JPH10242849A - Voltage controlled high-frequency oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably derive two oscillation output signals by one control circuit by outputting a fundamental signal of specific frequency outputted from an oscillation circuit including a resonance circuit part operating with a frequency control voltage and a frequency band switch voltage adjusted by a voltage control circuit part according to the frequency of the fundamental signal to be outputted and the multiplied frequency of the fundamental signal. SOLUTION: The resonance circuit part A1 of the oscillation circuit A outputs the fundamental oscillation signal X of specific frequency f1 according to the control voltage VT, and it is amplified by an amplifier circuit A3 to derive an output signal y1 . At the same time, the fundamental oscillation signal X is inputted to a multiplier circuit part B and multiplied as specified, and a frequency f2 is output as a 2nd output signal y2 through a filter part C. A voltage control circuit part D monitors the oscillation output signals y1 and y2 according to the fundamental oscillation signal X. A PLL-IC circuit D1 compares the actual frequency with a desired frequency and changes a signal of the phase difference into a DC voltage as the control voltage Vt through a L.P.F circuit D2 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage-controlled high-frequency oscillation circuit capable of deriving two oscillation output signals in different bands.

[0002]

2. Description of the Related Art Hitherto, a voltage-controlled high-frequency oscillation circuit used for a transmission oscillator of a mobile communication device or another communication device and a local oscillator of a receiver has been known.

Recently, various mobile communication devices such as mobile phones and car phones have become widespread, and in some communication systems, the shortage of the number of channels has become serious. New systems are in operation to solve these problems. That is,
Even in the same area, a system having a carrier frequency with a different band is introduced, and a communication device capable of supporting a plurality of systems requires an oscillator capable of generating a plurality of oscillation output signals corresponding to these carrier frequencies. To cope with this, it is conceivable to use a plurality of oscillators corresponding to each system in one mobile communication device. In addition, it is conceivable that an oscillation frequency corresponding to each system is derived by controlling a control voltage by using an oscillator having one voltage-controlled oscillation circuit in one mobile communication device.

[0004]

In the case where a plurality of oscillators are provided in one communication device as in the former case, the entire communication device naturally becomes large and the cost becomes high.

[0005] In the latter case, although the former problem can be solved, its practicality is very low in practice. For example, a plurality of communication systems in the same area are naturally set to have completely different carrier frequencies. Moreover, these carrier frequencies have greatly different frequency bands, such as the MHz band and the GHz band.

It is practically impossible to operate such oscillation output signals having greatly different frequency bands stably by one voltage-controlled oscillation circuit.

Accordingly, in general, two oscillation circuits, that is, a voltage-controlled oscillation circuit for deriving an oscillation frequency of MHz and a control circuit unit (PLL circuit unit) for the purpose of enlarging the size and cost are generally considered. And a voltage-controlled oscillation circuit for deriving an oscillation frequency of GHz and a control circuit unit (PLL circuit unit).

The present invention has been devised in view of the above-described problems, and has as its object the purpose of providing a single control circuit unit even if the oscillation frequencies F ₁ and F _{2 of} two oscillation output signals are significantly different. To provide a voltage-controlled high-frequency oscillation circuit capable of obtaining a stable oscillation output signal.

[0009]

According to a first aspect of the present invention, there is provided an oscillation circuit section including a resonance circuit section to which a control voltage for controlling an oscillation frequency is supplied and operating at a predetermined resonance frequency by the voltage; A frequency multiplying circuit for frequency multiplying a fundamental oscillation signal of a predetermined frequency output from the filter, a filter circuit for extracting only a predetermined multiplied frequency component from an output signal of the frequency multiplying circuit, and the oscillating circuit A voltage control circuit unit that adjusts the control voltage based on the frequency of the fundamental oscillation signal of the above.A fundamental oscillation signal of the oscillation circuit unit and a signal obtained by frequency-doubling the fundamental oscillation signal are output to the outside as oscillation output signals. A voltage controlled type high frequency oscillation circuit characterized by outputting.

