JP3515475B2 - Phase locked oscillator and output circuit of oscillator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase-locked oscillator and an output circuit of an oscillator for reducing the influence of load fluctuation and output fluctuation due to temperature fluctuation.

[0002]

2. Description of the Related Art FIG. 8 shows a circuit configuration of a conventional phase locked oscillator. In the figure, 101 is a voltage controlled oscillator, 102 is a directional coupler, 103 is a phase comparator, 1
04 is a low pass filter, 105 is a reference oscillator, 106
Is a load, 1021 is an input terminal of the directional coupler 102, 1
Reference numeral 022 is an output terminal of the directional coupler 102, 1023 is a coupling terminal of the directional coupler 102, 110 is a load, and 115 is an isolation amplifier. The conventional phase-locked oscillator is configured as described above, the phase of the output signal of the voltage controlled oscillator 101 and the output signal of the reference signal oscillator 105 are compared, the frequency of the voltage controlled oscillator 101 is controlled by the output, and the output signal is loaded. It was supplied to 106.
In order to reduce the effect of load fluctuation, the voltage controlled oscillator 101
The isolation amplifier 115 or the attenuator is inserted between the directional coupler 102 and the directional coupler 102 to reduce the amount of coupling between the voltage controlled oscillator 101 and the load 106.

[0003]

Since the conventional phase-locked oscillator is constructed as described above, there is a problem that the isolation amplifier 115 is required, the circuit becomes complicated and the power consumption increases. In addition, there is also a problem of output fluctuation with respect to temperature fluctuation.

[0004] This invention has been made to solve the above problems, reduce the influence of load variation, an object of Rukoto obtain the phase synchronization oscillator which aimed to reduce the output variation due to temperature variation.

[0005]

A phase-locked oscillator according to the present invention is a voltage-controlled oscillator, a reference signal oscillator, and a phase comparison for performing a phase comparison between an output signal of the voltage-controlled oscillator and an output signal of the reference signal oscillator. And a low-pass filter for limiting the band of the output signal of the phase comparator, the first line and the second line are coupled by a distributed constant circuit, and the first terminal of the first line is input. A terminal, a second terminal as an output terminal, a first terminal at one end facing the input terminal of the second line , a coupling terminal, and a second terminal at the other end of the second line end to Rutoto the terminal as the isolation terminal
Connect the output of the voltage controlled oscillator to the input terminal.
Directional coupler and the electric current connected to the coupling terminal.
In phase-locked oscillator with load of pressure controlled oscillator
And the directional coupler includes the first line and the second line.
Fluctuations due to temperature changes in the amount of coupling between the
Change in the output level of the voltage controlled oscillator due to
I tried to erase it.

Further, a voltage controlled oscillator, a reference signal oscillator, a phase comparator for performing phase comparison between the output signal of the voltage controlled oscillator and the output signal of the reference signal oscillator, and band limitation of the output signal of the phase comparator. And a low-pass filter for performing the first line and the second line are coupled by a distributed constant circuit,
The first terminal of the first line is used as an input terminal, the second terminal is used as an output terminal, and is opposed to the input terminal of the second line.
The first terminal in the position
Use the second terminal at the other end as an isolation terminal.
And the output of the voltage controlled oscillator to the coupling end.
Directional coupler connected to the child and the output terminal.
Phase-locked oscillation with a load of the voltage controlled oscillator
The directional coupler includes the first line and the directional coupler.
The fluctuation due to the temperature change of the coupling amount with the second line is
Change in output level of the voltage controlled oscillator due to temperature change
It was designed to cancel the movement.

Further, it is provided between the directional coupler and the load.
The side-coupling filter is provided, the passage loss fluctuation due to the temperature change of the side-coupling filter is
Of the output level of the voltage controlled oscillator due to
Combine with output level fluctuation due to temperature change of directional coupler.
The temperature compensation is performed by setting the relationship between the characteristics of the side-coupling filter and the oscillation frequency of the voltage controlled oscillator so as to change in the opposite direction with respect to the variation.

Further, the output circuit of the oscillator according to the present invention is the output circuit of the oscillator for guiding the output signal of the oscillator to the load through the directional coupler , wherein the directional coupler has its input
A first line provided with a force terminal and a coupling terminal provided
The distance from the second terminal is changed according to the temperature change,
The amount of coupling between the input terminal and the coupling terminal is changed .

