) h. Under the above assumption, the scanning beam moves in the direction from the antenna 212 to the antenna 214, that is to say from right to left in FIG. 23.

Scanning devices of this type can be said to generate a scanning beam because during a short part of each scanning period the emitted symbols of all antennas at a given point in space have the same phase, but during the remaining part of the scanning period they have such phase differences that the resultant sign energy received at said point is approximately zero. At the moment in which the beam generated by the antenna array 210a hits the distant object, the phase coefficient of equation (67) is equal to zero, ie the sum of (omega) (sub) ht and 2 (Pi) a cos (alpha) must be either zero or 2 (Pi) n, where n is an integer. Then the symbol energy of all antennas is in the same phase and the symbol energy reflected by the object has the angular frequency (omega) (sub) 1.

If the receiving antenna group 210b is arranged in the vicinity of the transmitting antenna group 210a, the character reflected by the object searched for arrives at the receiving antennas also at the angle (alpha) and the character energy received by the antennas 217, 218 and 219 results from the following equations:

In these is

E '' = k'E ', where k' in turn represents the damping factor resulting from the propagation of the character in space.

Equations (68), (69) and (70) are based on the assumption that the time it takes for the symbol energy to travel the path from antenna array 210a to the object and from there back to antenna array 210b is negligible. In reality, the deviations resulting from this assumption are compensated for by the adjustable phase shifter 237, which shifts the phase of the characters fed to the character channels of the receiving antennas by an angle corresponding to the transit time of the characters.

It is now assumed that the modulators 246, 247 and 248 connected to the antennas 217 and 219 are supplied with modulating symbols expressed by the following equations:

In these equations is

E (sub) o the amplitude of the modulator symbols and

(Omega) (sub) 0 = 2 (Pi) (f (sub) o - f (sub) c).

If the intermediate frequency band filters of the units 252, 253 and 254 separate out the difference frequency components of the modulated characters resulting in the output circuits of the modulators 246, 247 and 248 and feed these combined with one another to the input circuit of the common amplifier 256, an intermediate frequency character of the following form arises:

A graphical solution of equation (74), as it was shown with reference to FIGS. 2-12, shows that the reception characteristic of antenna group 210b is a scanning movement in the direction from that antenna whose symbol channel is fed with the modulating symbol of the lowest frequency to that antenna , whose symbol channel is fed with the modulating symbol of the highest frequency, ie in the present case from the antenna 217 in the direction of the antenna 219. The direction of this scanning movement is the same as that of the scanning movement of the beam of the antenna system 210a and consequently the reception characteristics of the device are scanned scans the room synchronously with the scanning beam. It can of course be shown that this result of the above investigation also applies if all antennas are taken into account in both groups instead of the three antennas considered.

If the band filters of units 252, 253 and 254 were to select the sum frequency components of the modulated symbol, the direction of the scanning movement of the receiving characteristic would be opposite to that of the scanning movement of the scanning beam. It follows that in the event that the modulator 246 is supplied with the modulating symbol with a higher frequency and the modulator 248 with the one with a lower frequency, the band filters of the units 252, 253 and 254 must select the sum frequency components of the modulated symbol in order to ensure a synchronous movement of the To achieve reception characteristics with the scanning beam. In general, for known reasons, it is desirable that the amplifiers of the units 251-255 operate at a relatively lower frequency and it is therefore advantageous if the modulators 245-249 are supplied with the modulating symbols in such an order that the difference Frequency components can be selected and used, since their frequency is considerably lower than that of the characters broadcast by the antennas 211-215.

In the case of the present exemplary embodiment, the frequency f (sub) o of the superimposed oscillation generator 244 of the receiving device was chosen, for the sake of simplicity, to be the same as that of the superimposed oscillation generator 238 of the transmitting device, but the two mentioned oscillation generators can of course also work with different frequencies. The only requirement with regard to the oscillator 244 is that its operating frequency must be suitable for generating such intermediate frequency symbols to which the amplifiers of the units 251-155 and 256 are tuned. It should also be pointed out that the separation of the transmitting and receiving antennas used in the present exemplary embodiment is by no means absolutely necessary; rather, the same antennas can be used for both purposes at the same time if only separate character channels are provided for sending and receiving. However, in this case it is advisable to provide transmission lines of suitable length between the units 231-235 and the antennas, and between the antennas and the units 245-249. In this case, pulse modulation is expediently used in the transmission device.

