A High-Linearity LC Voltage-Controlled Oscillator Based on Mutual Inductance Compensation

Abstract

The present invention discloses a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation, which includes an LC oscillator. The LC oscillator is connected to an adjustable transconductance unit through a π / 2 phase shifter. The π / 2 phase shifter is implemented by an inductor load amplifier. The adjustable transconductance unit includes an adjustable current source. The input end of the adjustable current source is connected to an adjustable current source control voltage generation unit, and the adjustable transconductance unit is magnetically tuned by changing the bias current through the adjustable current source control voltage generation unit. By introducing a mutual inductance inductor, the equivalent variable inductor is adjusted by an adjustable current according to the principle of current-controlled magnetic tuning. A five-stage voltage bias circuit is used to convert the variable control voltage into a variable control current to dynamically compensate for the VCO gain change in different control voltage segments, greatly improving the linearity of the VCO gain without reducing the VCO tuning range.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor integrated circuit design, and particularly relates to a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation. Background Art

[0002] The traditional LC voltage-controlled oscillator changes the oscillation frequency by changing the control voltage of the voltage-controlled capacitor. The linear region of the MOS varactor used for the voltage-controlled capacitor is very small. For a VCO with a large tuning range to adapt to PVT variations, the designed VCO often has a large gain variation. Therefore, many techniques have been proposed to reduce the VCO gain variation to achieve higher linearity.

[0003] These techniques are roughly divided into two categories: The first category starts from adjusting the linear region of the variable capacitor to reduce the VCO gain variation. The VCO gain variation between tuning curves is reduced by a switched-capacitor array connected in series with the variable capacitor, which sacrifices the original adjustment range. In addition, the series switched-capacitor array reduces the Q value of the resonator; Another method not only optimizes the VCO gain variation of the same tuning curve by connecting variable capacitors with different biases in parallel, but also optimizes the VCO gain variation between different tuning curves by connecting a variable capacitor array with multi-bit control in parallel. The Q value of the branch with bias transfer is low, reducing the Q value of the resonator and affecting the phase noise; The second category optimizes the VCO gain variation by adjusting the inductor. An LC-tank with mutual inductance is added to the traditional LC-tank. By adjusting the capacitor array of the mutual inductance LC-tank, the change of the equivalent inductance is adjusted, and then the VCO gain variation between different tuning curves is optimized, but the adjustment granularity is limited. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation, which greatly improves the linearity of the VCO gain without reducing the VCO tuning range in view of the above-mentioned deficiencies in the prior art.

[0005] The present invention adopts the following technical solutions:

[0006] A high-linearity LC voltage-controlled oscillator based on mutual inductance compensation includes an LC oscillator. The LC oscillator is connected to an adjustable transconductance unit through a π / 2 phase shifter. The π / 2 phase shifter is implemented by an inductor load amplifier. The adjustable transconductance unit is connected to an adjustable current source control voltage generation unit through an adjustable current source. The control voltage Vctrl changes the bias current in the adjustable transconductance unit through the adjustable current source control voltage generation unit.

[0007] Specifically, the LC oscillator includes cross-coupled transistors M1 and M2. The sources of the cross-coupled transistors M1 and M2 are connected and grounded through a bias resistor R and a bypass capacitor C1. The drains of the cross-coupled transistors M1 and M2 are used as output terminals and connected to a π / 2 phase shifter.

[0008] Furthermore, the connection relationship of the cross-coupled transistors M1 and M2 is specifically as follows:

[0009] The gate of the cross-coupled transistor M1 is connected to the drain of the cross-coupled transistor M2, the gate of the cross-coupled transistor M2 is connected to the drain of the cross-coupled transistor M1. The drain of the cross-coupled transistor M1 is respectively connected to one end of an inductor Lp1 and one end of a Cvar, and the drain of M2 is respectively connected to one end of an inductor Lp2 and the other end of the Cvar. The other ends of the inductors Lp1 and Lp2 are connected to VDD_core.

[0010] Specifically, the π / 2 phase shifter includes amplifier transistors M3 and M4. The gates of the amplifier transistors M3 and M4 are respectively connected to the LC oscillator. The sources of the amplifier transistors M3 and M4 are grounded. The drains of the amplifier transistors M3 and M4 are respectively connected to an adjustable transconductance unit.

[0011] Furthermore, the drains of the amplifier transistors M3 and M4 are respectively connected to VDD_core through inductors Ld1 and Ld2.

