Radio electronics in space

The formula “radio + electronics = radio electronics “provides us with a good example of fruitful cooperation. To work successfully in any field of science now means to know the fundamentals of radio electronics. A physician has to know the properties of high frequency currents, a mathematician – the properties of fast-acting computers, an astronomer – the properties of radio telescopes, a physicist – the properties of charged particles. Without radio electronics it is impossible to develop cybernetics, astronautics and nuclear physics. Much attention is now given to the frequency stability of generators – the heat of all radio transmitting systems. To establish reliable contact with Mars, the frequency control must be within billionths of a per cent. The role of “electrical pendulum “which sets the frequency of oscillations in highly stable generators is performed by a plate of crystalline, quartz. Like the string of a mystical instrument, this plate can be tuned to a definite frequency. The thinner the plate, the higher the frequency is. The thinnest plates give a frequency of scores of mcps (millions of oscillations per second). The super high frequencies used in cosmic communication are of hundreds and thousands of mcps. To use special multipliers means to active such frequencies. Ordinarily it is a chain of valve or transistor stages, each containing a score of parts. This increases the size of equipment, requires more power and results in reduced reliability. To solve the problem of high frequencies another way out has been found. The oscillations of quartz may be induced not on the main frequency, but on its harmonic overtones. One of the biggest problems is to “tame” overtones in transistor generators, that is where they are most necessary. The frequency “ceiling” for them is usually 100 mcps. The generator used, for instance, in the instrumentation of the US artificial Earth satellites “Vanguard “and “Explorer “, had a frequency of 108 mcps (millions of cycles –мегагерц = 10 гц – per second).

Date: 2015-09-02; view: 391; Нарушение авторских прав