From the above description of the arrangement according to FIG. 22 it follows that the generators 221 and 222, the balanced modulator 223 and the band filter modulator unit 224 have means for generating a plurality of carrier characters with the mutual spatial distances of the transmitting antennas 221-215 proportionally different frequencies represent, while the generators 221 and 222 the balanced modulator 236 the bandpass filter modulator unit

238 and the modulators 245-249 represent means for modulating the reflected characters received by the individual receiving antennas with modulating characters, the frequencies of which on the one hand differ from that of the emitted characters and on the other hand are proportionally different under the mutual spatial distances of the receiving antennas 216-220 in this way to obtain modulated characters which each have the same phase for a specific receiving direction which changes synchronously with the scanning movement of the emitted beam. If the antennas are arranged at the same intervals, the frequencies of the transmitted carrier symbols and the symbols modulating the received symbols also have the same mutual spacing in the frequency band. Furthermore, it follows from the above description and in particular from equations (67) and (74) that the sampling period of the transmission and reception characteristics corresponds to the fundamental frequency (omega) (sub) h and the harmonic 2 (omega) (sub) h the oscillation generated by the generator 221 changes, so it can be easily and conveniently regulated by changing these frequencies. Such a regulation naturally requires a corresponding change in the tuning of the band filters of the units 225-229 and 239-243, which can optionally be effected by means of equal control means. The shape of the directional characteristics and in particular the ratio of the size of the main radiation or the main sensitivity to the size of the secondary radiation or the secondary sensitivity changes with the amplitude ratio of the emitted characters or the characters modulating the received carrier characters and can therefore be changed by changing the gain of the amplifiers of the units 231 -235 or 239-243.

For certain purposes it may be desirable to provide a device according to FIG. 22 suitable for scanning in two directions normal to one another. This can be achieved simply by using two such devices, the antennas of which are arranged along straight lines that are normal to one another. In this case it is advantageous if the scanning speed of the two devices is different so that the output character of the additional device can be fed to an additional pair of deflection electrodes on the first pair. In this way, a pattern of parallel scanning lines is produced on the fluorescent screen of the tube and the received, reflected symbol energy generates two mutually mutually perpendicular lines on the fluorescent screen, the intersection of which indicates the location of the object sought in two dimensions.

24 shows an embodiment of a combined transmitting and receiving device, which is essentially the same as that according to FIG , modulating characters serving received carrier characters is supplied by the band filter modulator unit 224 of the transmitting unit.

As a result of the even number of antennas in each antenna group, there is no middle antenna, but there is a point in each antenna group, which can be viewed as the center of the group and the frequency components <Formula> and <Formula> of the modulation symbol supplied by the generator 221 ' therefore have the distance between the individual antennas in the frequency band, in the middle between antennas 213 and 214 or 218 and 219 located center of the antenna group are proportional to mutual distances. The balanced modulator 223 ′ is connected in such a way that it suppresses the carrier wave of the generator 222. The use of an additional antenna 265 in the antenna array 210a 'naturally requires the use of an additional bandpass filter modulator unit 263 and an additional bandpass filter amplifier unit 264 in order to supply the corresponding symbols to this antenna.

The sum frequency components <Formula> to <Formula> resulting in the output circuits of the bandpass filter modulator unit 224 'were fed to the transmitting antennas 211'-215' and 265 in the same way as in the device according to FIG. The simultaneously resulting difference frequency components <Formula> to <Formula> have those values which are required for modulating the received carrier characters in the modulators 245'-249 'and 267 and are therefore fed to these modulators in such a way that the frequencies rise in the opposite direction as in the sending facility. This type of generation of the modulating characters for the receiving device has the advantage that it greatly simplifies the receiving device by making the phase shifter 237, the balanced modulator 236 and the band filter modulator unit 138 of the device according to FIG. 22 superfluous. However, very high scanning speeds cannot be used here, since the device has no means of taking into account the transit time of the characters from the device to the reflective object and back to the device.

For the purpose of coupling the output circuit of the modulator unit 267 to the common intermediate frequency amplifier 256, an additional intermediate frequency band filter amplifier unit 268 is provided. seen.

The mode of operation of the device according to FIG. 24 is essentially the same as that of the device of FIG. 22. The frequencies of the characters supplied to the character channels of the individual antennas are based on the prerequisite that the antennas in both antenna groups are arranged at the same distance.

FIG. 25 schematically shows part of a combined transmitting and receiving device, which differs from the device according to FIG. 22 only in that the antenna 218, the associated modulator 247 and amplifier 253, and the band filter modulator 241 of the unit 236 '' is omitted. Antenna group 210a therefore consists of five antennas, antenna group 210b ″, on the other hand, has only four antennas, the spatial distance between antennas 217 and 219 being twice as great as that between antennas 216 and 217 or 219 and 220 the gain of the amplifier of unit 233 is 2.25 times that of the amplifiers of units 231, 232, 234 and 235, for reasons to be explained below.

