WO2010059445A1 - Low noise oscillators - Google Patents
Low noise oscillators Download PDFInfo
- Publication number
- WO2010059445A1 WO2010059445A1 PCT/US2009/063666 US2009063666W WO2010059445A1 WO 2010059445 A1 WO2010059445 A1 WO 2010059445A1 US 2009063666 W US2009063666 W US 2009063666W WO 2010059445 A1 WO2010059445 A1 WO 2010059445A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- coupled
- transistor
- resistor
- voltage
- differential amplifier
- Prior art date
Links
- 239000003990 capacitor Substances 0.000 claims description 13
- 238000000034 method Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229910002601 GaN Inorganic materials 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/02—Details
- H03B5/04—Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
- H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
- H03B5/1203—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier being a single transistor
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
- H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
- H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
- H03B5/1231—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier comprising one or more bipolar transistors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B2200/00—Indexing scheme relating to details of oscillators covered by H03B
- H03B2200/006—Functional aspects of oscillators
- H03B2200/0088—Reduction of noise
Definitions
- the present invention relates to RF oscillators and more particularly to RF oscillators having low levels of phase noise.
- low noise oscillators have a wide range of applications such as in navigation, radars and communication systems.
- flicker noise from the transistors may significantly degrade oscillator phase noise.
- One technique used to produce low noise oscillators is to screen oscillator transistors for devices having low phase noise. This is time consuming, costly and can sometimes lead to unpredictable yields. Obtaining RF transistors with flicker noise much less than 1 kHz is desired, but is generally considered impractical. More particularly, RF oscillator phase noise is a dominant factor limiting the performance of many systems.
- a time based related attribute is the short-term stability or Allan variance. The basic mechanisms of phase noise generation in oscillators are well understood and described in the literature.
- phase noise is often described by its spectral properties.
- phase noise can have a 1/f 1 characteristic, with n being an integer.
- n generally varies from 0 to 3.
- D. B. Leeson in the paper entitled “A simple model of feedback oscillator noise spectrum,” Proc. IEEE, vol. 54, pp. 329-330, Feb. 1966, electronic noise within the resonator bandwidth is increased such that flicker noise is converted into 1/f phase noise when the device is embedded into a high Q oscillator circuit.
- the implication of this conversion is that noise within the resonator bandwidth is greatly increased.
- Obtaining lower phase noise then requires either lower 1/f phase noise transistors or higher Q resonators.
- the 1/f phase noise of a RF transistor relates to the phase noise at small offset frequencies from the center resonance frequency of the oscillation signal .
- the 1/f term applies to noise having a 1/f spectral shape when offset from the 1
- 1/f phase noise can be associated with the actual flicker noise of the transistor, but the specific mechanisms of conversion are also not well understood. Obtaining RF transistors having very low 1/f phase noise is quite difficult due to compromises between RF performance and flicker noise.
- the desire is to provide an RF oscillator with very low phase noise. In addition, it is desired to minimize RF power variations with temperature and process variations.
- an oscillator having: a transistor; a resonant circuit coupled between an output electrode of the transistor and a control electrode of the transistor; and a dc bias circuit for the transistor.
- the dc bias circuit comprises: a voltage producing circuit and a differential amplifier.
- the differential amplifier includes: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.
- the oscillator includes a voltage source having: one potential coupled to one terminal of the voltage producing circuit; and a second potential coupled to a second terminal of the voltage producing circuit; and wherein a third terminal of the voltage producing circuit is coupled to the second input of the differential amplifier.
- the voltage producing circuit includes a first resistor coupled between the first potential and the second input of the differential amplifier and a second resistor between an additional electrode of the transistor and the second potential.
- the oscillator includes an inductor coupled between the second input of the differential amplifier and the output electrode of the transistor.
- the oscillator includes a capacitor coupled between the first input of the differential amplifier and the output of the differential amplifier.
- the oscillator includes a third resistor and a fourth resistor connected to the third resistor at a node, such node being coupled to the second potential through a capacitor, the third resistor being coupled between the output of the differential amplifier and the node and the fourth resistor being coupled between the node and the control electrode of the transistor.