According to a second aspect of the present invention, there is provided an oscillation circuit including a resonance circuit section to which a control voltage for controlling an oscillation frequency and a switching voltage for switching the oscillation frequency to a different frequency band are applied, and which operates at a predetermined resonance frequency with both voltages. Unit, a frequency multiplier circuit for frequency-multiplying a fundamental oscillation signal of a predetermined frequency output from the oscillator circuit unit, and a filter circuit for extracting only a predetermined frequency component from the output signal of the frequency multiplier circuit unit And a voltage control circuit unit that adjusts the control voltage based on the frequency of a basic oscillation signal of the oscillation circuit unit, and oscillates an output signal of the oscillation circuit unit and a signal obtained by multiplying the output signal. This is a voltage-controlled high-frequency circuit that is output as a signal to the outside.

[0011]

As described above, according to the present invention, the fundamental oscillation signal output from the oscillation circuit section is directly derived to the outside as the first oscillation output signal, and this fundamental oscillation signal is output to the frequency multiplication circuit section. For example, the frequency is doubled, only the frequency components corresponding to the frequency after the frequency multiplication are extracted, and the multiplied signal is derived to the outside as a second oscillation output signal.

Accordingly, two oscillation output signals having different oscillation frequency bands, for example, an oscillation output signal of about 900 MHz and an oscillation output signal of about 1.8 GHz are obtained.

Further, when a continuous change or a minute change in the oscillation output signal is required, the control voltage is adjusted.
In the present invention, whether the oscillation output signal is about 900 MHz or about 1.8 GHz, the fundamental oscillation signal output from the oscillation circuit unit is detected, and the frequency of the fundamental oscillation signal is detected. Adjusted properly. That is, regardless of the oscillation frequencies of the two oscillation output signals, the control is performed based on the original signal (basic oscillation signal) of the oscillation circuit section.
One voltage control circuit unit that can detect a specific frequency band can handle this.

Thus, a voltage-controlled high-frequency oscillation circuit in which a stable oscillation output signal can be obtained with a single control circuit section is provided, and an oscillator incorporating the same and a PLL circuit section as a voltage control circuit section connected thereto are simplified. And miniaturization.

In the second aspect of the invention, the switching voltage for discretely controlling the oscillation frequency is supplied to the resonance circuit to shift up and down the resonance frequency of the resonance circuit. In addition to the above-described functions and effects, it is easy to control the oscillation frequency discretely. For example, the first oscillation output signal and the second oscillation output signal
The frequency relationship with the oscillation output signal is not limited to the multiplication relationship, and an oscillation frequency suitable for practical use can be easily selected.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A voltage-controlled high-frequency oscillation circuit according to the present invention will be described below with reference to the drawings.

FIG. 1 is an overall block circuit diagram corresponding to the first invention, and FIG. 2 is a circuit diagram showing a high-frequency oscillation circuit section in FIG.

The voltage controlled high-frequency oscillation circuit according to the present invention includes an oscillation circuit section A including a resonance circuit section A ₁ , a negative resistance circuit section A ₂ and an amplification circuit section A ₃ , a frequency multiplication circuit section B, and a filter circuit. It comprises an oscillating section constituted by a section C, and a voltage control circuit section D for controlling a control voltage of the oscillating circuit section A.

Resonant circuit section A constituting oscillation circuit section A
Numeral ₁ is constituted by connecting a variable capacitance element to a resonance element, a microstrip line, or a strip line and a fixed capacitance element, and equivalently constitutes an LC resonance circuit. The resonance circuit portion A _1, control voltage Vt for controlling L-C resonant circuit of the resonance frequency (oscillation frequency) continuously or micro
Is supplied to the control voltage terminal VT.