The mode of operation of the device according to FIG. 25 is essentially the same as that of the invention of FIG. 22, with the difference that the antenna group 210a has secondary radiation falling between the secondary sensitivity ranges in the reception characteristics of the antenna group 210b ″. The excitation of the antenna 213 of the antenna group 210a with characters, the amplitude of which is 2.25 times the amplitude of the characters exciting the other antennas of this group, has the effect that two undesired secondary radiation from the antenna group 210a of the device according to FIG. 22 is suppressed . The directional characteristic of the antenna group 210a excited in this way results in accordance with equation (67) for the antenna group 210a in FIG. 22 as follows:

The solid lines A, B and C in FIG. 26 show the directional characteristic of the antenna group 210a in FIG. 25 at three selected points in time of a sampling period, namely for the values of <formula>. These curves were found by solving equation (75) graphically in accordance with Figs. 2-12.

The intermediate-frequency character that arises in the common output circuit of the bandpass filter amplifier units 251, 252, 254 and 255 results from a similar analysis to:

The graphical solution of this equation results in the dashed curves D, E and F of FIG. 26, which represent the reception directional characteristic of the antenna group 210b ″ for the aforementioned values of (Omega) (sub) ht.

26 shows that at those times at which the secondary radiation from the antenna group 210a result in an undesired reflection of symbols by the object being sought, the reception sensitivity of the antenna group 210b ″ in the relevant direction is zero. The device according to FIG. 25 thus has the important advantage that only the main beam of the antenna group 210a provides a display on the display device, so that this display is completely unambiguous.

The devices according to FIGS. 22-25 are particularly suitable for operation with pulse modulation. In this type of operation, the character originating from the generator 222 or 222 'is amplitude modulated with recurring pulses, the duration of which is short compared to the period of each recurrence. This modulation can either be carried out in the generator itself or in a modulator stage following the generator. The receiving device can then either be operated with constant sensitivity, or the modulating voltage pulses can be fed to the gain-regulating circuit of the receiving device, e.g. the corresponding circuit of the amplifier 258 in order to periodically change the sensitivity of the receiving device.

Claims (24)

