US 3774112 A
A control circuit for a radar or sonar or other radiating system having a megatrol-high energy switch. The control terminal of the switch is coupled to the signal pulse source for the radiating system and the main electrodes of the switch are coupled in series with the radiating system output and the radiating element.
Description (OCR text may contain errors)
States Patent Panico Nov. 20, 1973 I5 MEGATROL-HIGH ENERGY 2,534,261 12/1950 Gorman et al 325/164 TRANSMITTER sw 2,750,503 6/1956 Gottier 325/164 2,658,993 11/1953 Sceley 325/164 [7 5 Inventor: Joseph J. Panico, Arlington, Mass.
, OTHER PUBLICATIONS  Asslgnee: Health Systems, lnc.,Woburn.
Mass M. I. Sko1n1k, lntroductlon to Radar Systems",
McGraw-Hill, 1962, pp. 248-255.  Filed: Dec. 16, 1971  Appl. No.: 208,764 Primary Examiner-Benjamin A. Borchelt Assistant ExaminerG. E. Montone Related Apphcamm Data Attorney-Edward F. Costigan  Division of Ser. No. 30,385, April 21, 1970, Pat. No.
 ABSTRACT  US. Cl 325/164, 328/91, 343/l7.1 R A control circuit for a radar or sonar or other radiat-  Int. Cl H04b 1/04, (1015 7/28 ing system having a megatrol-high energy switch. The  Field of Search 315/845; 328/91; control terminal of the switch is coupled to the signal 325/27, 164, 121; 343/5 R, 17.1 pulse source for the radiating system and the main electrodes of the switch are coupled in series with the  References Cited radiating system output and the radiating element.
UNITED STATES PATENTS 1 Claim, 7 Drawing Figures 2,478,907 8/1949 Edgerton 315/845 3,114,077 12/1963 Spindle 3,396,388 8/1968 Goldie 343/5 R TIPA/VSM/TTFE PAD/W I: 540/4 7//V6 some 1 q 52 EMl-A/T BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to basic high speed, high energy capacity switches and more particularly pertains to a gaseous element which is controlled and provides a light spectrum output as well as providing a power transfer function.
2. Description of the Prior Art In the field of electronic and electrical switching it has been the general practice to employ a variety of special devices such as relays, contact switches, manual and remote, thyratrons, solid state elements such as silicon controlled rectifiers. Such devices have been found unsatisfactory in that they are limited in their current and voltage capacities and speed of operation. This is particularly true in the case of both the SGR, where limiting values of current and voltage exist due to the physical characteristics and the nescessity of dissipating large heat accumulations, and for gas tubes such as the Thyratron where, although high currents can be accommodated, voltage and switching time limitations exist as well as the fact that the ignition and sustaining voltages are fixed parameters. These two devices, although extensively applied, are essentially unidirectional in conduction; thus they are not interchangeable for all applications with standard swtich elements and do not have both switch terminals isolated. Relays and contact switches are clearly slow acting devices and subject to periodic breakdown when operating at high voltage and current. Moreover, none of these elements in and of themselves provide any secondary output or indicia of their operation, a useful output, where, a multifunction switch is necessary without additional elements or equipment. Those concerned with the development of switches and elements have long recognized the need for a high capacity, fast acting, bidirectional, and multipurpose switch. The present invention satisfies this requirement.
SUMMARY OF THE INVENTION The general purpose of this invention is to provide a radiating system switch that has all the advantages of similarly employed prior art devices and has none of the above described disadvantages. To attain this, the present invention provides a unique arrangement of a Xenon or Krypton flash tube whose main electrodes are connected in series with the load or line to be switched while a control pulse is applied between the control terminals thereof. One control terminal being any surface proximate the glass envelope of the tube may be raised to the necessary ignition potential. In pulsed radar and sonar the switch is interposed between the transmitter/receiver and the radiating component with the switch control signal supplied as the pulse command from the T/R.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of a Xenon flash tube with a control electrode disposed thereon.