- the fixed voltage is a voltage produced by a resistor divider coupled between the first and second potentials.
- the SINGLE FIGURE is a schematic diagram of an RF oscillator according to the invention.
- the oscillator includes a transistor Ql; a resonant circuit 12 coupled between an output electrode, here collector electrode, of the transistor Ql and a control electrode, here base electrode, of the transistor Ql ; and a dc bias circuit 14 for the transistor Ql .
- the dc bias circuit 14 includes: a voltage producing circuit 16; and a differential amplifier 18.
- the differential amplifier 18 has: a first input (inverting (-) input) coupled to a fixed reference voltage; a second input (non- inverting (+)) coupled to the voltage producing circuit 16, such voltage producing circuit producing a voltage at the second input (non- inverting (+)) of the difference amplifier 18 related to current Ic passing through the output electrode
- a voltage source Vl has: one potential (+) coupled to one terminal of 22 the voltage producing circuit 14; and a second potential (-) coupled to a second terminal 24 of the voltage producing circuit 14.
- a third terminal 26 of the voltage producing circuit 14 is coupled to the second input (non-inverting (+)) of the differential amplifier 18.
- the voltage producing circuit 14 includes a first resistor R4 coupled between the first potential and the second input of the differential amplifier (non- inverting (+)) and a second resistor R5 between an additional electrode (emitter) of the transistor Ql and the second potential (i.e., terminal 24).
- An inductor Ll is coupled between the second input (non-inverting (+)) of the differential amplifierl ⁇ and the output electrode (collector) of the transistor Ql .
- a capacitor C3 is coupled between the first input (inverting (-)) of the differential amplifier 18 and the output 20 of the differential amplifier 18.
- a third resistor R3 and a fourth resistor R6 are connected together at a node 30, such node 30 being coupled to the second potential (i.e., terminal 24) through a capacitor C4, the third resistor R3 being coupled between the output 20 of the differential amplifier 18 and the node 30 and the fourth resistor R6 being coupled between the node 30 and the control electrode (base electrode) of the transistor Ql .
- the fixed voltage is a voltage produced at node 32 by a resistor divider 34 made up of resisters Rl and R2 coupled between the first and second potentials of the supply Vl . More particularly, the transistor Ql is the oscillator transistor.
- the differential amplifier 18 is chosen to have low flicker noise properties.
- a resistor R7 is the RF load resistor with typical value of 50 ohms.
- Inductor Ll is used for RF isolation and may also take the form of a distributed transmission line.
- Capacitor Cl is a bypass capacitor having very low reactance at the oscillation frequency.
- the two port device is the resonant feedback circuit 12 and could be a lumped element LC, an acoustic resonator such as SAW, or a distributed resonator such as a transmission line or a dielectric resonator.
- the two-port could include a means of tuning the oscillator frequency such as a varactor diode.
- Transistor Ql is shown as a bipolar device, but may also be a FET; in which case the control electrode is the gate electrode.
- the semiconductor material may be silicon, GaAs, GaN or other semiconductor materials.
- Biasing is provided by using as the differential amplifier 18 a differential amplifier having low flicker noise.
- a differential amplifier having low flicker noise For example, commercially available differential amplifiers are available with a typical flicker noise intercept of less than 10 Hz.
- a reference voltage formed by the voltage divider of Rl and R2 and also having low flicker noise is used as the inverting input, and a voltage proportional to collector current of the RF transistor is used as the non-inverting input.
- the feedback path from the voltage at the R4-L1 node is applied to the positive differential amp input due to the 180 phase shift of transistor Ql at low frequencies.
- the amplifier 19 positive input (non- inverting input (+)) becomes a negative feedback path, and the reference voltage at node 32 is applied to what is commonly used as the negative input to the op-amp.
- the output 20 from the differential amplifier 18 is used to provide a voltage for biasing the input (here emitter) to the RF transistor Ql .
- Resistor R3, R6 and capacitor C4 serve to isolate the RF signal from the biasing function.
