JPS5851444B2 - Kotaihatsushinki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid state oscillator, and is particularly characterized by the provision of an improved frequency modulation circuit.

For example, when frequency modulating a solid-state oscillator in the microwave band using a Gunn effect element, the oscillation frequency changes when the bias voltage of the solid-state oscillator is changed. Changes in the oscillation frequency with respect to changes in voltage show diversity depending on variations in the solid-state oscillation element, the state of matching between the solid-state oscillation element and the three-dimensional circuit, and the like.

To avoid this, it is necessary to adjust the magnitude of the modulation signal in the modulator section to match the solid-state oscillator.

However, in terms of compatibility, complications cannot be avoided.

The present invention has been made to improve this, and will be described in detail below with reference to the drawings.

Figure 1 is an example of a schematic diagram of a solid-state oscillator, in which a solid-state oscillator element 1 consisting of a Gunn effect element or an invat element is attached to a waveguide housing 2 whose end is short-circuited, allowing direct current to pass through but high frequency. A bias voltage can be applied from a lead wire 4 through a choke portion 3 which is cut off.

The other end of the waveguide housing 2 is connected to a load (not shown) via a flange 5.

FIG. 2 shows an example of operating this solid-state oscillator.

When the bias voltage V is changed, the current 13 once reaches an extreme value and then gradually decreases, and the output 12 starts to rise after the current 13 reaches an extreme value, reaches its maximum value at a certain bias voltage, and then rapidly decreases. descend.

Figure 2a shows an example in which the oscillation frequency 11 decreases monotonically with the bias voltage .
This shows the case where an upwardly convex curve is drawn, showing diversity.

FIG. 3 shows a conventional example of obtaining a frequency modulated wave using a solid-state oscillator exhibiting such characteristics.

A DC voltage and a modulation signal are supplied from a DC power supply 21 and a modulation signal source 22 to a modulator 23, respectively, and a voltage obtained by superimposing a desired DC voltage and a desired modulation signal voltage is obtained as a modulator output.

The obtained voltage is supplied to the solid state oscillator 24 through the transmission line 25.

Since the characteristics of the solid-state oscillator are as shown in FIG. 2, the oscillation frequency of the solid-state oscillator 24 is frequency-modulated by the modulation signal by applying a bias voltage in which a modulation signal voltage is superimposed on a DC voltage.

The degree of frequency modulation of the solid-state oscillator 24 shows diversity as shown in the characteristic example of FIG. 2, and it is difficult to obtain uniform characteristics.

Therefore, the modulator 23 must be adjusted for each solid-state oscillator 24 to obtain the required frequency modulation degree.

This is unavoidably complicated when interchanging the solid-state oscillators 24.

If the solid-state oscillator 24 and the modulator 23 are integrated, there is no problem if they are compatible as a single unit, but if the solid-state oscillator 2
If the installation space for the transmission line 25 is narrow, or if one more transmission line 25 cannot be added, it is difficult to integrate the transmission line 25.

The present invention has been made in view of this problem, and is an attempt to solve this problem in a minimum space without increasing the number of lines.

FIG. 4 shows an embodiment of the present invention, and parts having the same functions as those in FIG. 3 are denoted by the same reference numerals, and explanations thereof will be omitted.

A bias voltage obtained by superimposing a modulation signal voltage on the required DC voltage obtained from the modulator 23 is guided to the branch point 30 via the transmission line 25.

From the branch point 30, one side is connected to a low-pass filter or band-stop filter 26, and the other side is connected to a high-pass filter or band-stop filter 27.

It is connected to the latter and connected again to a branch point 31 on the output side of the filter 26 via a modulation signal amplitude adjuster 28 consisting of an amplifier or an attenuator, and then to the solid-state oscillator 24.

Therefore, the filter 26, 27 and the modulating signal amplitude adjuster 28
If it is integrated with the solid-state oscillator 24, even if the modulation signal voltage superimposed on the modulator output is kept constant, it can be optimally adjusted for each solid-state oscillator 24 in the modulation signal amplitude adjuster 28, which eliminates compatibility problems. There is no need to increase the number of transmission lines.

In the above description, the solid-state oscillator 24 is equipped with only a solid-state oscillation element, but it is also possible to use a solid-state oscillator 24 with a solid-state oscillation element and a varactor diode.

