JPH05315864A - Traveling wave tube amplifier - Google Patents

Abstract

PURPOSE:To reduce a heat load of a collector by detecting a traveling wave tube high frequency input level and feeding back the detected level to a control power supply being a component of a final stage collector power supply so as to control a collector voltage. CONSTITUTION:A control power supply 24 is connected to a collector terminal 20 of a 2nd collector in a power supply 2A. Moreover, an input level detection circuit 30 connects to an input circuit 28 of a traveling wave tube 1 and its detection signal is fed back to the control power supply 24. Thus, the final stage collector voltage is controlled in matching with the high frequency input level. The energy of the electron beam made incident in the final stage collector is least at saturation output and the energy is increased in matching with the reduction of the high frequency input level, then the heat load of the collector is reduced without losing the electron beam acquisition performance of the collector by decreasing the final stage collector voltage attended with the reduction in the high frequency input level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling wave tube amplifier including a traveling wave tube and a power supply for operating the same.

[0002]

2. Description of the Related Art Traveling wave tube amplifiers are widely used as final stage amplifiers for repeaters or transmitters for broadcasting. There are various types of traveling wave tube amplifiers with an output of about 10 W to several kW, but most of the power consumption is the traveling wave tube amplifier because other devices are almost solidified in the repeater or transmitter. Are occupied. For this reason,
Reducing the power consumption of traveling-wave tube amplifiers, that is, improving efficiency, is an essential condition.

As one of the methods for reducing the power consumption of a traveling wave tube amplifier, the power consumed as a heat loss in a collector that captures an electron beam, which is a so-called spent beam, which has finished interacting with a high frequency in a slow wave circuit, can be minimized. There is a way to reduce it. That is, the collector voltage is lowered to a potential at which the slowest electron in the spent beam is captured to operate, that is, the collector potential is lowered, or the collector electrode is divided into a plurality of electrodes and different voltages are applied to each. There is a multi-stage collector potential reduction that distinguishes and captures the electrons of the spent beam according to each velocity.

As a traveling wave tube amplifier for which the power consumption is reduced in this way, there is conventionally known a stacking type amplifier in which respective power supplies are stacked with the cathode side being the lowest, as shown in FIG. This traveling wave tube amplifier has a two-stage collector 1
It is composed of a traveling wave tube 1 having 3 and a power supply 2 thereof. The traveling wave tube 1 includes an electron gun 3, a slow wave circuit 4, and a collector 13.
The electron gun 3 includes a cathode 7, a heater 8, a Wehnelt 9, and an anode 10. The electron beam emitted from the cathode 7 is focused by the beam focusing device 6 and passes through the slow wave circuit 4. At this time, the electron beam interacts with the high frequency input from the input coupling section 11 to amplify the high frequency. The amplified high frequency is extracted to the outside from the output coupling portion 12, the electron beam after the interaction, so-called spent beam, enters the collector, the slow one to the first collector 13a, and the fast one to the second collector 13b. Enter and be captured. The power supply 2 has power supplies 15, 16, 17, 18 for the second collector 13b, the first collector 13a, the slow wave circuit 4, and the anode 10 in order of increasing voltage with reference to the cathode terminal 19.
The terminals 20, 21, 22, and 23 as the power source terminals for the second collector 13b, the first collector 13a, the slow wave circuit 4, and the anode 10, respectively, and the heater power source 14 and its terminals as 19, 27. It is composed. The slow wave circuit 4 is at ground potential. There is also an individual method of configuring each power source other than the heater 8 with the cathode 7 side being common, but each power source is individually focused, but emphasis is placed on economical efficiency such as reduction in size and weight, low power consumption, and low cost. In some cases, a stacking method is generally used.

