JPH04256882A - Sending pulse generation circuit in pulse radar - Google Patents

Abstract

PURPOSE:To generate pulselike wave having an arbitrary envelope of mild ascent or decent at a pulse radar. CONSTITUTION:A timing control circuit 2 to generate a multitude of control triggar signals b1 to b5 with different timings by receiving a basic triggar signal (a), control pulse generation circuits 31 to 35 to generate control pulses c1 to c5 constituted of rectangular wave signal by receiving each control triggar signal, and driving circuits 41 to 45 to drive a load 5 by each control pulse constitute a transmission pulse generation circuit 100. By this, depending on the relation between the generation timing of the control triggar signal b1 to b5 and the duration time of the control pulse cl to c5, a current signal with mild ascent or decent is supplied to a magnetron 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission pulse generation circuit for generating pulsed radio waves in a pulse radar.

0002

[Prior Art] In a pulse radar that emits pulsed radio waves and measures the distance to a target by the time it takes for the radio waves to return, the transmitting section is generally connected to a high-voltage power supply circuit, a transmitting pulse generating circuit, and a magnetron. It is configured. The transmission pulse generation circuit receives a trigger signal and drives a pulse transformer with a constant pulse width, and has conventionally used a pulse shaping circuit using an LC circuit, a hard tube, an FET, or the like.

0003

SUMMARY OF THE INVENTION Such a conventional transmission pulse generation circuit is originally suitable for generating a transmission pulse having a constant pulse width with steep rises and falls. If target detection is performed by transmitting and receiving pulsed radio waves with a constant pulse width, the received pulse width will be constant regardless of the received signal strength.

However, when selecting only the necessary signals according to the strength of the received signal, for example, it is necessary to convert the received signal into multi-bit digital data and determine the received signal level based on the value. Analog signal processing has not been able to facilitate the identification of unnecessary signals. Furthermore, with conventional transmission pulse generation circuits, it has not been possible to create transmission pulses with arbitrary waveforms that have slow rises and falls.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission pulse generation circuit for a pulse radar, which is capable of generating a transmission pulse having an arbitrary waveform with a relatively slow rise or fall.

[0006]

[Means for Solving the Problems] A transmission pulse generation circuit in a pulse radar of the present invention includes a timing control circuit that receives a basic trigger signal and generates a plurality of control trigger signals with different timings, and a timing control circuit that receives each control trigger signal. A plurality of control pulse generation circuits each generate a rectangular wave signal that lasts until at least after the generation timing of the last control trigger signal that appears, and a plurality of control pulse generation circuits that drive a single load with the output signal of each control pulse generation circuit. It is characterized by comprising a drive circuit.

[0007]

[Operation] In the transmission pulse generation circuit in the pulse radar of the present invention, the timing control circuit receives a basic trigger signal and generates a plurality of control trigger signals with different timings, and the control pulse generation circuit receives each control trigger signal and generates a plurality of control trigger signals with different timings. Each generates a square wave signal. Further, each drive circuit drives a single load, such as a pulse transformer, by the output signal of each control pulse generation circuit. Since the rectangular wave signal output from the control pulse generation circuit described above lasts until after the generation timing of the control trigger signal that appears last, if the rectangular wave signal is generated simultaneously from the control pulse generation circuit, the corresponding The drive circuit that does this will simultaneously drive the load. The load supply power changes depending on the number of drive circuits that simultaneously drive this load.

Therefore, the waveform of the load supply power, that is, the transmission pulse, is determined by the relationship between the timing deviation of the plurality of control trigger signals generated by the timing control circuit and the duration of each rectangular wave signal generated by the plurality of control pulse generation circuits. The waveform is determined.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of the configuration of a transmitting section of a pulse radar according to an embodiment of the present invention. In FIG. 1, 100 is a transmission pulse generation circuit. The transmitting section includes a reference trigger signal generating circuit 1, a transmitting pulse generating circuit 100, a load 5 such as a pulse transformer, and a transmitting circuit 6 such as a magnetron. The reference trigger signal generation circuit 1 provides a reference trigger signal to the transmission pulse generation circuit 100. The transmission pulse generation circuit 100 drives the load 5 with a predetermined pulse waveform signal in synchronization with the reference trigger signal. As a result, the transmitting circuit 6 receives current supply through the load 5 and transmits a pulsed radio wave having a predetermined waveform.

The configuration and operation of transmission pulse generation circuit 100 in FIG. 1 are as follows.

The timing control circuit 2 receives the reference trigger signal a from the reference trigger signal generation circuit 1 and generates a plurality of control trigger signals b1, b2, . . . , each having a different timing.
Generates 5. If this timing control circuit 2 is an analog circuit, it includes a one-shot circuit that is triggered by the reference trigger signal a and continues for a predetermined time, and a circuit that generates a control trigger signal at the falling edge of each one-shot circuit. It can be configured by Further, if it is a digital circuit, it can be configured by a clock signal generation circuit and a counter that counts clock signals and generates a control trigger signal after a certain period of time has elapsed. The control pulse generation circuits 31, 32, . . . , 35 receive control trigger signals and generate rectangular wave signals having a predetermined period of time as control pulses c1, c2, . . ., c5, respectively. These control pulse generation circuits can be configured by a one-shot circuit if they are analog circuits, or can be configured by a counter that counts clock signals for a certain period of time if they are digital circuits. Drive circuit 41, 4
2...45 are the generated control pulses c1, c2.
...The load 5 is driven by c5. When the load 5 is a pulse transformer, for example, the drive circuits 41, 42...
Reference numeral 45 drives each primary side of the pulse transformer with a constant current. Therefore, the pulse transformer is driven in a superimposed manner by the drive circuits 41 to 45 that operate simultaneously.