The resonance circuit section A ₁ resonates at a predetermined resonance frequency according to the control voltage Vt. Actually, as shown in FIG. 2, the LC resonance circuit mainly includes the strip line S
L _2, capacitors C _4, is composed of a varicap diode CV, depending on the oscillation frequency as a reference, the length of the strip line SL, the varicap diode CV, combined capacitance of the capacitor C ₄ is set. By supplying the control voltage Vt of a predetermined voltage to the resonant circuit A _1, a capacitance component of the varicap diode CV, i.e., L
The capacitance component of the −C resonance circuit changes, and the resonance frequency can be controlled continuously or minutely in the variable capacitance range of the varicap diode.

The negative resistance circuit section A ₂ is mainly composed of a transistor or the like, and determines an oscillation condition for stably oscillating the signal of the resonance circuit section A ₁ . Amplifying circuit unit A ₃ is mainly made of transistors, which transistors cooperates negative resistance circuit part B, and derives the fundamental oscillation signal x having a predetermined frequency.

Actually, as shown in FIG. 2, the negative resistance circuit section A ₂ includes an amplifying circuit section A ₃ centering on the transistor Q _2.
Is composed mainly of the transistor Q ₁ and the transistor Q _1
The fundamental oscillation signal x is derived from the output portion (collector) of _{1 as} the output of the oscillation circuit section A. Incidentally, a bias power supply terminal Vcc to the amplifier circuit portion A _3.

The basic oscillation signal x of the oscillation circuit section A is directly output to the outside from the output terminal OUT ₁ as a _first oscillation output signal y ₁ , and is simultaneously output to the frequency multiplication circuit section B.

[0024] In Figure 2, the basic oscillation signal x first through filter circuit composed of a coil L ₄ capacitors C ₁₁ -C ₁₂
Is derived from the oscillation output terminal OUT _1. Further, the input signal of the transistor Q ₄ constituting a frequency multiplier circuit section B.

The frequency multiplying circuit section B mainly comprises a transistor and a reactance element, and performs a multiplying process on the fundamental oscillation signal x (frequency f) of the oscillation circuit section A.

The filter circuit section C includes a capacitor,
Frequency multiplication circuit section B consisting of an inductance element and the like
Is configured to obtain a predetermined frequency pass characteristic of extracting and passing only the frequency component multiplied by.

[0027] For example, frequency multiplier circuit section B, by changing the bias point of the transistor Q _4, 2 times the harmonic component of the input signal (fundamental oscillation signal x),
The output level of triple harmonic components,... Can be improved. The coil L ₅ ~L _6, the capacitor C ₁₆
What is necessary is just to make the pass band characteristic of the filter circuit section C composed of _.about.C2O correspond to the multiplied frequency component.

As a result, the filter circuit section C sets a signal having only a predetermined frequency component in the frequency-multiplied output signal of the basic oscillation signal x as a second oscillation output signal y ₂ .
The second is derived from the oscillation output terminal OUT _2.

The high-frequency oscillating section including the oscillating circuit section A, the frequency multiplying circuit section B, and the filter circuit section C includes:
The voltage control circuit section D is connected, and the oscillation output signals y ₁ , y
The oscillation frequency of ₂ is controlled.

The voltage control circuit section D is a PLL circuit section, and mainly includes the PLL-ICD ₁ and the L.L. P. F (low-pass filter) D ₂ , and further includes a temperature-compensated crystal oscillator and the like.

The voltage control circuit section D generates an oscillation output signal y
When some variation occurs in the oscillation frequency of _1, y ₂ is
A control voltage Vt that corrects this variation is created and supplied to the control voltage terminal VT of the oscillation circuit unit A. In this case, the control voltage Vt changes the oscillation frequency continuously. Further, in the communication system, it is necessary to change the oscillation frequency at minute intervals for each selected channel. At this time, the control voltage Vt is formed so that the oscillation output signals y ₁ and y ₂ have a predetermined oscillation frequency according to the channel, and the control voltage Vt is supplied to the control voltage terminal VT. In this case, the control voltage Vt slightly changes the oscillation frequency.