- An additional capacitor C3 serves as a phase shift component to establish adequate phase margin and ensure that noise processes are not regenerated by the very high differential voltage gain.
- the biasing configuration ensures that the voltage of the non-inverting input (+) of the differential amplifier 18 will be essentially equal to the voltage of the inverting input (-).
- the noise at the inverting input (-) is derived from a reference voltage at node 32 with very low noise, the noise at the non-inverting input (+) will also be similarly quiet. Any noise in the collector current Ic of the RF transistor Ql will now be sensed by the biasing circuit 14 and the voltage present at the base of the RF transistor Ql will be adjusted to compensate for that noise. Noise which is normally present at the collector of the RF transistor Ql will essentially be translated back to the base of said transistor Ql. However, since the transistor Ql has a voltage gain from the collector to base electrode, voltage noise will similarly be reduced by this voltage gain. Noise processes associated with modulation of the collector to base capacitance, and within the bandwidth of the biasing circuitry, will similarly be reduced. Resistor R5 provides additional negative feedback to stabilize the oscillation circuit.
- the biasing circuitry extends down to DC, the oscillator frequency is also stabilized with respect to variation in temperature and parametric variations of the RF transistor.
- the circuit can be implemented from discrete devices or as an integrated circuit.
Landscapes
- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
- Oscillators With Electromechanical Resonators (AREA)
Abstract
An oscillator having: a transistor; a resonant circuit coupled between an output electrode of the transistor and a control electrode of the transistor; and a dc bias circuit for the transistor. The dc bias circuit comprises: a voltage producing circuit and a differential amplifier. The differential amplifier includes: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.
Description
Low Noise Oscillators
TECHNICAL FIELD
The present invention relates to RF oscillators and more particularly to RF oscillators having low levels of phase noise.
BACKGROUND
As is known in the art, low noise oscillators have a wide range of applications such as in navigation, radars and communication systems. As is also known in the art, with transistor oscillators, flicker noise from the transistors may significantly degrade oscillator phase noise. One technique used to produce low noise oscillators is to screen oscillator transistors for devices having low phase noise. This is time consuming, costly and can sometimes lead to unpredictable yields. Obtaining RF transistors with flicker noise much less than 1 kHz is desired, but is generally considered impractical. More particularly, RF oscillator phase noise is a dominant factor limiting the performance of many systems. A time based related attribute is the short-term stability or Allan variance. The basic mechanisms of phase noise generation in oscillators are well understood and described in the literature. An example is the model described D. B. Leeson in an article by D. B. Leeson, entitled "A simple model of feedback oscillator noise spectrum," Proc. IEEE, vol. 54, pp. 329-330, Feb. 1966. This oscillator model is commonly referred to as "Leeson's model". Many techniques are employed to reduce the phase noise of oscillators, but generally these techniques relate to using transistors with lower 1/f phase noise or higher Q resonators in the feedback circuit.
Phase noise is often described by its spectral properties. For example, phase noise can have a 1/f1 characteristic, with n being an integer. For oscillator circuits, n generally varies from 0 to 3. As described in by D. B. Leeson, in the paper entitled "A simple model of feedback oscillator noise spectrum," Proc. IEEE, vol. 54, pp. 329-330, Feb. 1966, electronic noise within the resonator bandwidth is increased such that flicker noise is converted into 1/f phase noise when the device is embedded into a high Q oscillator circuit. The implication of this conversion is that noise within the resonator bandwidth is
greatly increased. Obtaining lower phase noise then requires either lower 1/f phase noise transistors or higher Q resonators. In particular, the 1/f phase noise of a RF transistor relates to the phase noise at small offset frequencies from the center resonance frequency of the oscillation signal . For example, when referring to 1/f phase noise in a 1 GHz oscillator, the 1/f term applies to noise having a 1/f spectral shape when offset from the 1
GHz output. Although transistor 1/f phase noise is generally attributed to material and surface defects, the precise mechanisms are not well understood.
