JP3272484B2 - Radar pulse modulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar pulse modulator used in a pulse radar.

[0002]

2. Description of the Related Art FIG. 5 shows a configuration of a radar pulse modulator according to a conventional example. The circuit shown in FIG. 1 includes a magnetron 1, a pulse transformer 2, a pulse forming circuit 3, a thyristor 4, a thyristor gate resistor 5, a charge holding diode 6, a charge coil 7, and a constant voltage power supply 8.

The pulse forming circuit 3 is a circuit for forming a transmission pulse by discharging. The pulse forming circuit 3 is connected to a charging circuit composed of a constant voltage power supply 8, a charging coil 7 and a charge holding diode 6, and is charged by this charging circuit. The pulse forming circuit 3 is connected to a discharge switch including a thyristor 4 and a thyristor gate resistor 5. This discharge switch short-circuits the pulse forming circuit 3 to the pulse transformer 2 in response to a transmission trigger. As a result, the pulse forming circuit 3 discharges, and a transmission pulse is supplied to the magnetron 1 via the pulse transformer 2. The magnetron 1 supplies a microwave pulse-modulated by the transmission pulse to an antenna circuit (not shown).

[0004]

As described above, conventionally, a magnetron is used as a transmission tube.
An element such as a thyristor is used as a discharge switch. That is, a thyristor is used to satisfy a high withstand voltage and a large current. However, a switching element such as a thyristor used in such a discharge switch cannot be turned off immediately even if a trigger pulse is removed after a pulse is applied to the gate and turned on.
That is, a certain time is required to turn off. However, if the trigger due to noise is added in this turn-off time, that is, if false triggering is applied to the gate, the thyristor can not be turned off, continuous discharge occurs in the pulse forming circuit as shown in FIG. 6 Would. When the pulse forming circuit discharges continuously,
A transmission tube such as a magnetron cannot be driven properly.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to prevent a pulse forming circuit from continuously discharging even when a false trigger related to noise or the like occurs. Aim.

[0006]

In order to achieve the above object, a radar pulse modulator according to the present invention comprises a pulse forming circuit for receiving a charge from a charging circuit and forming a transmission pulse at the time of discharging, and a pulse forming circuit. A transmission tube for generating a transmission signal modulated by a transmission pulse in accordance with the discharge of the pulse, a discharge switch for discharging the pulse forming circuit, and a transmission so that the pulse forming circuit discharges at a predetermined timing and forms a transmission pulse of a predetermined width. A control circuit that controls the discharge switch in response to a trigger, and a false trigger operation that interrupts control of the discharge switch by the control circuit after the pulse forming circuit discharges, at least until the discharge switch does not malfunction due to a false trigger to the control circuit. And a blocking circuit.

Further, the pulse modulator for radar according to the present invention comprises:
The control circuit includes: means for generating a drive trigger having a width corresponding to the transmission pulse width in synchronization with the transmission trigger; and a first active element driven by the generated drive trigger. Means for generating a stop pulse having a width corresponding to the transmission repetition frequency in synchronization with the drive trigger, and a second active element driven by the generated stop pulse, wherein the first and second active elements are The pulse forming circuit is connected to a discharge switch so that the pulse forming circuit discharges only when the driving trigger and the blocking pulse are simultaneously generated.

[0008]

In the radar pulse modulator of the present invention, after the discharge of the pulse forming circuit, the control of the discharge switch by the control circuit is interrupted at least until the discharge switch does not operate due to a false trigger. That is, when an erroneous trigger is added to the transmission trigger, the control of the discharge switch by the control circuit according to the erroneous trigger is not performed. Therefore, even when an element such as a thyristor is used as a discharge switch, continuous discharge of the pulse forming circuit is prevented, and a transmission tube such as a magnetron is driven correctly.

Further, in the radar pulse modulator of the present invention, the blocking pulse for driving the second active element is the first pulse.
Are generated in synchronization with a drive trigger that drives the active element of the second. The pulse forming circuit discharges only when the drive trigger and the inhibition pulse are simultaneously generated. Since the pulse width of the transmission pulse is set according to the transmission repetition frequency,
In the present invention, the duration of the false trigger operation prevention operation is controlled in accordance with a plurality of types of transmission repetition frequencies for obtaining transmission pulses having different pulse widths. Obtained stably.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. The same components as those of the conventional example shown in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows a configuration of a radar pulse modulator according to a first embodiment of the present invention. The pulse modulator for radar shown in this figure is different from the circuit shown in FIG. 5 in that a thyristor gate trigger transformer 9, a trigger driving transistor 10, a blocking pulse driving transistor 11, PR
The configuration is such that an F determination unit 12, a drive trigger generation unit 13, and a stop pulse generation unit 14 are added.

The thyristor gate trigger transformer 9 is a transformer connected to the thyristor gate resistor 5, and is used to trigger the gate of the thyristor 4. The input side of the thyristor gate trigger transformer 9 has a trigger driving transistor 10 and a blocking pulse driving transistor 1
1 are connected in series. Trigger drive transistor 1
Numeral 0 denotes a transistor driven by the drive trigger generated by the drive trigger generator 13, and the inhibition pulse drive transistor 11 is a transistor driven by an inhibition pulse generated by the inhibition pulse generator 14. Only when both transistors 10 and 11 are on, the gate of thyristor 4 will be triggered.