[0012] Specifically, the adjustable transconductance unit includes amplifier transistors M5 and M6. The gates of the amplifier transistors M5 and M6 are respectively connected to the π / 2 phase shifter. The drains of the amplifier transistors M5 and M6 are respectively connected to VDD_core through inductors LS1 and LS2. The sources of the amplifier transistors M5 and M6 are respectively connected to the drains of an adjustable current source. The gate of the adjustable current source is connected to V in the adjustable current source control voltage generation unit. L1-5 connection.

[0013] Furthermore, the source of the adjustable current source is grounded.

[0014] Furthermore, the inductor Ls1 is mutually coupled with the inductor Lp1 in the LC oscillator, and Ls2 is mutually coupled with the inductor Lp2 in the LC oscillator.

[0015] Specifically, the voltage control range of the adjustable current source control voltage generation unit is 0.5 to 1.8V.

[0016] Furthermore, the adjustable current source control voltage generation unit includes V L1 、V L2 、V L3 、V L4 and V L5 ,specifically as follows:

[0017] V L1 : The gate of the NMOS transistor M7 is connected to C CTRL, the source of NMOS transistor M7 is grounded, and the drain of NMOS transistor M7 is connected to VDD_1p8 through resistor R1;

[0018] V L2 : the gate of NMOS transistor M8 is connected to C CTRL , the source is grounded, and the drain is connected to VDD_1p8 through resistor R2;

[0019] V L3 : the gate of NMOS transistor M9 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R3, and the other path is connected to the gate of M10. The source of NMOS transistor M10 is grounded, and the drain is connected to VDD_1p8 through resistor R4;

[0020] V L4 : the gate of NMOS transistor M11 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R5, and the other path is connected to the gate of NMOS transistor M12. The source of NMOS transistor M12 is grounded, and the drain is connected to VDD_1p8 through resistor R6;

[0021] V L5 : the gate of NMOS transistor M13 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R7, and the other path is connected to the gate of NMOS transistor M14. The source of NMOS transistor M14 is grounded, and the drain is connected to VDD_1p8 through resistor R8.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] A high-linearity LC voltage-controlled oscillator based on mutual inductance compensation, by introducing a mutual inductance inductor, adjusting the equivalent variable inductor through an adjustable current according to the principle of current-controlled magnetic tuning, and by introducing an adjustable bias current unit, compensating the tuning curve of the VCO in segments, so as to expand the adjustable range of the analog input voltage Vctrl corresponding to the linear region of the VCO. A voltage bias circuit is used to convert the variable control voltage into a variable control current to dynamically compensate for the change in the VCO gain in different control voltage segments, greatly improving the linearity of the VCO gain without reducing the tuning range of the VCO.

[0024] Furthermore, the cross-interconnection of M1 and M2 provides a negative resistance, enabling the LC oscillator to satisfy the Barkhausen criterion and achieve oscillation.

[0025] Furthermore, the sources of the cross-coupled transistors M1 and M2 are grounded through bias resistors R and bypass capacitors C1 respectively, which can reduce the phase noise of the VCO and thus improve the noise performance of the VCO. The drain outputs of the cross-coupled transistors are the final outputs, and a phase shifter is used to ensure that the currents flowing through the coupling inductors Lp and Ls have the same phase.

[0026] Furthermore, this setting provides a 90° phase shift and ensures that the currents flowing through the coupling inductors Lp and Ls have the same phase.

[0027] Furthermore, by adjusting the current flowing through Ls, the equivalent inductance value in the LC resonator can be changed, thereby compensating for the linearity of the VCO.

[0028] Furthermore, the larger the coupling coefficient, the lower the power consumption design of the circuit.

[0029] Furthermore, the voltage control range maintains a high linearity of 6.1% within 0.5 - 1.8V.

[0030] Furthermore, the setting of VL1 is to compensate for the linearity of the control voltage in the range of 0.5 - 0.6V, the setting of VL2 is to compensate for the linearity of the control voltage in the range of 0.6 - 0.8V, the setting of VL3 is to compensate for the linearity of the control voltage in the range of 1.2 - 1.4V, the setting of VL4 is to compensate for the linearity of the control voltage in the range of 1.4 - 1.6V, and the setting of VL5 is to compensate for the linearity of the control voltage in the range of 1.6 - 1.8V. Through these five-segment compensations, the linear range of the control voltage of the VCO is expanded.

[0031] In summary, the present invention designs a voltage conversion adjustable bias current circuit based on the principle of mutual inductance. By adjusting the equivalent inductance of the resonator, the linear range of the oscillator is expanded, enabling the module to adapt to the voltage domain of, for example, the loop filter in a phase-locked loop, and thus operating in a high-performance linear region.

