JPS6356722B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulse modulator for generating a radar transmission signal that generates a large output pulse for modulating a radar transmission tube, and particularly to a pulse modulator for generating a modulator pulse output voltage during stagger operation in an MTI radar. The present invention relates to a pulse modulator for generating a radar transmission signal with stabilization.

Conventionally, there is a pulse modulator as shown in FIG. That is, the power supply 1 has a hold-off power supply via the charging station (or charging station transformer) 2.
The anode side of the diode 3 is connected, and the cathode side of the hold-off diode 3 is connected to a pulse forming circuit (hereinafter referred to as PFN) that determines the pulse width of the modulator.
) is connected to one end of 4. The other end of the PFN 4 is connected to the power source 1 via a load 5 such as a magnetron or klystron via a pulse transformer. A switching element 6, such as a thyristor or thyratron, which forms a closed circuit with the PFN 4 and the load 5, is connected between the connection point between the power supply 1 and the load 5 and the cathode side of the hold-off diode 3. Switching element 6
A trigger circuit 7 that generates a trigger to close the switching element 6 is connected to the switch. The charging circuit 2 and the PFN 4 form a resonant charging circuit, and the hold-off diode 3 keeps the resonant charging voltage caused by the PFN 4 and the charging circuit 2 constant.

Figures 2 and 3 show the voltage waveforms at each part in Figure 1. Figure 2 shows the general case where the trigger signal period is constant, and Figure 3 shows the staggered operation where the trigger signal period changes. It shows the case. That is, if the period T of the output trigger of the trigger circuit 7 of FIG. 1 is constant as shown in FIG. After ₀ , the charging voltage of PFN4 is charged to the maximum voltage and held by the hold-off diode 3 for a time T- _T0 , and then the charging voltage of PFN4 is discharged by the operation of the switching element 6, and the charging voltage of PFN4 is discharged as shown in Fig. 2c. A pulse voltage -V is generated at the load 5 as shown in FIG.

Furthermore, as shown in FIG. 3a, in the case of staggered operation in which the periods T ₁ , T ₂ , T ₃ , T ₄ . . . of the output trigger of the trigger circuit 7 vary, the operation is similar to that described above,
_{As shown in FIG .}
T ₀ ), T ₃ ′ (=T ₃ −T ₀ ), T ₄ ′ (=T ₄ −T ₀ ), etc. are no longer constant. Then, Hold Off
Although the charging voltage of PFN 4 is held by the diode 3, it actually decreases slightly during the above-mentioned holding time. That is, in the closed circuit formed by the PFN 4, the load 5, and the switching element 6, the resistance value of the switching element 6 is not completely infinite even in the open state, and the hold-off diode 3
Due to leakage current, etc., the voltage charged in the PFN4 capacitor decreases over time.
If this decrease is ΔV, then when the trigger period T is constant as shown in Figure 2a, ΔV is also constant for each trigger, but as in the staggered operation of Figure 3a, the period T ₁ , When T ₂ , T ₃ , T ₄ ... are different, ΔV is the retention time T ₁ '(=T ₁ - _{T 0} ), as shown in FIG.
T ₂ ′(=T ₂ −T ₀ ), T ₃ ′(=T ₃ −T ₀ ), T ₄ ′(=T ₄ −
T ₀ ), ΔV ₁ , ΔV ₂ , ΔV ₃ , ΔV ₄ ...
As shown in FIG. 3c, the pulse voltages -V ₁ , -V ₂ , -V ₃ and -V ₄ generated in the load 5 also vary.

Therefore, in the case of pulse modulator loads used in radars, etc., such as magnetrons, traveling wave tubes, and cross-field magnetic amplifiers (CFA), frequency and output fluctuations occur for each pulse, which causes instability in the system. It was hot.

