JPH0560281B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to an injection-locked modulation device that modulates and outputs a high-frequency signal such as a microwave, and in particular, the present invention relates to an injection-locked modulation device that modulates and outputs a high-frequency signal such as a microwave, and in particular, a separated slave modulator that maintains stable operation. The present invention relates to an injection-locked modulation device that can perform injection locking.

(b) Prior art and problems FIG. 1 is a block connection diagram of a conventional injection-locked modulator.

In the figure, a main modulator 1 and a sub modulator 2 convert high frequency signals such as microwaves into modulated signals.
This is a modulator that performs FM modulation and outputs, and main modulator 1
The output from the is applied to the slave modulator 2 via the switch 3, the circulator 5, and the switch 4, so the slave modulator 2 is synchronized with the main modulator 1, and the output terminal 6 receives the power of the slave modulator 2. (modulated microwave output)
is obtained.

In an injection-locked modulator operating in such a state, if the output of the slave modulator 2 is cut off or if the modulation characteristics deteriorate or the characteristics deteriorate such as a change in the oscillation frequency, this slave modulator 2 If the modulator 2 is disconnected and only the main modulator 1 is operated, and in the opposite case, the main modulator 1 must be disconnected, but in either case, the operation can be performed without momentary interruption.

On the other hand, while testing this modulation device, it may be necessary to test only the characteristics of the slave modulator 2. At this time, if injection locking remains, only the characteristics of the main modulator 1 can be seen, so in order to make the slave modulator 2 independent, switch 4 is used.
When the connection with the circulator 5 is cut off, the load on the slave modulator 2 is released, so that the output sent from the modulator 2 is totally reflected at the open end and returns to itself. For this reason, this slave modulator 2 may stop oscillating or become unstable.

To avoid this, in the case of an injection-locked modulator,
For example, by inserting a 3 dB attenuator (not shown) into the output line of the slave modulator 2, or by adjusting the length of the output line a as shown in the figure, the impedance is changed and oscillation is performed stably. I'm looking for points.

Inserting an attenuator to avoid the instability of oscillation as described above will reduce the output power, and the adjustment method for output line a must be adjusted in the same state as when it is installed in the device. There were some difficult problems.

(c) Purpose of the Invention The present invention has been made in view of the problems of the prior art described above, and is designed to operate stably even when the slave modulator, which is injection-locked by the main modulator, is disconnected and operated independently. The purpose of the present invention is to provide an injection-locked modulation device that has the following characteristics.

(d) Structure of the Invention The object of the above invention is to apply the outputs of the main modulator and the slave modulator to the first and second terminals of the circulator via the first and second switching devices, respectively, and to In an injection-locked modulation device that obtains the output of a main modulator or a slave modulator from a terminal, the first switch has two terminals, and a first terminal of the two terminals is connected to the main modulator. and the second
the terminal is connected to the first terminal of the circulator, the first terminal is terminated with the characteristic impedance of the line, and the second terminal is open or short-circuited, and the first and second terminals are directly connected. The second switch has two terminals, the first terminal of which is connected to the slave modulator, and the second switch has two terminals.
is connected to a second terminal of the circulator, the first terminal is terminated with the characteristic impedance of the line, and the second terminal is open or short-circuited, and the first and second terminals are directly connected. This is achieved by providing an injection-locked modulator characterized in that it has two modes.

(e) Embodiment of the invention FIG. 2 is a block connection diagram of an embodiment of the invention.

In the figure, 1 and 2 are a main modulator and a sub modulator, respectively, 7 and 8 are switchers, 5 is a circulator, and 6 is an output terminal.

Each of these blocks is connected as follows.

The main modulator 1 is connected to a terminal (1) of the circulator 5 via a switch 7, and the slave modulator 2 is connected to a terminal (3) of the circulator 5 via a switch 8.
The terminal (2) of the circulator 5 is connected to the output terminal 6.

The operation of the injection locking modulator connected in this manner is as follows.

The output of the main modulator 1 is applied to the sub modulator 2 via a switch 7, a circulator 5, and a switch 8.
Therefore, since the slave modulator 2 operates in synchronization with the main modulator 1, the power of the slave modulator 2 is taken out from the output terminal 6.

