JPH10178316A - Oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve electrical characteristics and to prevent the deterioration of oscillation output in frequencies by switching two oscillation circuits and amplifying their signals by a common amplifier circuit. SOLUTION: A switching signal Vsw is supplied to a switching circuit 3 from the outside to supply a signal from the circuit 3 to respective oscillation circuits A and B to oscillate the circuit A, e.g. and to suppress the oscillation of the circuit B. The frequency signal of a high frequency oscillated by the circuit A is supplied for the emitter of the transistor TR 1 of the amplifier circuit 2 to be amplified by the transistor TR1 to output the frequency signal of the high frequency from the circuit A as an output signal from a collector. On the other hand, the polarity of the signal Vsm to the circuit 3 from outside is reversed to oscillate the circuit B, e.g. and to suppress the oscillation of the circuit A. The frequency signal of the high frequency oscillated by the circuit B is supplied for the emitter of the transistor TR 1 of the amplifier circuit 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator for switching an oscillation frequency.

[0002]

2. Description of the Related Art Conventionally, when a high-frequency oscillator switches its oscillation frequency (for example, 800 MHz), the capacitance of the oscillating portion of the oscillator is switched by an active element using one oscillator to obtain a desired oscillation frequency, or There is a method in which the two resonators of the above are switched by an active element to obtain an oscillation frequency of a desired resonance frequency.

[0003]

In the former method of switching the capacitance, since one oscillator is shared, it is difficult to design the constant of the oscillator to an optimum ideal constant at an arbitrary oscillation frequency. If the range of the oscillation frequency is too narrow, or if the range of the oscillation frequency at which oscillation can be performed is widened, high output cannot be obtained.

In the latter method of switching between two resonators of one oscillator, there is a limit to a range of an oscillating frequency that can be supported, and a stable output signal is obtained at substantially the same output signal level over the entire range of a wide frequency band. Is difficult to maintain. Therefore, as shown in FIG. 5, the output A of the oscillation unit A and the amplification unit A and the output B of the oscillation unit B and the amplification unit B are output.
And it is necessary to maintain a stable output at substantially the same output signal level over the entire range of the frequency of the wide band. In addition to the oscillation units A and B, the amplification units A and B There is a problem that each of them is required individually and independently, and the circuit scale becomes large.

[0005] The present invention solves these problems,
Switching between two oscillator circuits, amplifying the signal with a common amplifier circuit, and adding a matching circuit to stabilize the oscillation to improve the electrical characteristics and prevent the oscillation output from decreasing between frequencies. And

[0006]

Means for solving the problem will be described with reference to FIGS. 1, 3 and 4. Figure 1,
3 and 4, oscillation circuits A and B are circuits for generating different high-frequency signals.

The amplifier circuit 2 amplifies and outputs the frequency signal of one of the two oscillation circuits A and B.
An output matching circuit section is provided. Switching circuit 3
Is for oscillating either the oscillation circuit A or the oscillation circuit B, stopping the other oscillation, supplying only one frequency signal to the amplifier circuit 2, and synchronizing with the output matching circuit section of the amplifier circuit 2. The oscillation frequency is switched.

Next, the operation will be described. As shown in FIG. 1, the switching circuit 3 switches either the first frequency signal or the second frequency signal from the oscillation circuit A as the first oscillation circuit or the oscillation circuit B as the second oscillation circuit. To the amplifier circuit 2, and the one amplifier circuit 2 amplifies and outputs the amplified signal.

As shown in FIG. 3, an output matching circuit section is provided at an output stage of one amplifier circuit 2 to perform matching in synchronization with a first frequency signal or a second frequency signal.
The output signal is prevented from lowering.

[0010] As shown in FIG. 4, a varicap diode is used as an element to be matched in the output matching circuit section. Therefore, two oscillation circuits 1
And a high frequency signal is amplified by the common amplifier circuit 2 and a matching circuit is added.
It is possible to stabilize the oscillation of the high-frequency signal, improve the electrical characteristics, and prevent the oscillation output from decreasing between frequencies.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the concept of the present invention will be described with reference to FIG. FIG. 2 is a conceptual explanatory diagram of the present invention.

In FIG. 2, one of the oscillating circuits A and B outputs a high frequency signal A or B to one common amplifier circuit 2 in response to a switching signal.

Amplifying circuit 2 is one amplifying circuit shared by two oscillating circuits A and B. A high frequency signal A or a frequency signal from either one of two oscillating circuits A or B is used. The signal B is amplified and output.

As described above, the oscillation circuit A and the oscillation circuit B are independently provided, so that a high frequency can be oscillated stably, and the two oscillation circuits A and B
By amplifying one of the high frequency signals from the common amplifier circuit, the circuit configuration can be simplified and different frequency signals A or B can be output as output signals. The details will be sequentially described below.

Next, the embodiment and operation of the present invention will be sequentially described in detail with reference to FIG. 1, FIG. 3 and FIG. FIG.
Shows an example of a circuit according to an embodiment of the present invention.