The present invention eliminates the above-mentioned drawbacks, and the repetition period of the trigger signal fluctuates as in staggered operation, resulting in PFN due to the hold-off diode.
Even if the holding time of the charging voltage differs for each pulse,
It is an object of the present invention to provide a pulse modulator for generating a radar transmission signal that can always obtain a constant modulator pulse output voltage.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, in which a charging station (or charging station transformer) 2 and a PFN4
A switching circuit 8 is provided between the hold-off diode 3 in FIG. 1 and a trigger generator 9 that generates a trigger to control the switching circuit 8. Ru. The switching circuit 8 is a circuit including a switching element such as a thyristor or a thyratron, and also has a conventional function of holding a charging voltage. In FIG. 4, the same parts as in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

In the pulse modulator configured in this manner, by controlling the timing of the trigger applied to the switching circuit 8 by the trigger generator 9, resonance charging is performed so that the holding time of the charging voltage of the PFN 4 is constant. Controls the time it starts. The principle is described below.

FIG. 5 shows waveforms at various parts in FIG. That is, as shown in FIG. 5a, the periods of the output trigger signals of the trigger circuit 7 are assumed to be T ₁ , T ₂ , T ₃ , T ₄ . Further, when the charging time of the pulse forming circuit 4 is T ₀ and the charging voltage holding time is T, the trigger is set such that the sum (T ₀ +T) of the charging time T ₀ and the charging voltage holding time T becomes a constant value. From the generation of the signal, T ₁ ′ = T ₁ − (T ₀ +
T), T ₂ ′=T ₂ −(T ₀ +T), T ₃ ′=T ₃ −(T ₀ +T),
The output signal of the trigger generator 9 is applied to the switching circuit 8 after a time delay of T ₄ '=T ₄ -(T ₀ +T).
That is, the output signal of the trigger generation circuit 9 is generated based on, for example, the generation timing of the output trigger signal of the trigger generation circuit 7, as shown in FIG. 5b.
T ₁ ′, T ₂ ′, T ₃ ′... are generated with a delay. By applying this trigger signal, the switching circuit 8 becomes conductive, and as shown in FIG. 5c, the charging station 2 and
Start resonant charging of PFN4. After time _T0 , the charging voltage becomes maximum and the switching circuit 8 holds this charging voltage. Furthermore, since the switching element 6 operates after a time T, the charging voltage of the PFN 4 is discharged through the load 5, and a pulse voltage -V' is generated in the load 5, as shown in FIG. 5d. in this case,
Similar to the conventional circuit, the capacitor of PFN4 discharges during the holding time T, and the charging voltage decreases by ΔV. However, unlike the conventional circuit, the holding time T is constant regardless of the stagger period, so each pulse ΔV is also constant at each time, resulting in stable output pulse voltage -
V′ is obtained.

As can be seen from the above explanation, the output pulse voltage of the pulse modulator during stagger operation can be stabilized by controlling the start time of resonance charging of the PFN 4 using the switching circuit 8 and the trigger generator 9. Can be done.

As described above, according to the present invention, by providing a switching circuit and a trigger generator for controlling the charging start time of the PFN, the output pulse voltage of the pulse modulator during stagger operation can be easily stabilized. effective.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an example of a conventional pulse modulator, and FIGS. 2 a to c are voltage waveform diagrams of various parts of the pulse modulator shown in FIG. 3a to 3c are voltage waveform diagrams of various parts in the case of stagger operation in which the trigger period of the pulse modulator shown in FIG. 1 changes, FIG. 4 is a configuration explanatory diagram showing one embodiment of the present invention, and FIG. 4A to 4D are diagrams showing examples of voltage waveforms at various parts of the pulse modulator shown in FIG. 4; 1...Power source, 2...Charging station (or charging station transformer), 4...Pulse forming circuit, 5...Load,
6... Switching element, 7... Trigger circuit, 8... Switching circuit, 9... Trigger generator.

Claims (1)

[Claims] 1 A pulse forming circuit connected to a power source, a load connected to this pulse forming circuit, and a charging voltage of the pulse forming circuit connected to the load and the pulse forming circuit to form a closed circuit in the closed state. and a means for controlling the charging start time of the pulse forming circuit so that the time from the start of charging of the pulse forming circuit to the closing state is constant. Pulse modulator for transmitting signal generation.