CN1086063C - Voltage controlled oscillator - Google Patents
Voltage controlled oscillator Download PDFInfo
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- CN1086063C CN1086063C CN97104590A CN97104590A CN1086063C CN 1086063 C CN1086063 C CN 1086063C CN 97104590 A CN97104590 A CN 97104590A CN 97104590 A CN97104590 A CN 97104590A CN 1086063 C CN1086063 C CN 1086063C
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- voltage controlled
- coupled
- controlled oscillator
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Abstract
The present invention provides a voltage controlled oscillator comprises a first branch having at least an inductance in series with a first pair of series structure voltage controlled capacitance, each voltage controlled capacitance has an electrode coupling to a first public node, the first public node connects with a DC input terminal; a second branch in parallel connection with the first branch, which has a second pair of series structure voltage controlled capacitance, each voltage controlled capacitance has an electrode coupling to a second public node, the second public node connects with a DC input terminal; an amplifier having an input terminal coupling with the first and the second branches, and having a output terminal supplying load; a feedback circuit coupling the amplifier to the first public node and supplying positive feed back to the input terminal of the amplifier.
Description
The present invention relates to comprise the voltage controlled oscillator of a resonant circuit in parallel.The present invention specifically is used for, but need not to be limited to, and improves the bandwidth characteristic of conventional Hartley (Hartley) structure voltage controlled oscillator.
The bandwidth of prior art voltage controlled oscillator may be inadequate for some application.For example, in United States Patent (USP) 4450416, described a wideband voltage controlled oscillator, it has a resonant circuit that comprises a plurality of variable capacitance diodes, an inductance and electric capacity.Control voltage adds to the negative electrode of a plurality of variable capacitance diodes to change their electric capacity.Accordingly, the frequency of voltage controlled oscillator can be controlled by changing control voltage.Regrettably, this oscillator requires the very little capacitance (this value is generally the 2-5 pico farad) in resonant circuit, has therefore limited the improvement of bandwidth.
Disclose open-loop gain compensating wide band Colpitts (Colpitts) voltage controlled oscillator in the United States Patent (USP) 5144264, it has the direct current loss more level and smooth than the Colpitts voltage controlled oscillator of other prior art.Yet the bandwidth of this wideband voltage controlled oscillator is not all abundant to all application.
The wideer bandwidth range of Hartley wideband voltage controlled oscillator through being usually used in obtaining to reach than available Colpitts voltage controlled oscillator.Regrettably, conventional Hartley wideband voltage controlled oscillator shortcoming is: the direct current loss descends with frequency.The decline of this direct current loss can influence phase noise performance, and this is unfavorable to some application.
The objective of the invention is to overcome or alleviate in the problem relevant at least one with voltage controlled oscillator.
According to an aspect of the present invention, provide a voltage controlled oscillator, comprising:
First branch road comprises the inductance that at least one is connected with first pair of cascaded structure voltage controlled capacitor, and each voltage controlled capacitor has an electrode that is coupled to a common node, and common node links to each other with a direct current input;
Second branch road, in parallel with described first branch road, described second branch road comprises second pair of cascaded structure voltage controlled capacitor, and each voltage controlled capacitor has an electrode that is coupled to a common node, and described common node links to each other with described direct-flow input end;
One amplifier has an input that is coupled to described first branch road and described second branch road, and described amplifier has an output that is used to provide load;
One feedback device, the described amplifier that is coupled is to described first common node, and wherein said feedback device is suitable for providing positive feedback to the described input of described amplifier.
Preferably, described at least one inductance can comprise two inductance, and they are coupled to the electrode separately of described a pair of voltage controlled capacitor.
Adapt, described first pair of cascaded structure voltage controlled capacitor is a pair of variable capacitance diode, and they have the negative electrode that directly intercouples.
Preferably, described two inductance can be coupled to the anode separately of described a pair of variable capacitance diode.
Adapt, the also a pair of variable capacitance diode of described second pair of cascaded structure voltage controlled capacitor, they have the negative electrode that directly intercouples.