The PRF determination unit 12 determines a PRF (transmission repetition frequency) according to a range signal supplied from a radar display (not shown), that is, a signal indicating a display range of the radar display. The drive trigger generator 13 generates a drive trigger according to a transmission trigger supplied from the radar display, that is, a trigger indicating a transmission timing. The pulse width of the drive trigger generated by the drive trigger generation unit 13 is equal to the PRF determined by the PRF determination unit 12.
Is set to a pulse width corresponding to a required transmission pulse width. The blocking pulse generator 14 is provided with the PRF determiner 12
A blocking pulse having a pulse width corresponding to the PRF determined by the above is generated in synchronization with the driving trigger generated by the driving trigger generating unit 13.

FIG. 2 shows the operation of this embodiment. As shown in this figure, the drive trigger is generated in synchronization with the front edge of the transmission trigger. The blocking pulse turns off in synchronization with the drive trigger, and keeps the off state for a time required for turning off the thyristor 4. Therefore, even when the false trigger is superimposed on the transmission trigger, the pulse forming circuit 3 does not continuously discharge.

The short pulse shown in FIG. 2A (when the PRF is relatively high) and the long pulse shown in FIG. 2B (the PRF is relatively low) The time during which the blocking pulse continues the off state is set to a different value. This is because the PRF determination unit 12 determines the PRF, and the inhibition pulse generation unit 14 generates an inhibition pulse based on the determination result. By such an operation, in the present embodiment, PR
A plurality of different types of transmission pulses can be stably obtained corresponding to the difference in F.

FIG. 3 shows the configuration of a radar pulse modulator according to a second embodiment of the present invention. The circuit shown in this figure also has a trigger drive transistor 10, a blocking pulse drive transistor 11,
A PRF determination unit 12, a drive trigger generation unit 13, and a stop pulse generation unit 14 are provided. This embodiment is different from the first embodiment in that the trigger driving transistor 10 and the blocking pulse driving transistor 11 are not connected to the thyristor gate resistor 5 via the thyristor gate trigger transformer 9 but the trigger driving transistor 10 And the connection point of the blocking pulse drive transistor 11 is connected to one end of the thyristor gate resistor 5.

With such a circuit configuration, the logic of the blocking pulse is opposite to that of the first embodiment. That is, the logic is as shown in FIG. With such a circuit configuration, the same effects as in the first embodiment can be obtained.

In the drawing, V ₁ is a constant voltage for triggering the gate of the thyristor 4.

[0019]

As described above, according to the present invention,
Since the control of the discharge switch by the control circuit is interrupted at least until the discharge switch does not malfunction due to an erroneous trigger after the pulse forming circuit discharges, even when an element such as a thyristor is used as the discharge switch, the pulse formation is performed. Continuous discharge of the circuit can be prevented. Therefore, a state in which the transmission tube cannot be driven due to the occurrence of a false trigger is prevented, and a more reliable radar pulse modulator can be obtained.

In the radar pulse modulator according to the present invention, the first and second active elements are provided so that the pulse forming circuit discharges when the driving trigger and the blocking pulse are simultaneously generated. Because the pulse width of the pulse is set according to the transmission repetition frequency and this blocking pulse is generated in synchronization with the drive trigger,
The above-described effect can be realized while adapting to the difference in the transmission repetition frequency. Therefore, it is possible to stably realize the operation of the transmission tube with a plurality of different pulse widths.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a circuit configuration of a radar pulse modulator according to a first embodiment of the present invention.

FIG. 2 is a waveform chart showing the operation of this embodiment.
FIG. 2A shows a case of a short pulse, and FIG. 2B shows a case of a long pulse.

FIG. 3 is a circuit diagram showing a circuit configuration of a radar pulse modulator according to a second embodiment of the present invention.

FIG. 4 is a waveform chart showing the operation of this embodiment.
4A is a diagram showing a case of a short pulse, and FIG. 4B is a diagram showing a case of a long pulse.

FIG. 5 is a circuit diagram showing a circuit configuration of a radar pulse modulator according to a conventional example.

FIG. 6 is a waveform diagram showing a problem of the conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 magnetron 2 pulse transformer 3 pulse forming circuit 4 thyristor 5 thyristor gate resistor 6 charge holding diode 7 charging coil 8 constant voltage power supply 9 thyristor gate trigger transformer 10 trigger drive transistor 11 blocking pulse drive transistor 12 PRF determination unit 13 drive trigger generation unit 14 Blocking pulse generator V ₁ Constant voltage for thyristor gate drive trigger

Claims (1)

(57) [Claims] 1. A pulse forming circuit for receiving a charge from a charging circuit and forming a transmission pulse at the time of discharging, a transmitting tube for generating a transmission signal modulated by the transmitting pulse in accordance with the discharging of the pulse forming circuit, and discharging the pulse forming circuit. A discharge switch for controlling the discharge switch in response to a transmission trigger so that the pulse forming circuit discharges at a predetermined timing and forms a transmission pulse having a predetermined width; and at least the discharge switch controls after the pulse forming circuit discharges. An erroneous trigger operation prevention circuit that interrupts the control of the discharge switch by the control circuit until the circuit does not malfunction due to an erroneous trigger to the circuit, and the control circuit transmits a drive trigger having a width corresponding to the transmission pulse width. Means for generating a signal in synchronization with the trigger, and a first active element driven by the generated drive trigger; A trigger operation blocking circuit including: means for generating a blocking pulse having a width corresponding to the transmission repetition frequency in synchronization with the driving trigger; and a second active element driven by the generated blocking pulse; A pulse modulator for radar, wherein the two active elements are connected to a discharge switch so that the pulse forming circuit discharges only when a drive trigger and a blocking pulse are simultaneously generated.