The origin of 1/f phase noise can be associated with the actual flicker noise of the transistor, but the specific mechanisms of conversion are also not well understood. Obtaining RF transistors having very low 1/f phase noise is quite difficult due to compromises between RF performance and flicker noise.
An analysis was presented by Eva S. Ferre-Pikal, Fred L. Walls, in a paper entitled Guidelines for Designing BJT Amplifiers with Low 1/f AM and PM noise, IEEE
Transactions on Ultrasonics, Ferroelectronics and Frequency Control, Vol. 44, No. 2, March 1997 which relates amplifier 1/f phase noise with low frequency voltage fluctuations. Modulation of the collector-base capacitance was proposed as a means of converting flicker noise to residual 1/f phase noise.
In a paper entitled Reduction of Phase Noise in Linear HBT Amplifiers Using
Low-Frequency Active Feedback by Eva S. Ferre-Pikal, IEEE Transactions on Circuits and Systems, Vol. 51 , No. 8, August 2004 the author attempted to stabilize a conventionally biased RF transistor by use of an instrumentation amplifier. The instrumentation amplifier was configured in a conventional topology. There was evidence that additional stability of the transistor bias point could suppress 1/f phase noise.
However this topology also introduced several additional resistive components as potential sources of noise and had limited noise suppression. These devices were not embedded into or related to low phase noise oscillators.
The desire is to provide an RF oscillator with very low phase noise. In addition, it is desired to minimize RF power variations with temperature and process variations.
SUMMARY In accordance with the present invention, an oscillator is provided having: a transistor; a resonant circuit coupled between an output electrode of the transistor and a
control electrode of the transistor; and a dc bias circuit for the transistor. The dc bias circuit comprises: a voltage producing circuit and a differential amplifier. The differential amplifier includes: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.
In one embodiment, the oscillator includes a voltage source having: one potential coupled to one terminal of the voltage producing circuit; and a second potential coupled to a second terminal of the voltage producing circuit; and wherein a third terminal of the voltage producing circuit is coupled to the second input of the differential amplifier.
In one embodiment, the voltage producing circuit includes a first resistor coupled between the first potential and the second input of the differential amplifier and a second resistor between an additional electrode of the transistor and the second potential. In one embodiment, the oscillator includes an inductor coupled between the second input of the differential amplifier and the output electrode of the transistor.
In one embodiment, the oscillator includes a capacitor coupled between the first input of the differential amplifier and the output of the differential amplifier.
In one embodiment, the oscillator includes a third resistor and a fourth resistor connected to the third resistor at a node, such node being coupled to the second potential through a capacitor, the third resistor being coupled between the output of the differential amplifier and the node and the fourth resistor being coupled between the node and the control electrode of the transistor.
In one embodiment, the fixed voltage is a voltage produced by a resistor divider coupled between the first and second potentials.
Thus, with such an arrangement, flicker noise of the oscillator is reduced by actively controlling biasing and low frequency modulation. This invention uses a novel topology to reduce flicker noise and improve phase noise. The technique is applicable to a broad class of oscillators. The details of one or more embodiments of the invention are set forth in the accompanying SINGLE FIGURE of an oscillator according to the invention and
description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWING
The SINGLE FIGURE is a schematic diagram of an RF oscillator according to the invention.
