US2281982A

US2281982A - Arrangement for transmitting and receiving wireless messages

Info

Publication number: US2281982A
Application number: US359852A
Authority: US
Inventors: Leyn Albrecht
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1939-07-05
Filing date: 1940-10-05
Publication date: 1942-05-05
Anticipated expiration: 1959-05-05

Description

May 5, 1942. A. LEYN 2,281,982 ARRANGEMENT FOR TRANSMITTING AND RECEIVING WIRELESS MESSAGES Filed 001;. 5, 1940 4' 7 Yifffii I I l v l l AAHHAQER CUNVPO 6000kC I 600m 1 w m I I .l I L REC'E/VER INVENTOR ALBAFCHT LEYN ATTORNEY Patented May 5, 1942 ARRANGEMENT FOR TRANSMITTING AND RECEIVING WIRELESS MESSAGES Albrecht Leyn, Berlin, Germany,

funken Gesellschaft fiir Drahtlose assignor to Tele- Telegraphic Zehlendorf, Osteweg, Berlin, Germany, a corporation of Germany Application October 5, 1940, Serial No. 359,852 In Germany July 5, 1939 7 Claims.

The technical problem exists so to build a transmitter and receiver that the transmitter and receiver operate on the same wave frequency, whereby the transmitter shall not contain a selfexcited generator, but the local oscillator provided at the receiver side shall be employed at the same time for controlling the frequency of operation of the transmitter stages. This problem presents itself in part in view of the fact that the provision of oscillators having an absolutely constant frequency involves a very complicated ensemble especially in the case of extremely short waves. The local oscillator of the receiver must have a constant frequency and, therefore, the question arose as to whether it may be possible to utilize in any suitable way the heterodyning oscillation for controlling the transmitter. Since, in accordance with the problem set, the transmitter oscillation is to be equal to the receiving oscillation, it is obvious that the heterodyning frequency cannot be used unchanged as control frequency and it is here where the present invention sets in. The receiver contains an intermediate-frequency stage whose frequency corresponds with the difference of the frequencies of the arriving wave and of the heterodyning oscillation. This intermediatefrequency stage now may be provided with a feedback whereby it can also operate as generator, namely for the intermediate frequency. Such a generator can be made to operate at constant frequency in a much simpler way than a generator for shorter waves inasmuch as the intermediate-frequency stage is arranged from oscillatory circuits having a favorable constancy of frequency of operation. Now, in order to control the transmitter, the heterodyning oscillation is combined with the oscillation of the intermediate-frequency stage which operates as a generator. As can easily be seen, the sum wave furnishes the transmitting frequency. This sum wave is then applied to the transmission aggregate whereby the transmitter stage is controlled. The present invention will now be elucidated in reference to the accompanying drawing.

In the drawing, the circuits in the rectangle E is the receiver, those in the rectangle S is the transmitter. The transmitter structure comprises an amplification stage V and a control stage St. The receiver has a high-frequency amplifier stage II, a local oscillator stage U and an intermediate-frequency stage Z. Keying or modulation of the transmitted wave may occur in stage V or St. The drawing shows that the intermediate-frequency stage contains a feedback connection R which can be actuated by a key T. The receiver output may be derived in stage Z. Furthermore, a mixer stage M is provided connected to U and Z and to V by way of St. Assuming the transmitter wave and the receiving wave have a frequency of 6000 kilocycles and that the local oscillator U produces a frequency of 5900 kilocycles, then an intermediate frequency of kilocycles will be obtained. If the feedback is operated, the intermediate-frequency stage oscillates in the frequency 100 kilocycles. These oscillations together with the 0scillations of the local oscillator U are applied to the mixer tube M and furnish again the output oscillation of 6000 kilocycles which, as is indicated by the connection, is applied to the control transmitter St. With this arrangement a short wave oscillator having constant frequency can be dispensed with. That is, the stage Z operating at a lower frequency can be readily stabilized as to frequency of operation. Aside from the fact that the intermediate frequency stage, if it operates as a generator, can be more readily adapted for constant frequency than an oscillator for short waves, variations of the intermediate frequency, especially in respect to the transmitter frequency to be produced, play but an unimportant part. The arrrangement according to the present invention, can be employed for telegraphic operation as well as for telephonic operation. In case of the telegraphic operation in order to give the signals it is sufficient to operate the key T which connects and disconnects the feedback, while in the case of telephonic operation, it is obvious that during the entire time of speaking the said key must be closed, i. e., to provide feedback and cause the oscillator to oscillate. It is obvious that the various modes of construction may greatly differ from one another. It'is likewise obvious that in a manner known as such further amplifier stages and relays may be provided.

What is claimed is:

1. In a signalling system, receiving means including an amplifier for receiving and amplifying signalling energy of a first frequency, an oscillation generator for producing wave energy of a second substantially fixed frequency, a mixing circuit and intermediate frequency stage coupled to both of the aforesaid means for beating said wave energies to produce signalling energy of a third frequency, and transmitting means including means for generating oscillations of said third frequency in said intermediate frequency stage, a detector coupled to said oscillation generator and said intermediate frequency stage for beating said generated oscilaltions of said third frequency with wave energy of said second frequency to produce wave energy of said first frequency and an amplifier and a wave energy radiator coupled to said second detector.

2. A system as recited in claim 1 including means coupled with said intermediate frequency stage when operated as a generator for modulating the wave energy of said third frequency.

3. In a transmitter and receiver, a first aerial for translating radiant energy into electrical currents, a second aerial for translating electrical currents into radiant energy, a source of oscillations, a wave mixer and intermediate frequency stage coupled to said first aerial and to said source of oscillations, a circuit for producing regeneration in said intermediate frequency stage, a second wave mixer coupled to said second aerial, a coupling between said second wave mixer and said intermediate frequency stage, and a second-separate coupling between said second wave mixer and said source of oscillations.

4. A system as recited in claim 3 including wave modulating means in the coupling between said second aerial and said second wave mixer.

5. A system as recited in claim 3 including means connected with said intermediate frequency stage for modulating the generated wave energy in accordance with signals.

6. A system as recited in claim 3 including wave amplifying means and wave modulating means in the coupling between said second named aerial and said second wave mixer for modulating the electrical currents translated by said second aerial in accordance with signals.

7. In a signalling system, a wave receiver including a stable source of oscillations and a wave converter cooperating to provide beat energy modulated in accordance with received signals, a beat frequency stage for said beat frequency, and means for providing a carrier of the frequency of said received signals for transmission purposes including means for operating said beat frequency stage as an oscillation generator and a wave frequency converter coupled to said stable source of oscillations and to said intermediate frequency stage to provide said carrier.

ALBRECHT LEYN.