SU20152A1 - Method of radiotelephone transmission - Google Patents

Description

In existing radiotelegraph or radiotelephone devices, modulation is carried out in such a way that the amplitudes of the carrier wave are affected by sound frequencies, as a result of which, besides the fundamental frequency, there are two more bands, so. called sidebands. Upon detection of a carrier beating with side frequencies, the modulating frequencies are reproduced in the receiver. The need to receive these 6oKOBbjx bands is due to the fact that the entire amplifying part, the antenna system and other station aggregates have to design the calculation short circuit not at the average power of the station, but at the instantaneous maximum power value that occurs when the amplitude of the carrier wave is added modulation.

The present invention aims to facilitate the design tasks and reduce the power of individual units by implementing separate amplification - or separate amplification and transmission of carrier and side frequencies.

The essence of this method is as follows. The average transmitter power can be determined by the formula

R.P. -1 + 2 (

where P is the average power, PO is the power of the carrier wave, and F is the modulus of modulus. At the same time, the instantaneous power occurring at the moment of maximum will be Pi (- {- Ж) 2. Thus, with a modulation factor of 70%, the average power is only 20% higher than the power of the carrier wave, while the maximum instantaneous power is much higher than the power of the carrier wave. This is due to the fact that the power increases in proportion to the square of the amplitude, and at the moment when the amplitudes of both side frequencies and the carrier wave add up, the amplitude increases to a very large magnitude. The same circumstance makes it extremely difficult to construct antennas, which, as is well known, must be designed for maximum M1 power. Meanwhile

If, in accordance with the present invention, the power of the carrier wave and the bobbin frequencies are allocated to different devices, then instead of one there will be essentially two or three transmitters capable of working simultaneously on different antennas, and the power of the carrier wave will be constant, and the power of the side waves frequencies will be variable depending on the modulation depth at any given moment. Then in the maximum case of separate transmission of all frequency bands w, w-4-K „M, w - J ,, R you must have three stations, of which one has a power of 1

ness ma, and two other capacities; I „1

each, or, if you connect both side frequencies in one transmitter, you will get two transmitters: one, still giving only the carrier wave, and the second,

giving both sides with a power of 2 P; (j.

Such a device should, first, lead to a cheaper main antenna, which in this case, with a modulation depth of 70 / o, will have to carry three times less power; secondly, saving of lamps must be obtained, since the lamp set must be counted on maximum power, and with a modulation depth of 70 / o, the nominal power of the lamps must be at least three times greater than the nominal power of the station. Further, at very powerful stations, the use of a lamp generator already raises some doubts in the sense of its tenoco6HOCTH competing with a high-frequency machine. The main difficulty in applying a high frequency machine is, firstly, the modulation system itself and, secondly, the difficulties encountered in stabilizing the machine in alternating mode. The latter can be equally applied both to the telephone and to the telegraph. Meanwhile, in this case, to create a constant source of carrier wave, the modulation

machines, as well as the adoption of any special measures to paralyze the destabilizing factors on the load side. The load remains constant and the machine can be stabilized, working in the most favorable mode / devoid of any violations. This may give the machine an advantage over the tube generator in the sense of simplification when using large powers.

The subject of the patent.

1. A radiotelephone transmission method, especially for broadcasting purposes, characterized in that the sidebands resulting from modulation, either directly or after a preliminary amplification, are separated from the carrier frequency and amplified by separate amplifying steps, after which they are radiated together with the unmodulated carrier frequency.

2. In the method described in Section 1, the use of separate amplification of both side frequency bands.

3. Acceptance of the method described in p. 1, 2, characterized in that separately amplified frequencies or frequency bands are transmitted to individual antennas.

4. When described in pp. 1, 2, the method of applying a common master oscillator and devices for the separation of frequencies or frequency bands isn.

5. In the method described in Section 4, the use of separate master clock synchronizers for all three frequencies or for the carrier frequency and both side frequencies,

6.With the method described: in p. 4 and 5, used as a high-frequency carrier frequency generator.

7. With the method described in p. 1-6, applying modulation at a frequency lower than the final frequencies.