[0005]

In such a conventional traveling wave tube amplifier, the collector voltage is set in accordance with the velocity distribution at the saturated output where the velocity dispersion of the spent beam is the largest and the ratio of the slow electrons is large. Be done. Therefore, the amount of heat loss generated in the collector may be larger in the case of a small signal and in the non-excited state than in the saturated output. The effect is more remarkable as the number of collector stages is small and the beam conversion efficiency in the slow wave circuit is high.

Since the traveling-wave tube amplifier can be in all operating states from the saturated output to the non-excited state, it is necessary to design the heat in consideration of the state in which the amount of heat loss is the largest. For this reason, the collector of the traveling wave tube has a drawback that it cannot be miniaturized or the temperature of the member used, especially the temperature of the final stage collector, rises too much, in consideration of the case of small signal with the largest amount of heat loss and no excitation. there were.

[0007]

A traveling-wave tube amplifier according to the present invention detects a high-frequency input level of a traveling-wave tube and a control power source which is connected to a terminal for a final-stage collector of a power source to form a final-stage collector power source. And a detection circuit for feeding back this detection signal to the output voltage control unit of the control power supply as a signal for controlling the final stage collector voltage.

[0008]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a traveling wave tube amplifier according to the present invention, in which the collector has two stages. Power supply 2
A is a control power supply 2 connected to a collector terminal 20 of the final stage (second collector in this case) in the power supply 2 of the conventional example of FIG.
4 is connected, the terminal 25 is used as a power supply terminal for the final stage collector (the second collector 13b in this case), and the input level detection circuit 3 connected to the terminal 29 of the input circuit 28 of the traveling wave tube 1 is connected.
0, and the detection signal output terminal of the input level detection circuit 30 is connected to the output voltage control input terminal 32 of the control power supply 24.

The spent beam of the traveling wave tube has many slowest electrons at the time of saturated output and has a large velocity dispersion. Further, in the non-excited state, since there are no slow electrons and no velocity dispersion, all electron beams are incident on the final stage collector. Therefore, in the case of small signal and non-excitation, even when the collector voltage of the final stage is lower than that in the case of saturated output,
The electron beam trapping performance of the collector is not lost.

From the above, the power supply 2A shown in FIG.
By feeding back the high frequency input level detection signal to the output voltage control unit of the control power supply 24, the final stage collector voltage can be controlled according to the high frequency input level. The energy of the electron beam incident on the final stage collector is the smallest at the saturation output, and the energy increases as the high frequency input level decreases, so by decreasing the final stage collector voltage as the high frequency input level decreases, The heat load on the collector can be reduced without impairing the electron beam trapping performance of the collector.

[0011]

As described above, according to the present invention, the high frequency input level is used as a signal source for detecting the operating state of the traveling wave tube by providing the control power source and the high frequency input level detection circuit of the traveling wave tube. By lowering the final stage collector voltage as the high frequency input level decreases, the heat load on the collector can be reduced without impairing the electron beam trapping performance of the collector. This makes it possible to reduce the size and weight of the traveling-wave tube, which has conventionally been limited in design by the collector temperature at the time of small signal and no excitation.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a traveling wave tube amplifier of the present invention.

FIG. 2 is a block diagram of a conventional traveling wave tube amplifier.

[Explanation of symbols]

 1 Traveling Wave Tube 2, 2A Power Supply 13a First Collector 13b Second Collector 14 Heater Power Supply 15 Second Collector Power Supply 16 First Collector Power Supply 17 Slow Wave Circuit Power Supply 18 Anode Power Supply 24 Control Power Supply 28 Input Circuit 30 Input Level detection circuit

Claims (1)

[Claims] 1. A traveling-wave tube amplifier having a traveling-wave tube and a voltage-stacking type power supply for operating the traveling-wave tube, the control being connected to a terminal of a final-stage collector of the power supply to form a final-stage collector power supply. A traveling-wave tube amplifier, comprising: a power supply; and a detection circuit that detects the high-frequency input level of the traveling-wave tube and feeds this detection signal back to the control power supply as a signal for controlling the final-stage collector voltage.