DE641365C - DF receiver for directing aircraft using the dot-dash method - Google Patents

Description

GERMAN EMPIRE

ISSUED ON
JANUARY 25, 1937

. REICH PATENT OFFICE

PATENT LETTERING

CLASS 21 a 4 GROUP 48

Patented in the German Empire on June 5, 1934

The present invention relates to a sighting device for use in procedures where a guideline is preferred modulated signals are emitted at an angle to each other, in particular the use of a cross-coil instrument for visual display of the signals in the direction finder according to the invention.

Directional transmitters are installed at airports and air routes to secure air traffic set up in two at a certain angle between the main ray axes radiate in lying directions. , The line of equal field strength, the so-called guideline, is used to mark the traffic route. In order to be able to recognize lateral deviations from the guideline, received two associated radiations each have different identifiers, e.g. B. complementary Characters that merge into a continuous line on the guideline.

In the past, acoustic display methods were predominantly used to receive such direction finding transmitters used. The disadvantage of this method is that the amplitude differences the signs must be perceived as volume differences with the ear. But the ear has the peculiarity Perceive volume differences as such only with relatively large amplitude differences to be able to.

It has therefore been proposed to use an optical display device instead of the audio reception to kick. For this purpose, after the rectification of the received high frequency the low-frequency modulation can be rectified once more to achieve the To be able to make signals visible with a pointer instrument. To solve this problem it has been suggested to set the operating point of the relevant rectifier tube in to lay the area of the lower curve bend. That way you get at one Moving-coil instrument lying directly in the anode circle 'jerks that correspond to the size correspond to the various signals. These methods have the disadvantage that when approached to the sender while observing the guideline, i.e. if the two page IDs are the same, the resulting permanent 50 Rash with decreasing distance from transmitter to receiver grows and vice versa. ' In other words, the one that characterizes the guideline The deflection is not constant and the pilot has to use the instrument for a long time watch to see if the major rash is preponderant Side signs or from the increasing reception field strength.

The present invention aims, on the one hand, that if the guideline is observed the scale of the Alizeigeinstrument always a constant value, z. B. the one in the middle of the Zero point lying on the scale (with negative and positive scale graduation), is displayed, regardless whether the total field strength at the location of the vehicle is large or small. On the other hand, the present invention

*) Your patent seeker stated as the inventor:

Rudolf Weher in Berlin.

can be achieved that if there is a deviation from the guideline, the pointer of the indicating instrument always only points to one side _; beats and thereby executes as strong a deflection as possible towards the half of the scale assigned to the side of the deviation. ₁

the pointer "of the instrument should return to zero without the fading of a character to commute to the other side of the scale beforehand. ίο By means of the direction finder according to the invention, which was developed primarily for use in a dot-and-dash process all requirements to be placed on a display device are met. The inventive DF receiver with visual display instrument, in which after the rectification of the received vibrations pulsating DC voltages arise or, in the case of modulated signals, the modulation oscillations rectified in a further straightening stage is characterized by that the mean DC value of the rectifier output is filtered out and the im Clock of the signals occurring pulsations (alternating current impulses) a cross-coil instrument are fed, whose two coils each have a rectifier, but with opposite one Passage directions, is connected upstream.

The filtering out of the mean DC value from the rectifier output is done by a resistance capacitance combination, namely in the form that the rectified voltages of a combination consisting of capacitor C ₁ and resistor R _{1 are} fed over the pulsations occurring at the resistor ^ in the cycle of the signals a large capacitor C ₂ can be fed to the display instrument.

The mode of operation of the direction finder according to the invention is to be exemplified with reference to FIG Fig. Ι to 3 are explained, provided that modulated by the master transmitter Characters are sent using the e / t method (dot-dash).

+5 In Fig. Ι, Mf is the low frequency output tube of any DF receiver. In the anode circuit of this tube is the output transformer T _n, which is intended to keep the anode DC voltage away from the subsequent arrangement and at the same time can serve to adjust the resistance of the connected elements. The alternating voltage U _N f (see Fig. 2a or 3a) appearing at the terminals A> B of _{the transformer is rectified by a rectifier Q 0} and fed to a combination of resistor ^ ₁ and capacitor C _1. This combination should have a time constant that is small compared to the duration of the shortest character that occurs, so that the short characters cannot be blurred. On the Klem

With the resistance ^ ₁ tensions occur, for example of the shape corresponding to .bb. 2b 'and 3b. If the current component of these pulsating chips is eliminated by a large capacitor C _{2 , 2} pulsations U _R2 of the form shown in FIGS. 2c and 3c occur at a subsequent resistor The direct current component can also be eliminated using a suitable transformer, but with the slow pulsations to be transmitted this would be very large and therefore difficult and expensive.