DETAILED DESCRIPTION
Referring now to the SINGLE FIGURE, an oscillator 10 is shown. The oscillator includes a transistor Ql; a resonant circuit 12 coupled between an output electrode, here collector electrode, of the transistor Ql and a control electrode, here base electrode, of the transistor Ql ; and a dc bias circuit 14 for the transistor Ql . The dc bias circuit 14 includes: a voltage producing circuit 16; and a differential amplifier 18. The differential amplifier 18 has: a first input (inverting (-) input) coupled to a fixed reference voltage; a second input (non- inverting (+)) coupled to the voltage producing circuit 16, such voltage producing circuit producing a voltage at the second input (non- inverting (+)) of the difference amplifier 18 related to current Ic passing through the output electrode
(collector) of the transistor Ql ; and an output 20 coupled to the control electrode (base) of the transistor QL A voltage source Vl has: one potential (+) coupled to one terminal of 22 the voltage producing circuit 14; and a second potential (-) coupled to a second terminal 24 of the voltage producing circuit 14. A third terminal 26 of the voltage producing circuit 14 is coupled to the second input (non-inverting (+)) of the differential amplifier 18. The voltage producing circuit 14 includes a first resistor R4 coupled between the first potential and the second input of the differential amplifier (non- inverting (+)) and a second resistor R5 between an additional electrode (emitter) of the transistor Ql and the second potential (i.e., terminal 24). An inductor Ll is coupled between the second input (non-inverting (+)) of the differential amplifierlδ and the output electrode (collector) of the transistor Ql . A capacitor C3 is coupled between the first input (inverting (-)) of the differential amplifier 18 and the output 20 of the differential amplifier 18. A third resistor R3 and a fourth resistor R6 are connected together at a node 30, such node 30 being coupled to the second potential (i.e., terminal 24) through a capacitor C4, the third resistor R3 being coupled between the output 20 of the differential amplifier 18 and the node 30 and the fourth resistor R6 being coupled
between the node 30 and the control electrode (base electrode) of the transistor Ql . The fixed voltage is a voltage produced at node 32 by a resistor divider 34 made up of resisters Rl and R2 coupled between the first and second potentials of the supply Vl . More particularly, the transistor Ql is the oscillator transistor. The differential amplifier 18 is chosen to have low flicker noise properties. A resistor R7 is the RF load resistor with typical value of 50 ohms. Inductor Ll is used for RF isolation and may also take the form of a distributed transmission line. Capacitor Cl is a bypass capacitor having very low reactance at the oscillation frequency. The two port device is the resonant feedback circuit 12 and could be a lumped element LC, an acoustic resonator such as SAW, or a distributed resonator such as a transmission line or a dielectric resonator. The two-port could include a means of tuning the oscillator frequency such as a varactor diode.
Here the differential amplifier 18 is used to bias and stabilize the oscillator transistor Ql . Transistor Ql is shown as a bipolar device, but may also be a FET; in which case the control electrode is the gate electrode. The semiconductor material may be silicon, GaAs, GaN or other semiconductor materials.
Biasing is provided by using as the differential amplifier 18 a differential amplifier having low flicker noise. For example, commercially available differential amplifiers are available with a typical flicker noise intercept of less than 10 Hz. A reference voltage formed by the voltage divider of Rl and R2 and also having low flicker noise is used as the inverting input, and a voltage proportional to collector current of the RF transistor is used as the non-inverting input. The feedback path from the voltage at the R4-L1 node is applied to the positive differential amp input due to the 180 phase shift of transistor Ql at low frequencies. Effectively the amplifier 19 positive input (non- inverting input (+)) becomes a negative feedback path, and the reference voltage at node 32 is applied to what is commonly used as the negative input to the op-amp. The output 20 from the differential amplifier 18 is used to provide a voltage for biasing the input (here emitter) to the RF transistor Ql . Resistor R3, R6 and capacitor C4 serve to isolate the RF signal from the biasing function. An additional capacitor C3 serves as a phase shift component to establish adequate phase margin and ensure that noise processes are not regenerated by the very high differential voltage gain. The biasing configuration
ensures that the voltage of the non-inverting input (+) of the differential amplifier 18 will be essentially equal to the voltage of the inverting input (-). Since the noise at the inverting input (-) is derived from a reference voltage at node 32 with very low noise, the noise at the non-inverting input (+) will also be similarly quiet. Any noise in the collector current Ic of the RF transistor Ql will now be sensed by the biasing circuit 14 and the voltage present at the base of the RF transistor Ql will be adjusted to compensate for that noise. Noise which is normally present at the collector of the RF transistor Ql will essentially be translated back to the base of said transistor Ql. However, since the transistor Ql has a voltage gain from the collector to base electrode, voltage noise will similarly be reduced by this voltage gain. Noise processes associated with modulation of the collector to base capacitance, and within the bandwidth of the biasing circuitry, will similarly be reduced. Resistor R5 provides additional negative feedback to stabilize the oscillation circuit.