[0032] Next, through the accompanying drawings and embodiments, the technical solutions of the present invention will be further described in detail. Brief Description of the Drawings

[0033] Figure 1 is the schematic diagram of the high-linearity LC voltage-controlled oscillator of the present invention;

[0034] Figure 2 is the I-V curve of the inductance-tuned current and control voltage and the C-V curve of the varactor of the present invention;

[0035] Figure 3 is the change curve diagram of the gain of the voltage-controlled oscillator affected by the tuned current and the varactor of the present invention respectively;

[0036] Figure 4Configuration diagram of the adjustable current source control voltage generation unit of the present invention;

[0037] Figure 5 Graph of the oscillation frequency and gain variation of a voltage - controlled oscillator after applying inductance - tuned current. Specific implementation manner

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0040] It should be understood that when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0041] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0042] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0043] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0044] Voltage-controlled oscillators (VCOs) are widely used in wireless and wired communication systems. Due to the high requirements of communication systems for clocks, VCOs are developing towards low noise, wide tuning range, low power consumption, and high gain linearity. When it plays a role in a phase-locked loop, the VCO gain (KVCO), as a frequency conversion gain, studies have shown that it directly affects the loop settling time and contributes to the loop noise.

[0045] The present invention provides a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation. Based on the 180nm CMOS process, a high-linearity LC voltage-controlled oscillator (LC-voltage-controlled oscillator, AMUX) for phase-locked loops and frequency modulation continuous waves is designed. A transformer structure is used to achieve a high mutual inductance coefficient, and the mutual inductance of the inductor is used to improve the linearity of the voltage-controlled oscillator. In addition, the present invention can achieve a very wide linear control voltage range to adapt to the voltage domains of other circuits.

[0046] Please refer to Figure 1 , a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation of the present invention includes a cross-coupled LC oscillator (M1 / M2), a π / 2 phase shifter (M3 / M4), an adjustable transconductance unit (M5 / M6), and an adjustable current source control voltage generation unit (M7~M14). The LC oscillator is connected to the adjustable transconductance unit via a π / 2 phase shifter implemented by an inductor load amplifier. The adjustable transconductance unit is connected to the adjustable current source control voltage generation unit through an adjustable current source. Magnetic tuning is performed by changing the bias current, thereby changing the effective inductance and improving the linearity.

[0047] The LC oscillator includes cross-coupled transistors M1 and M2, a bias resistor R, a bypass capacitor C1, and LC resonator inductors Lp1, Lp2, and Cvar.

[0048] The sources of cross-coupled transistors M1 and M2 are grounded through bias resistors R and bypass capacitors C1 respectively. The connection relationship of cross-coupled transistors M1 and M2 is as follows: the gate of M1 is connected to the drain of M2, the gate of M2 is connected to the drain of M1, the drain of M1 is connected to one end of inductor Lp1, one end of Cvar, and the gate of M3 in the π / 2 phase shifter respectively, the drain of M2 is connected to one end of inductor Lp2, the other end of Cvar, and the gate of M4 in the π / 2 phase shifter respectively, and the output of the LC oscillator is the drains of cross-coupled transistors M1 and M2; Cvar is connected in parallel between inductors Lp1 and Lp2, and the other ends of inductors Lp1 and Lp2 are connected to VDD_core.

[0049] The π / 2 phase shifter includes M3, M4, and inductors Ld1 and Ld2; the output of the LC oscillator is connected to the gate of M3 or M4 as the input of the π / 2 phase shifter. The drain of M3 is divided into two paths. One path is connected to VDD_core through inductor Ld1, and the other path is used as the output of the π / 2 phase shifter and is connected to the amplifying transistor M5 of the adjustable transconductance unit. The drain of M4 is divided into two paths. One path is connected to VDD_core through inductor Ld2, and the other path is used as the output of the π / 2 phase shifter and is connected to the amplifying transistor M6 of the adjustable transconductance unit. The sources of amplifying transistors M3 and M4 are grounded.

[0050] The adjustable transconductance unit includes amplifying transistors M5, M6, and an adjustable current source. The gates of amplifying transistors M5 and M6 are respectively connected to the π / 2 phase shifter through the output Q of the phase shifter. The drains of amplifying transistors M5 and M6 are respectively connected to VDD_core through inductors Ls1 and Ls2. The sources of amplifying transistors M5 and M6 are respectively connected to the drain of the adjustable current source. The adjustable current source is controlled by the output V L1-5 control, V L1-5 As the input of the adjustable current source, it is connected to the gate of the adjustable current source, and the source of the adjustable current source is grounded.

[0051] Among them, the coupling coefficients of inductors Ls1 and Ls2 with the inductors Lp1 and Lp2 of the LC oscillator are 0.9. By adjusting the current flowing through inductors Ls1 and Ls2, the equivalent inductance of the LC resonator is adjusted, thereby compensating the linearity of the resonator.