Another object of the invention is the training and the circuit of a cross-coil instrument Ιζ. The cross-coil instrument K ₁ has two coils S 1 and S ₂ , which are crossed to one another at a suitable angle and are preferably arranged one above the other on an axis to avoid a mutual induction effect. The zero point O lies in the middle of the scale P. The magnet M is designed in such a way that the flux of force acting on the individual coils is not homogeneous for all coil positions. The magnet M can therefore, for. B. have a particularly large air gap or the hole within which the coils rotate can have an elliptical cross section. The purpose of this formation of the magnetic field is that, on the one hand, the current-carrying coil is drawn into a homogeneous field that is as strong as possible and can then exert a corresponding torque, and on the other hand, the current-free coil is rotated into a field that is as weak as possible so that it does not have any significant counter- EMF can develop at their ends. In this way, an extremely low setting attenuation is achieved.

The coils S ₁ and S _{2 of} the cross-coil instrument K. are on one side with the junction of the resistors R ₁ and R ₂ and on the other side with the interposition of a rectifier G ₁ and G ₂ with mutually opposite conduction direction with the Junction point of the resistor R ₁₂ and the capacitor C ₂ connected.

To understand how this arrangement works, think again of the alternating voltage shown in Fig. 2c. The high positive voltage corresponding to the dot symbol flows through the rectifier G ₁ and gives the coil S ₁ a strong deflection. This should rotate in such a way that it remains in the strong homogeneous field, for example in such a way that the pointer deflects to the left as shown in Fig. Ι.

At the same time, the coil S _{2 is rotated} out of the dead field. When changing to the line symbol (negative voltage), the current flows through G _{2 and thus through the coil S 2,} which is currently in a relatively weak field *. The torque developed by S ₂ is low. Almost only the spring acts as a restoring force. In order to now have a high level of damping during the reverse rotation

To generate ίο, a further rectifier G ₃ or G ₄ with corresponding setting resistors r ₃ and / * _{4 is placed in} parallel with the coil that has been turned back without current. It is thus achieved that the EMF occurring at the ends of the reversed coil ₁ equalizes over the circle S ₁ , G ₃ and r _r depending on the size of the circle constant and the return attenuation increases considerably. The return damping can be set as required _{by the resistors r 3} and ^ _4.

By the circuit according to the invention

it is achieved that the adjustment damping for the predominant character is low and the restoring damping is large. With the direction finder according to the invention it is possible ^{to display the lateral deviation of an aircraft from the 1} guideline by means of an exact one-sided deflection.

In one implemented device, junction rectifiers have proven particularly useful. Switching elements of the following sizes were used in the same device:

C ₁ = 4 fiF,
R ₁ = ίο · 'Olim,
C ₂ = 300 (aF.

The direction finding device according to the invention can also be used without further ado in those cases in which unmodulated characters are transmitted by the guide transmitter. A receiver in this regard would be constructed as follows, for example: An intermediate frequency amplifier would be arranged in a row on the receiving or mixing tube, the output energy of which would be rectified in a subsequent high-frequency detector. The directional voltage of this high-frequency detector would then be fed to a combination, consisting of capacitor C ₁ and resistor R ₁ , and the pulsations occurring at resistor ^ ₁ via a large capacitor C _{z to} the cross-coil instrument.

A low frequency amplifier and 'another Rectifiers for the modulation frequency would then be omitted.

Claims (8)

Patent claims: 1. DF receiver for directing aircraft according to the dot-and-dash method 6b with a visual display instrument, after which the received vibrations have been rectified pulsating DC voltages arise or, in the case of modulated signals, the modulation oscillations in a further straightening stage are rectified, characterized in that for Preservation of fluctuations in the display instrument, the mean DC value of the rectifier output is filtered out and the pulsations occurring in the cycle of the signals to a cross-coil instrument are fed, the two coils of which each have a rectifier, but with opposite one Passage directions, is connected upstream. 2. Peügerät according to claim 1, characterized in that the two coils of the cross-coil instrument further rectifiers are connected in parallel. 3. Peügerät according to claim 1, characterized gekennzeicKnet that in series with the parallel connected ¹ rectifier is a variable resistor. 4. direction finder according to claim 1, characterized in that the rectifier junction rectifier be used. 5. Cross-coil instrument for use in a Peügerät according to claim 1, characterized characterized in that the magnetic field penetrating the coils is not due to the appropriate shaping of the air gap is constant in all coil positions. 6. Cross-coil instrument for use in a Peügerät according to claim 1 and following, characterized in that " the zero point of the scale is in the center of the display device. 7. Peüempfangsgerät according to claim 1, characterized in that the direct current mean value of the rectifier output is screened out by a resistance capacitance combination, such that the rectified voltages of a combination consisting of capacitor (C ₁ ) 'and resistor (^ ₁ ), supplied and the Pulsations occurring at the resistor in time with the signals are fed to the display device _{via a large capacitor (C 2).} 8. Peügerät according to claim 7, characterized in that the time constant of the combination (C ₁ , R ₁ ) is small compared to the duration of the shortest signal. 1 sheet of drawings