FIG. 5 shows an example of a solid-state oscillator 33 having a varactor diode, in which a varactor diode 6 is added to the solid-state oscillator 24 of FIG.

One end of this varactor diode 6 is connected to the waveguide housing 2, and the other end is connected to a lead wire 8 via a choke 7.

If a constant DC voltage is applied to the solid-state oscillation element 1 through the lead wire 4, and a tuning voltage T (DC) is applied to the varactor diode 6 through the lead wire 8, oscillation will occur at a frequency of 11 as shown in FIG. Output 12 changes.

Therefore, if a modulation signal is applied as the tuning voltage (1), the oscillation frequency will be frequency-modulated by the modulation signal.

FIG. 7 shows an example in which the present invention is implemented in a solid-state oscillator 33 having a varactor diode as shown in FIG.

A bias voltage in which a modulation signal voltage is superimposed on a required DC voltage sent from the modulator 23 via the transmission path 25 is branched at a branch point 30, and one is passed through a low-pass filter or band-elimination filter 26. Only the DC voltage is selected and applied to the solid state oscillation element 1, and the other voltage is applied to the varactor diode 6 through the level adjustment circuit 29.

Since a modulation signal superimposed on a DC voltage must be applied to the varactor diode 6, a filter is not necessary.

FIG. 8 shows another embodiment of the present invention in which a solid state oscillator 33 having a varactor diode is used.
The DC voltage superimposed on the modulated signal transmitted is at the branch point 30.
On one side, the modulation signal is blocked by a low-pass filter or band-elimination filter 26, and only the DC voltage is applied to the solid-state oscillation element.

The other is passed through a high-pass filter or bandpass filter 27 to cut off the DC voltage and take out only the modulated signal, and then passed through a modulated signal amplitude adjustment circuit 28 to adjust it to obtain the desired degree of frequency modulation. Apply to F'6.

It is preferable to apply a DC voltage to the varactor diode 6 in order to stabilize the oscillation and increase the oscillation output. Through the filter 26, the amplitude adjustment circuit 2
It is applied to the varactor diode 6 at the same time as the modulation signal of the output of 8.

It goes without saying that a capacitor may be simply used as the high-pass filter or bandpass filter 27 in the present invention, and various other separation means may also be used.

As described above, according to the present invention, the degree of frequency modulation can be easily adjusted according to the characteristics of the solid-state oscillator without increasing the number of transmission lines, so there is no problem with compatibility, and the industrial effect is extremely significant. There is something.

Needless to say, the idea of the present invention is not limited to the embodiments described herein.

[Brief explanation of drawings]

1 and 2 are a schematic diagram and a characteristic curve diagram of a solid-state oscillator for explaining an embodiment of the present invention, respectively. FIG. 3 is a block diagram of a conventional example, and FIG. 4 is an embodiment of the present invention. 5 and 6 are schematic diagrams and characteristic curve diagrams of a solid-state oscillator for explaining other embodiments of the present invention, respectively. It is a block diagram showing an example. In the drawings, 1 is a solid-state oscillator, 2 is a waveguide housing, 3 is a high-frequency choke, 4 is a lead wire, 5 is a waveguide flange, 6 is a varactor diode, and 7 is a high-frequency choke.
8 is a lead wire, 11.1213 is a curve showing changes in frequency, output, and current, 21 is a DC power supply, 22 is a modulation signal source, 23 is a modulator, 24 is a solid-state oscillator having only solid-state oscillation elements, and 25 is a solid-state oscillator. A transmission line, 26 a low-pass filter or band-stop filter, 27 a high-pass filter or bandpass filter, 28 a modulation signal amplitude adjuster, 29 a level adjustment circuit, and 33 a solid-state oscillation element. It is a solid-state oscillator that has both a varactor diode and a varactor diode.

Claims (1)

[Claims] 1. An input terminal that inputs a signal in which a modulation signal is superimposed on a DC voltage, a circuit that is connected to this input terminal and separates the DC voltage and the modulation signal, and a circuit that adjusts the amplitude of the separated modulation signal. A solid-state oscillator characterized in that a DC voltage and a modulation signal are separated within the oscillator, and the amplitude of the separated modulation signal can be adjusted within the oscillator. .