Preferably, the described a pair of variable capacitance diode of described first branch road can be in the monolithic encapsulation.The described a pair of variable capacitance diode of described second branch road also can be in the monolithic encapsulation.
Preferably, described first common node can be coupled to described direct-flow input end by a choke.Described second common node also can be coupled to described direct-flow input end by another choke.
Adapt, described second common node can be coupled to described feedback device.
For making easy to understand of the present invention and enforcement, the preferred embodiment shown in the accompanying drawing is described now, wherein:
Fig. 1 is the schematic diagram according to voltage controlled oscillator of the present invention;
Fig. 2 illustrates conventional series L-C circuit;
Fig. 3 illustrates the curve chart of the impedance Z characteristic of Fig. 2 circuit with frequency change;
Fig. 4 illustrates an inductance and variable capacitance diode series circuit.
With reference to figure 1, it illustrates voltage controlled oscillator 1, and it comprises first branch road 2 and second branch road 3 in parallel.First branch road 2 comprises pair of series structure voltage controlled capacitor, and form is a variable capacitance diode 4,5, and each variable capacitance diode all has the negative electrode that is coupled to the first common node Cn1 6,7 separately.The first common node Cn1 is coupled to direct-current control voltage input Vctrl by a high frequency choke coil L1.First branch road 2 also comprises two inductance 9 and 11, and they are coupled to the anode separately 8,10 of variable capacitance diode 4,5.The other end of inductance 11 is coupled to earth potential 12, and the other end of inductance 9 is coupled to second branch road 3 by coupling capacitance C1.
The electrode that is connected to anode 17 of capacitor C 1 is coupled to earth potential 12 by a high frequency choke coil L3.And the electrode that is connected of capacitor C 1 and C2 and an end of inductance 9 are coupled to earth potential 12 by high frequency choke coil L6.Further, emitter E is coupled to earth potential 12 by resistance R 3 and high frequency choke coil L4.
The electrode that is connected of capacitor C 3 and C4 is coupled to earth potential 12 by resistance R 1, and collector electrode C is coupled to dc power supply terminal VCC by high frequency choke coil L5.Further, comprise that the dividing potential drop net of two series resistance R4, R5 is connected between feeder ear VCC and the earth potential 12, wherein, the common node of R4 and R5 is coupled to base stage B suitable biasing is provided.
In this preferred embodiment, variable capacitance diode the 4, the 5th is included in the back-to-back variable capacitance diode of direct coupling in the monolithic encapsulation 20.Similarly, variable capacitance diode the 13, the 14th is included in the back-to-back variable capacitance diode of direct coupling in the monolithic encapsulation 21.
In the use, for excitation voltage controlled oscillator 1 enters oscillatory regime, a direct current voltage adds to VCC (such as 12V).Another can add to control voltage input terminal Vctrl from a phase-locked loop (not shown) by the direct voltage between 1V to 13V.
The background noise or the white noise that appear at base stage B are enough to encourage voltage controlled oscillator 1 usually.The sub-fraction of noise that appears at the amplification of collector electrode C feeds back to base stage B by a positive feedback path.This positive feedback be since between base stage B and collector electrode C first 180 the degree phase shift.The phase shift of second 180 degree occurs in the feedback network of the wattless component that includes in resistance R 1, the branch road 2 and 3 and capacitor C 1 and C2.Therefore, total amount having taken place is the phase shift of 360 degree.The signal amplitude that arrives base stage B is continued to be amplified, until the amplitude of the non-linear restricting signal of active loss and transistor T R.Further, maximum because the resonance frequency fo that is amplified in the wattless component in branch road 2 and 3 of signal goes up, voltage controlled oscillator 1 vibrates on this resonance frequency fo.
To understand the present invention in order further helping, to describe Fig. 2 and Fig. 3 now.Figure 2 illustrates series L-C circuit, it has the impedance Z characteristic with frequency change.As shown in Figure 3, the impedance Z characteristic is in resonance frequency fo minimum.When being lower than fo, along with the increase of frequency, the electric capacity of L-C circuit increases.On the contrary, when being higher than fo, along with the increase of frequency, the L-C circuit inductance increases.