Here, when only the main modulator 1 is operated independently, the connection between the sub modulator 2 and the main modulator 1 is disconnected by the operation of the switch 8, but the sub modulator 2 has a resistance value equal to the characteristic impedance of the line. The main modulator 1 is connected to a circulator 5 whose terminal (3) is open or short-circuited. Therefore, the main modulator 1 and the sub modulator 2 are loaded with almost the same impedance as when they were injection-locked, so their operating states do not change.

FIG. 3 shows an example of the switching devices 7 and 8 shown in FIG.

In the figure, 11 is the input terminal, 12 is the output terminal,
13 and 14 are bias supply terminals, 15 is a variable resistor, 16, 17 and 18 are wire rings, and 19 and 20 are diodes, respectively.

These elements are connected as follows.

Input terminal 11 is a capacitor and diode 20
It is connected to the output terminal 12 via. The bias supply terminal 14 is grounded through a wire 18, a diode 20, and a wire 17, and the bias supply terminal 13 is grounded through a variable resistor 15, a wire 16, and a diode 19 connected to the capacitor.

The operation of the switch connected in this way is as follows.

In the same figure, apply 0V to bias supply terminal 13,
When a negative DC voltage is applied to each of the bias supply terminals 14 and a current flows through the diode 20, the diode 20 is turned on, and the high frequency signal input to the input terminal 11 is taken out to the output terminal 12.
Next, a negative DC voltage is applied to the bias supply terminal 13, and the variable resistor 15 is adjusted to set the current value so that the impedance of the diode 19 becomes the characteristic impedance of the line. Then, a positive DC voltage is applied to the diode 20 from the bias supply terminal 14 to turn off the diode 20.
state.

By doing this, the input terminal 11 is terminated with a characteristic impedance, and the impedance when looking at the diode 20 from the output terminal 12 appears to be infinite.

That is, this switch has two modes: a mode in which the input and output terminals are open, and a mode in which the slave modulator is loaded with a characteristic impedance, and a mode in which the input and output terminals are directly connected.

(f) Effect of the Invention As explained above, according to the present invention, when the slave modulator of the injection type synchronous modulator is disconnected, the slave modulator is loaded with characteristic impedance, while the main modulator is loaded with the circulator 5. A modulated high frequency signal is output from the terminal (2) of the circulator 5. Since the load impedances of these two modulators hardly change, each modulator operates stably as in the case of injection locking.

Furthermore, the modulator used in the present invention is low in price and has a simple structure, and uses a variable resistor in the bias circuit to control the current flowing through the diode, making the impedance seen from the input side variable. Therefore, the input impedance can be changed without affecting the high frequency characteristics, and it can be easily connected to a modulator with any impedance.

The operation when the main modulator is separated from the circulator 5 by the switch 7 and the output of the slave modulator which is not injected by the main modulator 1 is obtained from the output terminal 6 connected to the circulator 5 is also performed in the same manner as described above. I can explain.

[Brief explanation of the drawing]

FIG. 1 shows a conventional injection type synchronous modulation device, FIG. 2 shows an embodiment of the present invention, and FIG. 3 shows a more detailed connection diagram of the switch shown in FIG. 2. In the figure, 1 is the main modulator, 2 is the slave modulator, 5 is the circulator, 7 and 8 are the respective switchers, 6 and 12 are the output terminals, 11 is the input terminal, 13 and 14 is the bias supply terminal, 15
indicates a variable resistor, 16 to 18 indicate coils, and 19 and 20 each indicate a diode.

Claims (1)

[Claims] 1. The outputs of the main modulator and the sub modulator are
and the first of the circulator via the second switch.
and the second terminal, as well as the third terminal of the circulator.
In an injection-locked modulation device that obtains the output of the main modulator or the slave modulator from a terminal, the first switch has two terminals, and the first terminal of the two terminals is connected to the main modulator. a second terminal is connected to a first terminal of the circulator, the first terminal is terminated at a characteristic impedance of the line, the second terminal is connected to an open or shorted mode; The second switch has two terminals, and the first terminal of the two terminals is connected to the slave modulator. , a second terminal is connected to a second terminal of the circulator, the first terminal is terminated with a characteristic impedance of a line, and the second terminal is in an open or shorted mode; 1. An injection-locked modulator having two modes in which two terminals are directly connected.