Further, in the output circuit of the oscillator to guide the output signal of the oscillator to the load through the side coupled filter, pass loss variation due to temperature change of the side coupled filter is, the temperature
To change in opposite directions with respect to the variation of the output level of the oscillator by degrees change, before and characteristics of the side coupled filter
The temperature compensation is performed by setting the relationship of the oscillation frequency of the oscillator .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. The first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 is a voltage controlled oscillator, 2 is a distributed constant circuit in which the first line and the second line are coupled, the first terminal of the first line is an input terminal 21, and the second terminal is an output terminal. 22, a directional coupler terminating the first terminal at a position facing the input terminal 21 of the second line as a coupling terminal 23 and the second terminal as an isolation terminal, and 3 are the voltage controlled oscillator 1 2 is a low-pass filter, 5 is a reference oscillator, and 6 is a load.

In the conventional example shown in FIG. 7, the voltage controlled oscillator 1
The directional coupler 102 and the isolation amplifier 115 are provided between 01 and the load 106 to secure the required isolation and reduce the influence of the load. On the other hand, in the configuration of the present invention, the connection method of the directional coupler 2 inserted between the voltage controlled oscillator 1 and the load 6 is changed to 10d.
The required isolation of about B or more is ensured. As a result, the circuit configuration is not complicated and power consumption can be reduced.

When PLL control is performed with a signal obtained by performing phase comparison in a low frequency band and the multiplied output of the voltage controlled oscillator is used as a desired wave, the directional coupler 2 is used as shown in FIG. By setting the center frequency of the pass band of 1 to an integral multiple of the oscillation frequency of the voltage controlled oscillator 1, it is possible to reduce the leakage of harmonics and unnecessary waves output from the voltage controlled oscillator 1 to the output. In particular, since the frequency component lower than the desired wave can be reduced, there is also an effect that the oscillation operation can be stabilized by being returned to the voltage controlled oscillator 1 by the reflection of the fundamental wave generated at a strong level.

Further, as shown in FIG. 3B, the coupling amount of the directional coupler 2 is controlled so as to change with a temperature change,
The output characteristic of the voltage controlled oscillator is compensated.
That is, as shown in FIG. 3A, an isolation terminal in which a first line (input terminal 21 to output terminal 22) and a second line (coupling terminal 23 to terminator 241) of the directional coupler are connected. 24) the amount of coupling between the first line and the second line
The line spacing is changed to control the amount of coupling to perform temperature compensation.

Embodiment 2. Next, the second embodiment will be described. FIG. 4 is a configuration diagram according to the second embodiment. In FIG. 4, the same reference numerals as those in FIG. 1 indicate the same contents or functions. The components are the same as in the case of FIG. 1, but the connections between the directional coupler 2 and the voltage controlled oscillator 1 and the load 6 are different. That is, the coupling terminal 23 of the directional coupler 2 is connected to the output of the voltage controlled oscillator 1, the output terminal 22 is connected to the load 6,
The input terminal 21 is connected to the phase comparator 3 via the attenuation circuit 7. With such a connection, the output is reduced as compared with the first embodiment, but the fluctuation of the oscillation characteristic of the voltage controlled oscillator 1 due to the load fluctuation is reduced.

Embodiment 3. Next, a third embodiment will be described. FIG. 5 is a configuration diagram according to the third embodiment. In FIG. 5, the same reference numerals as those in FIGS. 1 and 4 denote the same contents or functions.
In FIG. 5, the microstrip 81 shown in FIG. 6A as an example is side-coupled between the directional coupler 2 and the load 6 with a width W, a shift amount L, and an interval S to provide a microstrip-side coupling filter 8. Is inserted and the change in the output frequency of the voltage controlled oscillator 1 is compensated for by utilizing the change in the pass frequency characteristic due to the temperature. That is, since the temperature characteristic of the microstrip-side coupling filter 8 changes as shown in FIG. 6B, the change amount of the passage loss depending on the temperature is the change amount required to cancel the output fluctuation of the voltage controlled oscillator 1. Temperature compensation can be performed by setting a desired frequency at a frequency position where Also, as seen in FIG. 6 (B),
Since the selection curve of the filter moves substantially parallel to the frequency axis with temperature, it has a feature that either a positive fluctuation rate or a negative fluctuation rate can be obtained by setting the frequency position.