As can be seen, the equivalent inductance Leq of series L-C circuit can be calculated by following formula:
Leq=L[1-(2 π fo/2 π f)]
2For all f＞fo wherein, resonance frequency
Suppose that capacitor C replaced by variable capacitance diode Cv now, and a DC control voltage Vctrl adds to the negative electrode of variable capacitance diode Cv by a high frequency choke coil Lc.This will form L-Cv circuit shown in Figure 4.Add to the direct-current control voltage Vctrl of the L-Cv circuit of Fig. 4 by increase, the electric capacity of variable capacitance diode Cv will reduce.Accordingly, by increasing control voltage Vctrl gradually, the resonance frequency fo of L-Cv circuit will increase gradually.
Refer again to Fig. 1, when being added with control voltage Vctrl, the electric capacity of variable capacitance diode 4,5 reduces.Accordingly, the impedance Z of first branch road 2 is mainly perception, and comprises the first equivalent inductance Leq1 and the second equivalent inductance Leq2.First equivalent inductance comprises variable capacitance diode 4 and inductance 9, and the second equivalent inductance Leq2 comprises variable capacitance diode 5 and inductance 11.Yet, though control voltage Vctrl also adds to variable capacitance diode 13 and 14, the second branch roads 3 keep capacitive.
How table 1 shows the first and second equivalent inductance Leq1 of voltage controlled oscillator 1 and Leq2 with frequency change.As shown, suppose f＞fo always, equivalent inductance Leq1 and Leq2 are along with the frequency that is provided reduces.As a result, the bandwidth of oscillator 1 will be by useful increase.
Table 1
| Vctrl (volt) | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| The electric capacity of variable capacitance diode 4 (pico farad) | 23.075 | 20.581 | 18.439 | 16.591 | 14.983 | 13.572 | 12.319 | 11.196 | 10.180 |
| The inductance of inductance 9 (nanohenry) | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 | 18 |
| Resonance frequency fo (MHz) | 246.95 | 261.49 | 276.26 | 291.24 | 306.47 | 322.01 | 337.98 | 354.53 | 371.80 |
| Operating frequency (MHz) | 372.4 | 392.3 | 412.2 | 432.1 | 452 | 472 | 492.2 | 513.1 | 534.7 |
| The equivalent inductance Leq1 of variable capacitance diode 4 and inductance 9 (nanohenry) | 10.084 | 10.003 | 9.915 | 9.823 | 9.725 | 9.622 | 9.513 | 9.407 | 9.297 |
| The electric capacity of variable capacitance diode 5 (pico farad) | 23.075 | 20.581 | 18.439 | 16.590 | 14.983 | 13.572 | 12.319 | 11.196 | 10.180 |
| The inductance of inductance 11 (nanohenry) | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 |
| Resonance frequency fo (MHz) | 331.32 | 350.82 | 370.64 | 390.74 | 411.17 | 432.02 | 453.45 | 475.65 | 498.83 |
| Operating frequency (MHz) | 372.4 | 392.3 | 412.2 | 432.1 | 452 | 472 | 492.2 | 513.1 | 534.7 |
| The equivalent inductance Leq2 of | 2.084 | 2.003 | 1.915 | 1.823 | 1.725 | 1.622 | 1.513 | 1.407 | 1.297 |
| Leq1/Leq2 | 4.8379 | 4.9945 | 5.1776 | 5.3891 | 5.6377 | 5.9314 | 6.2889 | 6.6879 | 7.1692 |
| Leq1/(Leq1+Leq2) | 0.8287 | 0.8332 | 0.8381 | 0.8435 | 0.8493 | 0.8557 | 0.8628 | 0.8699 | 0.8776 |
And the ratio Leq1/Leq2 of first and second equivalent inductances increases with frequency, and therefore, feedback ratio directly depends on ratio Leq1/Leq2.Accordingly, feedback ratio will increase with frequency, the generation that this is useful the one level and smooth direct current loss that obtains for wide bandwidth.