Since the biasing circuitry extends down to DC, the oscillator frequency is also stabilized with respect to variation in temperature and parametric variations of the RF transistor. The circuit can be implemented from discrete devices or as an integrated circuit.
A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the invention applies to crystal, SAW, LC and microwave resonant oscillators, and can be implemented with discrete components or as integrated circuit devices. Additionally, inductors and capacitors could be replaced with equivalent function distributed elements, such as microstrip transmission lines, for use at microwave frequencies. Accordingly, other embodiments are within the scope of the following claims.
Claims
1. An oscillator comprising: a transistor; a resonant circuit coupled between an output electrode of the transistor and a control electrode of the transistor; a dc bias circuit for the transistor, such bias circuit comprising: a voltage producing circuit; a differential amplifier having: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.
2. The oscillator recited in claim 1 including a voltage source having: one potential coupled to one terminal of the voltage producing circuit; and a second potential coupled to a second terminal of the voltage producing circuit; and wherein a terminal of the voltage producing circuit is coupled to the second input of the differential amplifier.
3. The oscillator recited in claim 2 wherein the voltage producing circuit includes a first resistor coupled between the first potential and the second input of the differential amplifier and a second resistor between an additional electrode of the transistor and the second potential.
4. The oscillator recited in claim 3 includes an inductor coupled between the second input of the differential amplifier and the output electrode of the transistor.
5. The oscillator recited in claim 4 including a capacitor coupled between the first input of the differential amplifier and the output of the differential amplifier.
6. The oscillator recited in claim 3 including a third resistor coupled between the output of the amplifier and the control electrode of the transistor.
7. The oscillator recited in claim 3 including a third resistor and a fourth resistor connected to the third resistor at a node, such node being coupled to the second potential through a capacitor, the third resistor being coupled between the output of the differential amplifier and the node and the fourth resistor being coupled between the node and the control electrode of the transistor.
8. The oscillator recited in claim 3 wherein the fixed voltage is a voltage produced by a resistor divider coupled between the first and second potentials.
9. The oscillator recited in claim 8 includes an inductor coupled between the second input of the differential amplifier and the output electrode of the transistor.
10. The oscillator recited in claim 9 including a capacitor coupled between the first input of the differential amplifier and the output of the differential amplifier.
1 1. The oscillator recited in claim 8 including a third resistor coupled between the output of the amplifier and the control electrode of the transistor.
12. The oscillator recited in claim 8 including a third resistor and a fourth resistor connected to the third resistor at a node, such node being coupled to the second potential through a capacitor, the third resistor being coupled between the output of the differential amplifier and the node and the fourth resistor being coupled between the node and the control electrode of the transistor.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP09749301A EP2359468A1 (en) | 2008-11-24 | 2009-11-09 | Low noise oscillators |
JP2011537495A JP2012510205A (en) | 2008-11-24 | 2009-11-09 | Low noise oscillator |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/276,596 US20100127786A1 (en) | 2008-11-24 | 2008-11-24 | Low noise oscillators |
US12/276,596 | 2008-11-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010059445A1 true WO2010059445A1 (en) | 2010-05-27 |
Family
ID=41428443
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2009/063666 WO2010059445A1 (en) | 2008-11-24 | 2009-11-09 | Low noise oscillators |
Country Status (5)
Country | Link |
---|---|
US (1) | US20100127786A1 (en) |
EP (1) | EP2359468A1 (en) |
JP (1) | JP2012510205A (en) |