Fourth Embodiment Next, a fourth embodiment will be described. FIG. 7 is a configuration diagram according to the fourth embodiment. In FIG. 7, the same reference numerals as those in FIGS. 1, 4 and 5 indicate the same contents or functions. 8 side coupled filter, 9 is an oscillation frequency temperature compensation circuit for performing temperature compensation necessary to control the control voltage of the voltage controlled oscillator. Frequency variation of the voltage controlled oscillator 1 is as oscillation <br/> performs compensation by frequency temperature compensation circuit 9, similarly to compensate Ri by the side coupled filter 8 output level variation of the third embodiment . As described above, when the signal source is the above-mentioned synchronous oscillator, the one that controls the temperature characteristic by changing the line spacing of the directional coupler and the one that compensates the temperature characteristic by utilizing the temperature change of the filter characteristic are explained above. However, the present invention is not limited to this, and can be used for the purpose of compensating the output level of the high frequency oscillator accompanied by temperature fluctuation.

[0017]

As described above, the phase-locked oscillator according to the present invention is provided with the first voltage-controlled oscillator between the voltage-controlled oscillator and the load.
The line and the second line are connected by a distributed constant circuit, the first terminal of the first line is the input terminal, the second terminal is the output terminal, and the position facing the input terminal 7 of the second line. A directional coupler terminating at the first terminal as the coupling terminal and the second terminal as the isolation terminal, and connecting the output of the voltage controlled oscillator to the input terminal of the directional coupler and the load to the coupling terminal. In addition, since the center frequency of the directional coupler is set to an integral multiple of the oscillation frequency of the voltage controlled oscillator, the effect of removing unnecessary waves can be obtained. In addition, since reflection is particularly large with respect to the fundamental frequency component of the voltage controlled oscillator, and in particular, the frequency component lower than the desired wave can be reduced, the oscillation of the fundamental wave component generated at a strong level is reflected back to the voltage controlled oscillator. There is also an effect that the operation can be stabilized. Further, since the coupling amount of the directional coupler is changed corresponding to the temperature change, there is an effect that the temperature compensation can be performed without requiring an additional circuit. It should be noted that the temperature compensation method of changing the coupling amount of the directional coupler in accordance with the temperature change can be applied regardless of the type of the oscillator to obtain the same effect.

The phase locked oscillator according to the present invention is
The first line and the second line are coupled by a distributed constant circuit between the voltage-controlled oscillator and the load, the first terminal of the first line is an input terminal, and the second terminal is an output terminal. A directional coupler that terminates the first terminal at a position facing the input terminal 7 of the line 2 as a coupling terminal and the second terminal as an isolation terminal, and outputs the output of the voltage controlled oscillator to the coupling terminal, Since the load is connected to the output terminal and the center frequency of the directional coupler is an integral multiple of the oscillation frequency of the voltage controlled oscillator, the effect of removing unnecessary waves can be obtained. In addition, since reflection is particularly large with respect to the fundamental frequency component of the voltage controlled oscillator, and in particular, the frequency component lower than the desired wave can be reduced, the oscillation of the fundamental wave component generated at a strong level is reflected back to the voltage controlled oscillator. There is also an effect that the operation can be stabilized. Further, since the coupling amount of the directional coupler is changed corresponding to the temperature change, there is an effect that the temperature compensation can be performed without requiring an additional circuit. It should be noted that the temperature compensation method of changing the coupling amount of the directional coupler in accordance with the temperature change can be applied regardless of the type of the oscillator to obtain the same effect.

Further, since the frequency characteristic of the directional coupler is changed in accordance with the temperature change, there is an effect that temperature compensation can be performed without requiring an additional circuit. It should be noted that the temperature compensation method of changing the frequency characteristic of the directional coupler in accordance with the temperature change can be applied regardless of the type of oscillator to obtain the same effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a diagram illustrating frequency characteristics of a directional coupler.