1. Device for scanning a room at the transmitting or receiving end by means of a fixed group of antennas, in which the antennas are arranged in a row with distances between the rows and between the antennas in each row, characterized in that each antenna is connected to a signal channel that each Symbol channel is fed with symbols of constant frequency, and that the symbols fed to the various channels have different frequencies which increase proportionally to the antenna stock from one end of each antenna row to the other end of the row, with a continuous rotation of the directional characteristic due to the alternating mutual phase designations of the antenna system comes about. 2. Device according to claim 1, in which the antennas are arranged in several rows, characterized in that the frequencies of the characters which are fed to the channels of two adjacent antennas of each individual row differ by a different amount than the frequencies of the characters, which are fed to the channels of those antennas which are in adjacent rows and at equal distances from one end of the row. 3. Device according to claim 2, characterized in that the frequencies of the characters which are fed to the channels of the antennas of the individual antenna rows are proportional to the distances between the rows from the one outermost row rise towards the other outermost row. 4. Device according to one of claims 1 or 2, characterized in that a common high-frequency generator feeds the channels of all antennas and is modulated in such a way that modulation components of different frequencies result for each channel. 5. Device according to claim 4, with one or more rows of antennas consisting of an odd number of antennas, characterized in that the carrier component of the modulated oscillation generated by the common character generator is fed to the character channel of the central antennas of each row, while the modulation components of the upper modulation sideband are the Character channels on one side of the central antenna located antennas and the modulation components of the lower modulation sideband are fed to the character channels of the antennas located on the other side of the central antenna. 6. Device according to claim 4, with one or more antenna rows consisting of an even number of antennas, characterized in that the carrier component of the modulated oscillation generated by the common character generator is suppressed and the modulation components of the upper modulation sideband the character channels on one side from the center of the Antennas located in rows and the modulation components of the lower modulation sideband are fed to the character channels of the antennas located on the other side of the center of the antenna rows. 7. Device according to claim 4, characterized by means for repeated modulation of the oscillation of the common character generator with oscillations of different frequencies. 8. Device according to claim 7, characterized in that the character channels of the antenna rows located on one side of the center of the antenna field with the oscillations resulting from the second modulation of the modulation components of the upper sideband of the first modulation and the character channels of the antennas on the other The rows of antennas located on the side of the center of the antenna field are fed with the oscillations resulting from the second modulation of the modulation components of the lower sideband of the first modulation, with the oscillations fed to the character channels of the antennas on one side from the center of each row of antennas from the modulation components of the upper Sideband of the second modulation and the oscillations fed to the character channels of the antennas located on the other side from the center of each antenna row consist of the modulation components of the lower sideband of the second modulation. 9. Device according to one or more of claims 4-8, characterized by means for setting the frequency ratio of the characters fed to the character channels of the individual antennas. 10. Device according to one or more of claims 4-9, characterized by means for separately setting the frequency of the oscillations of the carrier character generator and the frequencies of the modulating oscillations. 11. Device according to one or more of the preceding claims, characterized by means for feeding the antenna with the preferably pulse-modulated carrier characters of different frequencies supplied to its character channels, whereby scanning of a room with a carrier character beam is achieved. 12. Device according to one or more of claims 1-10, for scanning a room by means of directional reception of the carrier characters sent or reflected by an object located in the room, characterized in that the characters supplied to the antenna's character channels are of different frequencies for modulating the antenna's received carrier characters are used, wherein means are provided to select those modulation components of the carrier characters modulated in this way and to combine them with one another which are in phase only for a receiving direction which changes continuously and periodically over a given angular range. 13. Device according to claim 12, with a cathode ray tube, as an indicator member, characterized by means for controlling the cathode ray of this tube through the modulation components resulting from the modulation of the received characters and means for synchronously with the change in the resulting from the combination of said modulation components Receiving directional characteristic taking place deflection of the cathode ray. 14. Device according to claim 13, characterized by means for generating preferably sawtooth-shaped deflection voltages for deflecting the cathode ray and for synchronizing these voltages by the modulating the emp- Modulating characters used for catching reflected characters. 15. Device according to claim 14, characterized by means for generating the deflection voltage in such a way that the individual scanning periods of the cathode ray begin at the times in which the direction of the highest reception sensitivity resulting from the combination of the modulation components of the received reflected characters has the smallest angle with the straight line connecting the antennas. 16. Device according to claim 14, characterized by means for delaying the synchronized movement of the cathode ray according to the time difference between the emission of the character and the reception of the reflected character. 17. Device according to one or more of claims 1-10, for determining the location of an emitted symbol reflecting object in space, characterized by means for generating a symbol beam executing a periodic scanning movement by supplying symbols of a predetermined frequency to at least one of the antennas and symbols a different frequency to at least one other antenna, means for modulating the symbol reflected by the searched object and received by an antenna with a modulating symbol, the frequency of which is different from that of the symbol transmitted to the first-mentioned one antenna, and for modulating the symbol transmitted by the searched object reflected symbol received by another antenna with a modulating symbol whose frequency differs from the Frequency of the transmitted character fed to the first-mentioned other antenna differs in such a way that modulation components result from the modulation of the received characters which are only in phase for a receiving direction that changes synchronously with the scanning movement of the transmitted character beam, as well as means for combining these modulation components. 18. Device according to claim 17, characterized in that the frequency difference between the modulating symbols used to modulate the reflected symbols received by any pair of adjacent receiving antennas is at least equal to the frequency difference between the symbols supplied to any pair of neighboring transmitting antennas. 19. Apparatus according to claim 18, characterized in that the frequency difference between the modulating symbols used to modulate the reflected symbols received by any pair of adjacent receiving antennas is twice the frequency difference between the symbols supplied to any pair of neighboring transmitting antennas. 20. Device according to one or more of claims 17-19, characterized in that the row of receiving antennas is perpendicular to the row of transmitting antennas. 21. Device according to one or more of claims 17-20, characterized in that at least one of the transmitting antennas is excited with greater energy than the others and the receiving means, which in their position would correspond to transmitting means connected to this antenna, are omitted. 22. Device according to one or more of claims 17-21, characterized by a common carrier character generator for generating all emitted characters and modulating characters, as well as means for modulating the vibrations of this generator in such a way that a group of modulation components of different frequencies to be fed to the individual transmitting antennas and another group of modulation components of different frequencies suitable for modulating the received reflected characters are created . 23. Device according to claim 22, in which the modulated oscillations generated by the common carrier character generator are converted into a higher frequency position, characterized in that the modulation components of the upper frequency band resulting from the conversion are fed to the transmitting antennas and those of the lower sideband are reflected to modulate the received ones Characters are used. 24. Device according to one of claims 22-23, characterized by means for shifting the phase of the characters used to modulate the received reflected characters in relation to the phase of the emitted characters.