Next, FIG. 2 shows waveforms of each part shown in FIG. 1. As shown in the figure, a plurality of control trigger signals b1 to b are generated at different timings after the reference trigger signal a is generated.
5 is generated. In this example, the control trigger signal b1 is generated at the same timing as the reference trigger signal a. The control pulse generation circuit 31 shown in FIG. 1 generates, as a control pulse, a rectangular wave signal c1 that lasts for a certain period of time T1 from the rise of the control trigger signal b1. The control pulse generation circuit 32 generates a control pulse c that lasts for a certain period of time T2 from the control trigger signal b2.
Similarly, the control pulse generation circuit 35 generates a control pulse c that lasts for a certain period of time T5 from the control trigger signal b5.
Generates 5. As shown in the figure, control pulses c1 to c5
The falling timings of all of the control trigger signals b1 to b5 continue until after the control trigger signal b5 that appears last, and in this example, the control trigger signals b1 to b5 are arranged so that each control pulse is symmetrical on the time axis with the control pulse c5 as the center. The generation timing of the control pulses c1 to c5 and the duration of the control pulses c1 to c5 are determined. Due to this signal, the load drive current increases sequentially from time t1 to t5, and decreases sequentially from t5 to t9. As a result, the supply current of the transmitting circuit (magnetron) is e
A pulsed radio wave is transmitted which changes in a substantially triangular wave as shown in FIG. 3, and whose envelope changes as shown in FIG.

Next, FIGS. 4 and 5 show an example of the configuration and waveform diagrams of the receiving section of the pulse radar.

In FIG. 4, a mixer circuit 10 mixes a signal from a local oscillation circuit 11 and an antenna reception signal to create an intermediate frequency signal, and an intermediate frequency amplifier circuit 12 mixes a signal from a local oscillation circuit 11 and an antenna reception signal to create an intermediate frequency signal, and an intermediate frequency amplifier circuit 12 mixes a signal from a local oscillation circuit 11 and an antenna reception signal to create an intermediate frequency signal.
The detection circuit 14 detects this and outputs a video signal. In the figure, 15 is a comparator, which binarizes the output signal v of the detection circuit 14 with reference to the reference voltage Vr.

FIG. 5 shows waveforms of input and output signals of the comparator 15 shown in FIG. Echo S1 with high received signal strength
is obtained as a wide signal, whereas the echo S2 with low received signal strength becomes a short signal.

Next, the operation of the transmission pulse generation circuit according to the second embodiment will be described. FIG. 6 shows waveforms of various parts of the circuit. Note that the circuit configuration is similar to that shown in FIG. 1st
The difference from the embodiment is that the control pulse generation circuits 31 and 32
...35 movements. As shown in FIG. 6, the control pulse generation circuit 31 generates a control pulse c1 that lasts for a certain period of time T from the rise of the control trigger signal b1, and the control pulse generation circuit 32 generates a control pulse c1 that lasts for a certain period of time T from the rise of the control trigger signal b2.
A sustained control pulse c2 is generated. Similarly, the control pulse generation circuit 35 generates a control pulse c5 that lasts for a certain period of time T from the rise of the control trigger signal b5. In this way, the duration T of each of the control pulses c1 to c5 is all constant, and the first generated control pulse c1 continues until after the rise of the last generated control trigger signal b5. With this configuration, the load (
The drive current of the pulse transformer (pulse transformer) increases sequentially, and decreases sequentially between time t5 and t9. Therefore, the first
Similarly to the embodiment, pulsed radio waves as shown in FIG. 3 are transmitted.

According to the second embodiment, since the power loss of the drive circuit that drives the load by each control pulse c1 to c5 is equal, it is possible to effectively utilize the rated capacity of each element constituting the drive circuit. can.

Note that in the first and second embodiments, the drive circuit 4
Although the circuits 1 to 45 supply equal constant currents to the load 5, each drive circuit may be weighted and the load may be driven in accordance with the weight.

[0019]

According to the present invention, by determining the generation timing of the control trigger signal and the duration of the control pulse, it is possible to generate a transmission pulse having an arbitrary waveform with a relatively gradual rise or fall. Therefore, for example, by slicing the received signal at a constant level, it becomes easy to obtain received signals with different widths depending on the received signal strength and extract only the desired echo.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transmitter of a pulse radar according to an embodiment.

FIG. 2 is a waveform diagram of each part of the transmission pulse generation circuit according to the first embodiment.

FIG. 3 is a diagram showing an example of transmitted radio waves obtained by the example.

FIG. 4 is a block diagram showing the configuration of main parts of a receiving section.

FIG. 5 is a waveform diagram of each part in FIG. 4;

FIG. 6 is a waveform diagram of each part of the transmission pulse generation circuit according to the second embodiment.

[Explanation of symbols]

15 Comparator 100 Transmission pulse generation circuit

Claims (1)

[Claims] 1. A timing control circuit that receives a basic trigger signal and generates a plurality of control trigger signals with different timings, and a timing control circuit that receives each control trigger signal and continues at least until after the generation timing of the last control trigger signal. A transmission pulse generation circuit in a pulse radar, comprising a plurality of control pulse generation circuits that each generate a rectangular wave signal, and a plurality of drive circuits that drive a single load using the output signal of each control pulse generation circuit.