In the present invention, the monitoring of the oscillation frequency of the oscillation output signals y ₁ and y ₂ performed by the voltage control circuit D is performed based on the frequency of the basic oscillation signal x of the oscillation circuit A. Even if the second oscillation output signal y ₂ has been subjected to the multiplication process,
This is performed based on the basic oscillation signal x before the frequency multiplication circuit section B performs the multiplication process.

In the PLL-ICD ₁ , for example,
Desired frequency of the set fundamental oscillation signal (reference frequency)
And the frequency of the fundamental oscillation signal x actually output is compared, and the signal of the phase difference is referred to as L.F. P. In FD _2, is changed to DC current becomes a control voltage Vt.

[0034] With the above configuration, the oscillation circuit unit A outputs the fundamental oscillation signal x of the frequency f ₁ based on the control voltage Vt. Then, the oscillation frequency F from the first output terminal OUT _{1
A first} oscillation output signal y ₁ of ₁ (= f ₁ ) is derived. At the same time, the fundamental oscillation signal x having the frequency f ₁ is subjected to a predetermined multiplication process by the frequency multiplication circuit B, and the multiplied frequency F ₂ (F ₂ = k ·
the second oscillating output signal y ₂ in f _1), second output terminals O
Output from UT ₂ .

That is, two oscillation output signals having completely different frequency bands can be output by the same voltage controlled oscillation circuit.

Further, even if the oscillation output signals y ₁ and y ₂ have completely different frequency bands, the signals monitored by the voltage control circuit D are the same as the fundamental oscillation signals x whose frequencies are close to each other. Voltage control circuit section D, ie, a single control system, greatly simplifies the circuit configuration of the voltage-controlled high-frequency oscillation circuit, and greatly contributes to downsizing of oscillators and communication devices equipped with this circuit. it can.

Next, the actual application of the voltage controlled high frequency oscillation circuit of the present invention will be described. For example, the voltage controlled high frequency oscillation circuit is used as a first intermediate frequency local oscillation circuit of a receiving circuit in a mobile communication device. The required frequency of the oscillation output signal is actually slightly different from the carrier frequency, but here, the description will be made assuming that the frequency of the oscillation output signal and the actual carrier frequency are the same.

For example, in the GSM system (communication system for mobile phones in Europe), a carrier frequency of about 900 MHz band is used. In the DECT system (home cordless telephone system in the UK), a carrier frequency of about 1.8 GHz is used. As a control voltage type high frequency oscillation circuit that can support both such communication systems,
In certain control voltage Vt, the frequency f from the oscillator circuit unit A, for example, a 900MHz fundamental oscillation signal x sets the resonance circuit portion A ₁ to derive. At the same time, the frequency multiplication circuit section B is multiplied by 2 and the filter circuit section C
Is set around 1.8 GHz.

Thus, at a constant control voltage Vt, the oscillation circuit section A outputs a basic oscillation signal x having a frequency f = 900 MHz.
Is derived. That is, an oscillation output signal y ₁ having an oscillation frequency F ₁ = 900 MHz is obtained from the first output terminal OUT ₁ .

At the same time, the fundamental oscillation signal x output from the oscillation circuit section A is subjected to double frequency multiplication processing in the frequency multiplication circuit section B, and is passed through the filter circuit section C to the second oscillation output terminal. second oscillation output signal y ₂ is derived for the frequency F ₂ = 1.8GHz from OUT _2.

In this way, the GSM system and the DEC
A voltage-controlled high-frequency oscillation circuit compatible with the T method is obtained.

Here, due to the influence of a load or the like, the oscillation frequency F ₁ of the oscillation output signals y ₁ and y ₂ is actually 900.
MHz and F ₂ = 1.8 GHz may slightly fluctuate. At this time, the control voltage Vt for correcting the fluctuation is supplied by the voltage control circuit D. Further, the communication of the GSM system, for example, channel every several tens kHz is set, even in the case of obtaining the oscillation frequency F ₂ corresponding to the channel, the above-mentioned voltage control circuit section D
Thereby, a control voltage Vt for controlling the oscillation frequency corresponding to the channel to be selected is supplied.

