Reflex klystron oscillators forex
Wax nostalgic about and learn from the reflex klystron oscillators forex of early electronics. Television News, published 1919 – 1959. See those pics and his note below. Practical operating data on klystrons as used in present-day communications equipment.
Microwave frequencies are being used to an ever-increasing degree in commercial television and communications links, amateur transmission, and a long list of governmental and industrial electronic devices such as radar, instrument landing, guided missiles, and air traffic control. Consequently, the field of microwave techniques offers an excellent opportunity to technicians and engineers, as well as providing interesting equipment for ham operation. 5 is a block diagram of a typical transmitter and receiver operating at microwave frequencies. As seen in this diagram, all stages except the microwave oscillator in the transmitter and input circuit and local oscillator in the receiver, operate at conventional frequencies. 5 – Block diagram of a conventional microwave transmitter and receiver.
There are a number of methods of generating energy at microwave frequencies including lighthouse oscillators, magnetrons, traveling wave tubes, and klystrons. The klystron oscillator, which is the subject matter of this article, is by far the most commonly used oscillator, particularly in commercial equipment. Sylvania’s reflex klystron is designed to operate at wavelengths be tween 6-7 cm. For reasons that need not be discussed in this article, it is extremely difficult and inefficient to generate microwave energy using conventional techniques and tubes. Of the microwave oscillators listed, only the lighthouse tube uses standard oscillator circuits.
This type of oscillator, however, has an upper frequency of about 4000 mc. All of the other oscillators, sometimes called transit time oscillators, employ new and different techniques of oscillation. Since entirely new techniques are involved, the authors have divided this article into two parts. The first part describes the basic theory of klystron operation so that a reader who has never had any previous microwave experience can understand how it works. 1 – Electron flow in a diode tube. A very familiar universal law – conservation of energy – which is rarely used in electronic theory becomes very important in klystron and other transit time oscillator operation.
They are called transit time oscillators because the energy required to sustain oscillations is obtained from the electron stream while it is in transit between cathode, or electron gun, to plate, or collector. Consider the flow of an electron that leaves the cathode of the diode, shown in Fig. 1, and travels toward the plate. When the plate is positive with respect to the cathode, the electron is accelerated toward the plate.