FIG. 3 is a diagram illustrating control of a temperature characteristic of a coupling amount of a directional coupler.

FIG. 4 is a configuration diagram of a second embodiment.

FIG. 5 is a configuration diagram of a third embodiment.

FIG. 6 is a diagram illustrating a structure of a side coupling type bandpass filter and control of temperature characteristics.

FIG. 7 is a configuration diagram of a fourth embodiment.

FIG. 8 is a configuration diagram of a conventional example.

[Explanation of symbols]

1 voltage controlled oscillator, 2 directional coupler 21 input terminal, 22 output terminal, 23 coupling terminal, 3
Phase comparator, 4 low pass filter, 5 reference oscillator, 6 load, 7 subtraction circuit, 8 side coupling filter, 9 oscillation frequency temperature compensation circuit.

Continuation of the front page (56) Reference JP-A-8-307262 (JP, A) JP-A-2-141106 (JP, A) JP-A-3-283701 (JP, A) JP-A-52-6058 (JP , A) JP 5-235601 (JP, A) JP 9-284013 (JP, A) JP 2-62120 (JP, A) US Patent 4041416 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H03L 7/08 H03B 5/04

Claims (5)

(57) [Claims] 1. A voltage controlled oscillator, a reference signal oscillator,
A phase comparator that performs phase comparison between the output signal of the voltage controlled oscillator and the output signal of the reference signal oscillator, a low-pass filter that limits the band of the output signal of the phase comparator, a first line and a second line. The first line of the first line is an input terminal, the second terminal of the first line is an output terminal, and the first line of the second line is connected to the input terminal of the second line at an end facing the input terminal. To the coupling terminal, the other end of the second line
It terminates certain second terminal as isolated terminal
Also connect the output of the voltage controlled oscillator to the input terminal.
Connected directional coupler and connected to the coupling terminal before
The phase-locked oscillator with the load of the voltage controlled oscillator
The directional coupler includes the first line and the second line.
The change in the amount of coupling between the
To cancel the fluctuation of the output level of the voltage controlled oscillator
A phase-locked oscillator characterized in that 2. A voltage controlled oscillator, a reference signal oscillator,
A phase comparator that performs phase comparison between the output signal of the voltage controlled oscillator and the output signal of the reference signal oscillator, a low-pass filter that limits the band of the output signal of the phase comparator, a first line and a second line. Position of the first line of the first line as an input terminal and the second terminal of the second line as an output terminal, and the line is connected to the input terminal of the second line.
The first terminal at the coupling terminal, the other end of the second line
Terminate a second terminal as an isolation terminal
And connect the output of the voltage controlled oscillator to the coupling terminal.
A continuous directional coupler and a load of the voltage controlled oscillator connected to the output terminal.
In the phase-locked oscillator having, the directional coupler includes the first line and the second line.
The change in the amount of coupling between the
To cancel the fluctuation of the output level of the voltage controlled oscillator
A phase-locked oscillator characterized in that 3. A device provided between the directional coupler and a load.
With a side-coupled filter, the passage loss variation due to the temperature change of the side-coupled filter causes
Due to the fluctuation of the output level of the voltage controlled oscillator and the direction
Combine with output level fluctuation due to temperature change of the sex coupler
The temperature compensation is performed by setting the relationship between the characteristic of the side-coupling filter and the oscillation frequency of the voltage-controlled oscillator so that the temperature variation is performed in the opposite direction. The phase-locked oscillator according to claim 1 or 2 . 4. An oscillator output circuit for guiding an output signal of an oscillator to a load through a directional coupler, wherein the directional coupling is provided.
Is a first line with its input terminal and a coupling terminal
The space between the second terminal provided with the
Change the amount of coupling between the input terminal and the coupling terminal
The output circuit of the oscillator, characterized in that it comprises a temperature compensation means Ru changing the. 5. In an oscillator output circuit for guiding an output signal of an oscillator to a load through a side-coupling filter, fluctuations in passage loss due to a temperature change of the side-coupling filter are caused by the temperature change.
To change in opposite directions with respect to the variation of the output level of the oscillator by reduction, the characteristic of the side coupled filter onset
An output circuit of an oscillator, wherein temperature compensation is performed by setting a relationship between oscillation frequencies of the oscillator .