FIG. 3 is a block circuit diagram of a voltage-controlled high-frequency oscillator circuit according to a second embodiment of the present invention.

In this embodiment, in particular, the resonance circuit section A ₁
Switching means A ₁₁ operated by the switching voltage VS and the switching voltage Vs switching voltage Vs for switching the oscillation frequency discretely is supplied is connected.

The switching means A ₁₁ includes a resonance circuit section A ₁₀
And has a diode Di and a resistor R as switching means for changing the inductance component and / or the capacitance component of the LC resonance circuit. The capacitor Cs and the inductance element Ls are connected.

[0046] Figures 4-7 show the switch means A _11, including a resonant circuit.

Thus, when the switching voltage Vs is supplied, the diode Di is turned on, and the resonance frequency is shifted up or down by changing the inductance component or the capacitance component of the LC resonance circuit. I do. 4 and 5 show examples of upshifting, and FIGS. 6 and 7 show downshifting.

[0048] For example, in FIG. 4, when the switching means A ₁₁ is predetermined switching voltage Vs is supplied, the diode Di becomes ON state, the line length of the strip line L ₂ is substantially shortened. As a result, the resonance frequency becomes higher.

With such a circuit, the resonance circuit section A ₁
Can be discretely switched.

[0050] This is, for example, the first oscillation frequencies F ₁ of the oscillation output signal y ₁ and (f ₁₎ and the oscillation frequency F ₂ of the second oscillating output signal y ₂ is required, not a relationship of multiplication of In such a case, it becomes easy to respond.

For example, the AMPS system (U.S. mobile communication system: carrier frequency 880 MHz) and the PCS system (U.S. mobile communication system: carrier frequency 1.
An example is a dual mode control voltage type high frequency oscillation circuit corresponding to 9 GHz.

For example, the switching voltage vs. the switching means
_{When a} voltage that does not operate the circuit ₁₁ is supplied, the oscillation circuit unit A outputs a fundamental oscillation signal x having a frequency f ₁ of 880 MHz. In this case, the first output terminal OUT ₁ derived directly from the oscillator circuit unit A, as the oscillation frequencies F ₁ oscillating output signal y ₁ of 880MHz is derived.

The switching voltage vs. the switching means A
If a voltage for operating the _11, the frequency f ₂ of the fundamental oscillation signal x outputted from the oscillation circuit unit A is 950 MHz. In this case, the fundamental oscillation signal x, is for example, doubled frequency multiplier unit B, and is a square waveform by the filter circuit station C, a oscillation output signal y ₂ of 1.9GHz is derived from the second output terminal OUT ₂ You. Note that the first output terminal OUT
_When the oscillation output signal y ₁ of ₁ to 880 MHz is derived, 1.76 G is output from the second oscillation output terminal OUT ₂ .
Hz oscillation output signal y ₂ are led in, but ignore it. In addition, the second oscillation output terminal OUT ₂ outputs 1.9.
When the oscillation output signal y ₂ in GHz is derived is oscillation output signal y ₁ of the first 950MHz from the oscillation output terminal OUT ₁ is derived, it may be ignored.

Also in this case, since the frequency of the fundamental oscillation signal x of the oscillation circuit section A is relatively close to 880 MHz and 950 MHz, the voltage control circuit section D makes it easy to correct the oscillation frequency fluctuation. be able to.

In particular, since the control of the discrete oscillation frequency is substantially performed by the switching voltage Vs and the switching means ₁₁ , the change of the control voltage Vt is very small, and the configuration of the voltage control circuit section D is further improved. Can be easy. That is, the control voltage Vt only operates to compensate for the fluctuation of the basic oscillation signal x output from the oscillation circuit unit A.