In FIG. 1, an oscillating circuit 1 oscillates a high-frequency signal. Here, an oscillating circuit A and an oscillating circuit B are provided, and one of them is oscillated by a signal from a switching circuit 3. Then, the signal is supplied to one amplifier circuit 2. The oscillating circuits A and B are adapted to input a signal from the switching circuit 3 to the base of the transistor as shown in the figure, and to switch between the oscillation state and the oscillation stop state.

The amplifying circuit 2 amplifies a high-frequency signal oscillated by either the oscillating circuit A or the oscillating circuit B by the transistor TR1 and outputs it as an output signal. The switching circuit 3 supplies a signal to both the oscillating circuit A and the oscillating circuit B in response to an external switching signal Vsw to oscillate either one of the oscillating circuits A and B. A signal is supplied to the emitter of one amplifier circuit 2.

Next, the operation will be described. First, a switching signal Vsw is externally supplied to the switching circuit 3 so that the switching circuit 3
Supplies a signal to the oscillation circuit A and the oscillation circuit B respectively, for example, oscillates the oscillation circuit A and suppresses oscillation of the oscillation circuit B. The high-frequency signal oscillated by the oscillation circuit A is supplied to the emitter of the transistor TR1 of the amplifier circuit 2, amplified by the transistor TR1, and the high-frequency signal from the oscillation circuit A is output from the collector as shown in FIG. Output.

Second, the switching signal V is externally supplied to the switching circuit 3.
The polarity of sw is inverted (for example, from 0 level to 1 level), and a signal is supplied from the switching circuit 3 to each of the oscillation circuits A and B. For example, the oscillation circuit B is oscillated. Deter. The high frequency signal oscillated by the oscillation circuit B is supplied to the emitter of the transistor TR1 of the amplifier circuit 2,
The signal is amplified by 1 and a high-frequency signal from the oscillation circuit B is output from the collector as an output signal as shown in the figure.

Third, the first and second steps are repeated so that high-frequency signals are switched at high speed. At this time, the oscillation frequency is stabilized by switching the capacitance of the resonance part of the oscillation circuit A or the oscillation circuit B on the side where oscillation is suppressed by a signal (not shown), and switching the frequency alternately to any value. The output may be changed.

As described above, the high-frequency oscillation frequency signal is switched by alternately switching the two oscillation circuits A and B, supplying the high-frequency signal to one amplifier circuit 2, amplifying and outputting the same. This makes it possible to stabilize the oscillation at that time to improve the electrical characteristics, and in particular to improve the phase noise.

FIG. 3 shows another embodiment of the present invention.
Here, the oscillation circuit A and the oscillation circuit B are the same as the oscillation circuit A and the oscillation circuit B in FIG. In FIG. 3, a high frequency signal oscillated by either the oscillation circuit A or the oscillation circuit B is supplied to a transistor T.
The signal is amplified by R1 and output as an output signal. Here, an output matching circuit is added to the output stage.

The output matching circuit adjusts the capacitance so that the output impedance matches the high-frequency signal A or the frequency signal B from the oscillation circuit A or the oscillation circuit B, and is described in FIG. Circuit. By adding this output matching circuit section to the output stage of the amplifier circuit 2, the frequency signal A is converted to the frequency signal B, or vice versa.
, The output signal Pout is prevented from lowering by adjusting the capacitance, and can be kept substantially constant.

The switching circuit 3 is provided with an external switching signal Vsw.
A signal is supplied to both the oscillating circuit A and the oscillating circuit B to cause one of them to oscillate, and the high-frequency signal from the oscillating circuit A or the oscillating circuit B
The output signals are supplied to the emitters of the two amplifier circuits 2 and synchronized with the frequency signal A or the frequency signal B as shown in the circuit diagram of FIG. And the output impedance are matched to prevent the output signal Pout from lowering.

Next, the operation will be described. First, a switching signal Vsw is externally supplied to the switching circuit 3 so that the switching circuit 3
Supplies a signal to the oscillation circuit A and the oscillation circuit B respectively, for example, oscillates the oscillation circuit A and suppresses oscillation of the oscillation circuit B. The high-frequency signal oscillated by the oscillating circuit A is supplied to the emitter of the transistor TR1 of the amplifier circuit 2, amplified by the transistor TR1, and output to an additional output matching circuit portion of the collector shown in the figure. The output matching circuit adjusts and matches the output impedance of the high frequency signal A from the oscillation circuit A in synchronization with the signal from the switching circuit 3, and outputs a substantially constant level of the high frequency from the oscillation circuit A as an output signal. Is output.