FIGS. 2 and 2a are block diagrams of embodiments made in accordance with the principle of this invention;
FIG. 3 is a schematic diagram of an embodiment of the instant invention;
FIGS. 4 and 5 illustrate novel trigger circuits for the switch;
FIG. 6 shows the switch employed in a sonar or radar system;
In the illustrated embodiment of FIG. 1 a gas discharge tube 10 filled with Xenon or Krypton gas enclosed in a glass envelope 11.(or other suitable enclosure) has therein a pair of main discharge electrodes 12 and 13. A control terminal or electrode 14 can assume a variety of shapes and positions since all that is necessary is to provide a short duration voltage across the gas to the main electrodes. This can be accomplished by afiixing an electrical conductor proximate to or on the envelope 11. Wrapping a wire therearound or an electrically conducting tape 14, or a thin layer of conducting paint applied directly to the envelope, will provide sufficient lotential to break down the gas and initiate the main discharge. The type of control element employed depends on the tube use so that where light emission is a factor, a wire or transparent tape is selected. It should be noted that as in most gaseous discharge tubes, a particular voltage between the main electrodes is required to sustain ignition or firing after the control terminal has activated or fired the tube. Recent developments in Xenon and Krypton flash tubes have included what can be generally termed as doping. Various of these techniques have lead to the fabrication of a series of tubes which can sustain ignition at different currents and potentials. These parameters can be selectively determined in the manufacture of the tubes and, tubes can be obtained having sustaining voltages from approximately 300 volts to tens of thousands of volts. Tubes of this type are manufactured and available from the Xenon Corporation, Medford, Massachusetts and are fully described in their brochures on linear Xenon flash tubes designated as Novatron series 100, 200, 400 and 600. By combining, with the Xenon discharge tube 10, a source of ignition voltage and sufficient main electrode voltage the tube can be made to fire or ignite and emit a high light intensity very close to that of natural sunlight. In the embodiment of FIG. 2, a trigger circuit 15 has its output 15 connected between the control terminal 14 and one main electrode 19' while the two main electrodes are connected across the series combination of a load 16 and an electrical power source 17. Many circuits are presently available to provide a relatively narrow pulse and any of these are suitable for the purpose of supplying ignition potential. For selective firing the triggercircuit must be activated and a control signal input 18 thereto has been shown. This control signal can be provided through the action of a manual or electronic switch. In operation, when the load 16 and power source 17 are connected across the Xenon tube and the trigger circuit 15 activated, the tube fires and conducts therethrough the load current. The trigger circuit which may include the control signal source and the Xenon discharge tube in combination comprise a switch module which will be referred to hereinafter as the Megatrol." In essence, the Megatrol is controlled in a manner similar to a relay or a silicon controlled rectifier. In order to close the main switch contacts a small amount of energy is applied to the control terminal permitting current to flow from the power supply through the load. As in the SCR, the main switch contacts reopen when the (voltage) current through the switch is insufficient to maintain conduction, but, unlike the SCR, current can flow in either direction (bidirectional). Once the Megatrol is extinguished it will not turn on again until the control terminal is activated. It is capable of controlling vast amounts of power through only minute control levels. For example, the Megatrol switch can easily hold off voltages in excess of 10,000 volts and conduct thousands of amperes while exhibiting an extremely high switching speed. FIG. 2a shows one possible multipole switch arrangement wherein another tube has been added to the module so that two or more loads can be simultaneously controlled.
An operative embodiment of the blocks of FIG. 2 is illustrated in FIG. 3 where a bias voltage is supplied to the anode 18 of an SCR 19 through a diode 20. Since the SCR 19 is off" the bias voltage will cause capacitor 21 to charge to the desired level. Simultaneously capacitor 22 will be charged to a level established to the voltage divider comprising resistors 23 and 24. When switch 25 is closed the neon gas tube 26 will breakdown permitting current to flow through resistor 27 to ground and apply a voltage at the gate 28 of SCR 19 causing the SCR to short capacitor 21 to ground through its cathode 29. This discharges the capacitor and abruptly changes the voltage at the primary winding 30 of step-up transformer 31 which is coupled to the secondary 32 and provides a sufficient voltage pulse at the control terminal 14 to ignite the Xenon tube 10. The secondary has one end 33 thereof connected to the control terminal 14 and the other end 34 connected through capacitor 35 to one of the main Xenon electrodes. It has been found that this capacitor 35 in the secondary circuit provides proper operation, reliability and improved results. More important, the capacitor electrically isolates the switch terminals from the control circuitry. Once conducting the load current, the Xenon tube will continue until it is extinguished by a decrease in (current) energy therethrough.
In certain applications and conditions the applied voltage V is insufficient to breakdown the tube and initiate ignition. Considering FIG. 4, a voltage pulse 36 is injected through capacitor 37 to the main electrode 12 thus applying a voltage V V,, which is sufficient to start ignition. Diode 38 blocks the positive pulse from the source of power while diode 39 absorbs the negative transient which passes through capacitor 37 when the tube switches on. FIG. indicates another novel trigger circuit wherein two discharge tubes are connected in series between the power source 17 and the load 40. A switch 41 is connected between the power source and a trigger input 42 to main electrode 43 of Xenon tube 44. With this switch 41 open no current will flow since the source voltage V is not great enough to breakdown both tubes 44 and 45 in series. However, when the switch is closed tube 44 will start conducting and will effectively lower its impedance so that the voltage across tube 45 will be sufficiently high to fire it and cause conduction in an avalanche mode. It should be noted that on conduction the voltage drop across tube 44 is practically zero due to the low conduction resistance.
FIG. 6 illustrates a Megatrol used with either a radar or sonar transmitter 71 such that the output of the transmitting section is applied to one electrode of the Megatrol and the other to the radiating element 72. That is the Megatrol is interposed between the transmitter and the radiator with the pulse command signal from the transmitter providing the input to the control terminal of the Megatrol along line 73. The Megatrol is excellent in this arrangement since it is capable of passing large level, high frequency energy, without loading the circuit.
It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims.
1. A controlled high frequency energy transmitter comprising:
a source of high-frequency energy;
a radiating element for said energy;
a high speed, high energy capacity switch connecting said source and said radiating element comprising;
a gas filled bidirectional discharge flash tube having a pair of main electrodes and a control terminal for initiating the firing of said tube;
a first diode;
said first diode being coupled in circuit with the energy source and the radiating element and the connection being coupled across said electrodes;
a high voltage pulse source;
means for actuating said pulse source coupled thereto;
means coupling said pulse source to said flash tube;
said coupling means comprising a capacitor having one side coupled to said pulse source and the other side coupled to one of said electrodes and to said terminal;
a second diode coupled to said pulse source;
a resistor coupling said diode to the other of said electrodes;
said first diode acting to block said pulse source from said energy source; and
said second diode acting to absorb transients from said capacitor when said flash tube switches on.