JPS59225610A - Pulse modulator - Google Patents

Abstract

PURPOSE:To attain stably parallel operation by inserting a diode isolating electrically each switching element connected in parallel and a PFN with respect to a line type modulator used for a radar equipment. CONSTITUTION:The diode 8 for isolation is added to a conventional parallel operating system in order to avoid interference between units having each a switching element 4, a PFN5 and a pulse transformer 6 as a pair. The PFN is charged to about twice an output voltage of a DC power supply 1 by means of the series resonance between a charging choke 2 and the capacitive component of the PFN5 of each unit. when a TX trigger is applied externally to the switching element 4, the energy charged in the PFN is discharged through the corresponding switching element 4 and pulse transformer 6. Even if there is a variation in the ON-time of each switching element or a difference of the impedance, since the discharge current of the PFN is blocked by the diode 8 for isolation, the current does not flow through the other unit.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a line type modulator for use in radar equipment.

A line type modulator used in conventional radar equipment has a basic configuration as shown in FIG.
It is charged to approximately twice the output voltage of the DC power supply 1 by series resonance operation with the capacitance of the DC power supply 1. The energy charged in the PFN 5 is discharged by the switching element 4 via the pulse transformer 6 in synchronization with an external TX trigger, and the required modulation pulse amplified by the large power amplifier 7 is supplied to the transmission tube which is the load. In the figure, 3 is a hold-off diode.

Here, if the power capacity of the transmitting tube increases.

Although it is conceivable that the discharge current of the switching element 4 is extremely large and exceeds the entire allowable current, the current capacity is generally increased by connecting switching elements or switching parts including the PFN'ij7 in parallel as shown in Figs. 2 and 3. method has been used.

In Figure 2, the required number of switching elements 4f are connected in parallel, but in order to distribute the discharge current evenly when discharging the charging energy of the PFNj, the switching speed, impedance, etc. of the switching element 4 must be adjusted. Although it is necessary to match the characteristics, it is actually very difficult to do so, and there is a defect that causes an imbalance in the current of each switching element.

Figure 3 shows that in order to compensate for the defect in Figure 2, the required number of pairs of PFN 5 and switching element 4 are connected in parallel, and the energy charged in one PFN is discharged by one corresponding switching element. This is to equalize the current of each switching element, and finally the pulse transformer is used to equalize the current of each switching element.
This method obtains a large current by adding. In general radar equipment, a means of increasing output power by parallel operation such as the unlucky method has been used. P of
There was a drawback that the FN charging current flowed, exceeding the allowable radio wave limit and easily damaging the switching elements.

When performing parallel operation as described above in a line type modulator of a radar device, it is difficult to make the switching characteristics, impedance characteristics, etc. of the switching elements 4 the same, so there is a problem that the discharge currents of the switching elements 4 are not uniform.

The non-invention is to solve the above-mentioned problem by inserting a diode 8t for electrically isolating each switch, switching element 4, and PFNiJ2 connected in parallel as in the fourth factor, and to provide a method for stable parallel operation. be. It is also possible to provide this diode 8 with a hold-off diode 30 function.

That is, one aspect of the present invention is that in a transmitting device in which a plurality of modulator units each having a PFN and a switching element, which are basic constituent elements of a line type modulation system, are connected in parallel and their powers are summed, the discharge current of the PFN exceeds the switching accumulation of other units. The pulse modulator is characterized in that a pulse modulator is provided corresponding to each individual unit to prevent the pulse from flowing through the pulse modulator.

An embodiment of the present invention will be described using FIG. 4. Fourth
The figure shows that compared to the general parallel operation system as shown in Figure 3, switching elements 4. PFN5 and pulse transformer 6t-
In order to eliminate interference between each unit in a set, an isolation diode 8 is added. As shown in Figure 4, the PFN is
t - What is the output voltage of DC power supply 1? 'tl! Charge twice. Then, when an external JTX signal is applied to the switching element 4, the energy charged in the PPN is discharged via the corresponding switching element 4 and pulse transformer 6. Here, even if there are variations in the on-time of each switching element or differences in impedance, etc., the discharge current of the PFN is re-locked by the isolation diode 8, so it flows through the other units =, )1-. Therefore, each switching element has a corresponding P
Since current flows only for the energy charged in the FN, stable parallel operation can be performed without causing accidents such as damage due to overcurrent.

The present invention is a system for increasing power capacity through parallel operation of a line-type modulator of a radar device, by providing an isolation diode 8 as shown in FIG.
It has the effect of stable parallel operation without the need for troublesome equalization adjustments such as fluctuations and impedance characteristics.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional line type modulator. 2 and 3 are circuit diagrams showing a conventional example of parallel operation of switching elements, and FIG. 4 is a circuit diagram showing an embodiment of the invention. l...High voltage DC power supply, 2...Charging choke, 3...Hold-off diode, 4...Switching element, 5... P
FN, 6...) (Rustrans, 7...)
・High power amplifier tube, 8...Isolation diode.

Claims (1)

[Claims] In a pulse modulator in which a plurality of 7 modulator units each having a pulse shaping circuit and a switching element, which are basic constituent elements of a line type modulation method, are connected in parallel and the resulting plurality of parallel outputs are summed, the pulse shaping circuit 1. A pulse modulator characterized in that each unit is provided with means for preventing discharge current from flowing into a switching element of another unit.