In each of the above-described embodiments, the first oscillation output signal is derived from the first oscillation output terminal OUT ₁ and the second oscillation output signal is derived from the second oscillation output terminal OUT _2. Alternatively, the frequency multiplication circuit sections may be connected in multiple stages, and the third oscillation output signal and the fourth oscillation output signal may be derived from the sections through the filter section. Further, frequency multiplication circuits having different multiplication factors may be arranged in parallel, and the third oscillation output signal and the fourth oscillation output signal may be derived through the filter unit.

[0057]

According to the present invention, in a voltage-controlled high-frequency oscillation circuit for obtaining oscillation output signals of at least two oscillation frequencies F ₁ and F ₂ , the two oscillation frequencies F ₁ and F ₂
The voltage control circuit unit that controls the control voltage detects the fluctuation in the frequency of the fundamental oscillation signal that is the output of the oscillation circuit unit and supplies the appropriate control voltage to the resonance circuit unit even if the bandwidths of the oscillation circuit units are different. . That is, even if the oscillation circuit derives oscillation output signals having different oscillation frequencies, the voltage control circuit section can be controlled by one system. Thus, the entire circuit configuration can be simplified, and a small-sized and low-cost voltage-controlled high-frequency oscillation circuit can be obtained.

As a result, a voltage-controlled high-frequency oscillation circuit for obtaining an oscillation output signal with a very stable oscillation frequency is obtained.

Further, by selectively switching the frequency by using a switching voltage and a switching means for controlling the oscillation frequencies in different frequency bands, the oscillation frequencies of the plurality of oscillation output signals can be diversified, and A high-voltage-controlled high-frequency oscillation circuit is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a voltage controlled high frequency oscillation circuit according to a first invention.

FIG. 2 is a circuit diagram of an oscillation circuit unit used in a voltage-controlled high-frequency oscillation circuit.

FIG. 3 is a block diagram of a voltage-controlled high-frequency oscillation circuit according to a second invention.

FIG. 4 is a circuit diagram of a resonance circuit portion provided with a switching means used in the second invention.

FIG. 5 is another circuit diagram of a resonance circuit portion provided with a switching means used in the second invention.

FIG. 6 is another circuit diagram of a resonance circuit portion provided with a switching means used in the second invention.

FIG. 7 is another circuit diagram of a resonance circuit portion provided with a switching means used in the second invention.

[Explanation of Symbols] A ₁ ··· resonance circuit section A ₁₁ ··· switch means A ₂ ··· negative resistance circuit section A ₃ ··· amplification circuit section B ··· frequency multiplication circuit section C · ... Filter circuit section D ... Control voltage control circuit section

Claims (2)

[Claims] 1. An oscillation circuit section including a resonance circuit section supplied with a control voltage for controlling an oscillation frequency and operating at a predetermined resonance frequency by the voltage, and a basic oscillation signal of a predetermined frequency output from the oscillation circuit section. A frequency multiplying circuit unit for multiplying the frequency, a filter circuit unit for extracting only a predetermined multiplied frequency component from an output signal of the frequency multiplying circuit unit, and a frequency of a fundamental oscillation signal of the oscillation circuit unit. A voltage control circuit unit for adjusting the control voltage, wherein a fundamental oscillation signal of the oscillation circuit unit and a signal obtained by frequency-multiplying the fundamental oscillation signal are output to the outside as an oscillation output signal. High frequency oscillation circuit. 2. An oscillation circuit unit including a resonance circuit unit to which a control voltage for controlling an oscillation frequency and a switching voltage for switching the oscillation frequency to a different frequency band are applied, and the voltage is used to operate at a predetermined resonance frequency. A frequency multiplying circuit for frequency multiplying a basic oscillation signal of a predetermined frequency output from the oscillation circuit; a filter circuit for extracting only a predetermined multiplied frequency component from an output signal of the frequency multiplying circuit; A voltage control circuit unit that adjusts the control voltage based on the frequency of the basic oscillation signal of the oscillation circuit unit. The output signal of the oscillation circuit unit and a signal obtained by multiplying the output signal are externally output as an oscillation output signal. A voltage controlled high frequency circuit characterized by outputting.