TW (1) | TW201036321A (en) |
WO (1) | WO2010059445A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014512155A (en) * | 2011-04-18 | 2014-05-19 | レイセオン カンパニー | Low noise oscillator |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8610517B2 (en) | 2010-11-02 | 2013-12-17 | Raytheon Company | Surface acoustic wave resonator mounting with low acceleration sensitivity |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5854578A (en) * | 1997-09-15 | 1998-12-29 | Motorola, Inc. | Active circuit having a temperature stable bias |
EP1473826A1 (en) * | 2003-04-29 | 2004-11-03 | Motorola Inc. | Wireless communication terminal and voltage controlled oscillator therefor |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6025754A (en) * | 1997-11-03 | 2000-02-15 | Harris Corporation | Envelope modulated amplifier bias control and method |
US7432772B2 (en) * | 2001-06-14 | 2008-10-07 | Telefonaktiebolaget L M Ericsson (Publ) | Electrical oscillator circuit and an integrated circuit |
US7113043B1 (en) * | 2004-06-16 | 2006-09-26 | Marvell International Ltd. | Active bias circuit for low-noise amplifiers |
US7292104B1 (en) * | 2005-02-11 | 2007-11-06 | Anadigics, Inc. | Variable gain amplifier |
US7348854B1 (en) * | 2006-04-28 | 2008-03-25 | Scientific Components Corporation | Automatic biasing and protection circuit for field effect transistor (FET) devices |
-
2008
- 2008-11-24 US US12/276,596 patent/US20100127786A1/en not_active Abandoned
-
2009
- 2009-11-09 EP EP09749301A patent/EP2359468A1/en not_active Withdrawn
- 2009-11-09 JP JP2011537495A patent/JP2012510205A/en active Pending
- 2009-11-09 WO PCT/US2009/063666 patent/WO2010059445A1/en active Application Filing
- 2009-11-16 TW TW098138857A patent/TW201036321A/en unknown
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5854578A (en) * | 1997-09-15 | 1998-12-29 | Motorola, Inc. | Active circuit having a temperature stable bias |
EP1473826A1 (en) * | 2003-04-29 | 2004-11-03 | Motorola Inc. | Wireless communication terminal and voltage controlled oscillator therefor |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014512155A (en) * | 2011-04-18 | 2014-05-19 | レイセオン カンパニー | Low noise oscillator |
Also Published As
Publication number | Publication date |
---|---|
JP2012510205A (en) | 2012-04-26 |
US20100127786A1 (en) | 2010-05-27 |
EP2359468A1 (en) | 2011-08-24 |
TW201036321A (en) | 2010-10-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2700157B1 (en) | Low noise oscillators | |
KR100756331B1 (en) | Low Phase Noise Differential LC tank VCO with Current Negative Feedback | |
US8792845B2 (en) | Oscillator | |
US20080129392A1 (en) | Colpitts quadrature voltage controlled oscillator | |
US7538630B2 (en) | Voltage controlled oscillator | |
US20080315964A1 (en) | Voltage controlled oscillator using tunable active inductor | |
US6091309A (en) | Tunable low noise oscillator using delay lines and ring mode trap filter | |
KR100843225B1 (en) | Voltage controlled oscillator for controlling phase noise and method using the voltage controlled oscillator | |
US20100127786A1 (en) | Low noise oscillators | |
Van Den Homberg | A universal 0.03-mm/sup 2/one-pin crystal oscillator in CMOS | |
US20120169429A1 (en) | Circuit arrangement for creating microwave oscillations | |
Jang et al. | A feedback GaN HEMT oscillator | |
RU2644067C1 (en) | Cascoded voltage-controlled generator | |
US7928810B2 (en) | Oscillator arrangement and method for operating an oscillating crystal | |
US5739729A (en) | Voltage-controlled LC oscillator | |
US7511590B1 (en) | Differential crystal oscillator | |
CN117713812B (en) | Broadband oscillator for phase-locked loop | |
Litovski | 6 Linear Oscillators | |
CN110417352B (en) | Stable constant current bias CASCODE MMIC VCO | |
CN114900130A (en) | Novel differential crystal oscillator circuit | |
JP2004104609A (en) | Temperature compensation type piezoelectric oscillator | |
EP1892826A1 (en) | Oscillator | |
US8933758B1 (en) | Bridge-stabilized oscillator with feedback control | |
Foit et al. | Broadband amplitude-stabilized oscillator | |
JPH07249940A (en) | Voltage controlled oscillator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09749301 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2011537495 Country of ref document: JP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2009749301 Country of ref document: EP |