Though the present invention describes with reference to preferred embodiment, should be appreciated that the present invention is not limited by embodiment described herein.
Claims (8)
1, a voltage controlled oscillator comprises:
First branch road comprises the inductance that at least one is connected with first pair of cascaded structure voltage controlled capacitor, and each described voltage controlled capacitor has an electrode that is coupled to first common node, and described common node links to each other with a direct current input;
Second branch road, in parallel with described first branch road, described second branch road comprises second pair of cascaded structure voltage controlled capacitor, and each described voltage controlled capacitor has an electrode that is coupled to second common node, and described second common node links to each other with described direct-flow input end;
One amplifier has one and is coupled to described first branch road and the described second branch road input, and described amplifier has an output that is used to provide load;
A feedback device that comprises resistance and capacitance network, the described amplifier that is coupled is wherein stated feedback device and is suitable for providing positive feedback to the described input of described amplifier to described first common node.
2, voltage controlled oscillator as claimed in claim 1, wherein said at least one inductance comprises two inductance, they are coupled to the electrode separately of described a pair of voltage controlled capacitor.
3, voltage controlled oscillator as claimed in claim 2, wherein said first pair of cascaded structure voltage controlled capacitor is a pair of variable capacitance diode, they have the negative electrode that directly intercouples.
4, voltage controlled oscillator as claimed in claim 3, wherein said two anodes separately that are inductively coupled to described a pair of variable capacitance diode.
5, voltage controlled oscillator as claimed in claim 4, wherein said second pair of cascaded structure voltage controlled capacitor is a pair of variable capacitance diode, they have the negative electrode that directly intercouples.
6, voltage controlled oscillator as claimed in claim 1, wherein said first common node is coupled to described direct-flow input end by a choke.
7, voltage controlled oscillator as claimed in claim 6, wherein said second common node is coupled to described direct-flow input end by another choke.
8, voltage controlled oscillator as claimed in claim 7, wherein said second common node is coupled to described feedback device.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MYPI9601226 MY115728A (en) | 1996-04-03 | 1996-04-03 | Voltage controlled oscillator |
| MYPI9601226 | 1996-04-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1168024A CN1168024A (en) | 1997-12-17 |
| CN1086063C true CN1086063C (en) | 2002-06-05 |
Family
ID=19749734
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97104590A Expired - Fee Related CN1086063C (en) | 1996-04-03 | 1997-04-02 | Voltage controlled oscillator |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN1086063C (en) |
| ID (1) | ID16411A (en) |
| MY (1) | MY115728A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106877819B (en) * | 2016-11-21 | 2020-08-11 | 成都仕芯半导体有限公司 | Voltage controlled oscillator based on composite resonator |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4847572A (en) * | 1986-10-30 | 1989-07-11 | Toko, Inc. | Electronic tuning circuit for AM receiver |
| US4851791A (en) * | 1987-09-29 | 1989-07-25 | Compagnie D'electronique Et De Piezoelectricite - C.E.P.E. | Temperature-compensated piezoelectric oscillator |
| EP0648009A1 (en) * | 1993-10-06 | 1995-04-12 | Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho | Oscillating circuit |
-
1996
- 1996-04-03 MY MYPI9601226 patent/MY115728A/en unknown
-
1997
- 1997-04-01 ID IDP971099A patent/ID16411A/en unknown
- 1997-04-02 CN CN97104590A patent/CN1086063C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4847572A (en) * | 1986-10-30 | 1989-07-11 | Toko, Inc. | Electronic tuning circuit for AM receiver |
| US4851791A (en) * | 1987-09-29 | 1989-07-25 | Compagnie D'electronique Et De Piezoelectricite - C.E.P.E. | Temperature-compensated piezoelectric oscillator |
| EP0648009A1 (en) * | 1993-10-06 | 1995-04-12 | Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho | Oscillating circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| ID16411A (en) | 1997-09-25 |
| CN1168024A (en) | 1997-12-17 |
| MY115728A (en) | 2003-08-30 |
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