Second, the switching signal V is externally supplied to the switching circuit 3.
The polarity of sw is inverted (for example, from 0 level to 1 level), and a signal is supplied from the switching circuit 3 to each of the oscillation circuits A and B. For example, the oscillation circuit B is oscillated. Deter. The high frequency signal oscillated by the oscillation circuit B is supplied to the emitter of the transistor TR1 of the amplifier circuit 2,
The signal is amplified by 1 and output to the added output matching circuit section of the collector shown in the figure. The output matching circuit unit adjusts and matches the output impedance of the high frequency signal B from the oscillation circuit B in synchronization with the signal from the switching circuit 3 and outputs a substantially constant level of the high frequency from the oscillation circuit B as an output signal. Is output.

Third, the first and second steps are repeated to switch the high frequency signal at high speed, and the output matching circuit section added to the amplifier circuit 2 matches the oscillation frequency with the output impedance in synchronization with the switching signal. Then, a constant output signal Pout is output even when a high frequency signal is switched. At this time, the oscillation frequency is stabilized by switching the capacitance of the resonance part of the oscillation circuit A or the oscillation circuit B on the side where oscillation is suppressed by a signal (not shown), and switching the frequency alternately to any value. The output may be changed.

As described above, the two oscillating circuits A and B are alternately switched, the high frequency signal is supplied to one amplifier circuit 2 and amplified, and the output matching circuit section added to the amplifier circuit 2 performs the amplification. Oscillation frequency and output impedance are matched in synchronization with the switching signal, and a constant output signal Pout is output even when the high-frequency signal is switched, thereby stabilizing oscillation when the high-frequency oscillation frequency signal is switched. It is possible to improve the electrical characteristics, and particularly to improve the phase noise, and furthermore, even if the frequency of the high-frequency signal changes, the output signal Pou at a substantially constant level
t can be output.

FIG. 4 shows an example of a circuit diagram in which a varicap diode is added to the output matching circuit section of the present invention. This is an example of a specific circuit of the output matching circuit unit in FIG. 3, and the area inside the dotted rectangle corresponds to the output matching circuit unit in FIG. 3.

In FIG. 4, BD is a varicap diode (variable capacitance diode), which changes to a predetermined capacitance according to a voltage applied by a control signal (a or b) shown in FIG.

TR1 is a transistor and corresponds to TR1 in FIG. 3 and amplifies either the high frequency signal A or the high frequency signal B from the oscillation circuit A or the oscillation circuit B.

Next, the operation will be described. The control signal (a or b) shown on the left side in FIG. 4 divides the voltage output from the buffer by the resistors R1 and R2, and applies the divided voltage to the varicap diode BD as a reverse voltage. Varicap diode BD at that time
Connects the capacitance determined by the variable capacitance and the capacitance C3 of the varicap diode BD to the collector of the transistor TR1, and connects the capacitance C connected to the collector.
1, impedance matching determined by C2, and matching to a high frequency signal A or frequency signal B from either the oscillation circuit A or the oscillation circuit B. However, this is for outputting an output signal Pout of a substantially constant level.

[0033]

As described above, according to the present invention,
Since a configuration is adopted in which the two oscillating circuits 1 are switched to amplify the high frequency signal by the common amplifier circuit 2 and add a matching circuit, the oscillation of the high frequency signal is stabilized and the electrical characteristics are improved. While being able to
It is possible to prevent the oscillation output from decreasing between the switched frequencies. These have made it possible to:

(1) By providing two oscillation circuits 1, two oscillation frequencies can be set (designed) independently and can be easily set (designed) to an arbitrary oscillation frequency. Further, the electrical characteristics of the oscillator for oscillating a plurality of high frequency signals can be stabilized, and in particular, the phase noise can be improved.

(2) By amplifying the high frequency signal from the two oscillation circuits 1 with one amplification circuit 2,
The number of circuit elements can be reduced and the oscillator can be downsized. (3) By providing two oscillation circuits 1, a plurality of arbitrary high-frequency signals can be set, and an oscillator having a high frequency, a wide band, and good output stability can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit example of one embodiment of the present invention.

FIG. 2 is a conceptual explanatory diagram of the present invention.

FIG. 3 is another circuit example of the present invention.

FIG. 4 is a circuit diagram example in which a varicap diode is added to the output matching circuit unit of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1: Oscillator circuit 2: Amplifier circuit 3: Switching circuit BD: Varicap diode R1, R2: Resistance C1, C2, C3: Diode TR1: Transistor

Claims (3)

[Claims] 1. An oscillator for switching an oscillation frequency, comprising: a first oscillation circuit that oscillates a predetermined first frequency signal; a second oscillation circuit that oscillates a predetermined second frequency signal; An oscillator circuit or one amplifier circuit for amplifying and outputting the frequency signal from the second oscillator circuit. 2. An output matching circuit section is provided at an output stage of said one amplifier circuit, and said first frequency signal or said second frequency signal is synchronized with a switching signal of said first frequency signal or said second frequency signal. 2. The oscillator according to claim 1, wherein the oscillation frequency of the second frequency signal and the output impedance are matched to suppress a decrease in the output signal. 3. The oscillator according to claim 2, wherein said matching element is a varicap diode.