[0052] The adjustable current source control voltage generation unit includes five segments, specifically as follows:

[0053] V L1 Specifically: the gate of NMOS transistor M7 is connected to C CTRL , the source of NMOS transistor M7 is grounded, and the drain of NMOS transistor M7 is connected to the 1.8V voltage source VDD_1p8 through resistor R1;

[0054] V L2 Specifically: the gate of NMOS transistor M8 is connected to C CTRL, the source of NMOS transistor M8 is grounded, and the drain of NMOS transistor M8 is connected to VDD_1p8 through resistor R2;

[0055] V L3 Specifically: the gate of NMOS transistor M9 is connected to C CTRL , the drain of NMOS transistor M9 is connected to VDD_1p8, the source of NMOS transistor M9 is divided into two paths, one path is grounded through resistor R3, and the other path is connected to the gate of M10. The source of NMOS transistor M10 is grounded, and the drain of NMOS transistor M10 is connected to VDD_1p8 through resistor R4;

[0056] V L4 Specifically: the gate of NMOS transistor M11 is connected to C CTRL , the drain of NMOS transistor M11 is connected to VDD_1p8, the source of NMOS transistor M11 is divided into two paths, one path is grounded through resistor R5, and the other path is connected to the gate of NMOS transistor M12. The source of NMOS transistor M12 is grounded, and the drain of NMOS transistor M12 is connected to VDD_1p8 through resistor R6;

[0057] V L5 Specifically: the gate of NMOS transistor M13 is connected to C CTRL , the drain of NMOS transistor M13 is connected to VDD_1p8, the source of NMOS transistor M13 is divided into two paths, one path is grounded through resistor R7, and the other path is connected to the gate of NMOS transistor M14. The source of NMOS transistor M14 is grounded, and the drain of NMOS transistor M14 is connected to VDD_1p8 through resistor R8.

[0058] The output of the five-segment adaptive adjustable bias circuit is V L1-5 , which can provide a five-segment input-output conversion curve, thereby generating a five-segment variable current as shown in Figure 2 .

[0059] The working principle of a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to the present invention is specifically as follows:

[0060] By adjusting the current in the secondary coil Ls of the mutual coupling inductor, the equivalent inductance of the oscillator resonator is adjusted to compensate for the linearity and expand the analog control voltage range. The current in the secondary coil Ls is realized through a five-segment adjustable current source control voltage generation unit. The input of this module is the variable capacitance control voltage of the resonator, and different segments of voltage V L1-5 , V L1-5 are biased through a five-stage bias circuit to control and realize the variable current of the required secondary coil.

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0062] Please refer to Figure 2 , by introducing an adjustable current source to control the voltage generation unit, a tuning current-induced change in the gain of the voltage-controlled oscillator is created, which is opposite to the change in the gain of the voltage-controlled oscillator caused by the nonlinear variable capacitor. The control voltage range is 0.5 to 1.8 V, as Figure 3 shown.

[0063] Please refer to Figure 4 , which shows the configuration of the adjustable current source control voltage generation unit. Among them, two current branches controlled by V L1 and V L2 compensate for the nonlinearity in the 0.4 V to 0.8 V control voltage region, and the other three branches controlled by V L3 , V L4 and V L5 compensate for the nonlinearity in the 1.2 V to 1.8 V control voltage region.

[0064] Please refer to Figure 5 , the gain of the voltage-controlled oscillator after final compensation shows very little change in the wide control voltage range of 0.5 V to 1.8 V, only ±6.1%.

[0065] In summary, a high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to the present invention can achieve high linearity in a wide control voltage range of 1.3 V, and can provide ideas for solutions such as frequency modulation continuous wave radar solutions that require high-linearity adjustable clocks.

[0066] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the claims of the present invention.

Claims

1. A high-linearity LC voltage-controlled oscillator based on mutual inductance compensation, characterized in that, It includes an LC oscillator, which is connected to an adjustable transconductance unit via a π / 2 phase shifter. The π / 2 phase shifter is implemented by an inductor-loaded amplifier. The adjustable transconductance unit is connected to an adjustable current source control voltage generation unit via an adjustable current source. The control voltage Vctrl changes the bias current in the adjustable transconductance unit through the adjustable current source control voltage generation unit. The π / 2 phase shifter includes amplifying transistors M3 and M4. The gates of amplifying transistors M3 and M4 are respectively connected to the LC oscillator. The sources of amplifying transistors M3 and M4 are grounded. The drains of amplifying transistors M3 and M4 are respectively connected to the adjustable transconductance unit. The drains of amplifying transistors M3 and M4 are respectively connected to VDD_core via inductors Ld1 and Ld2. The adjustable transconductance unit includes amplifying transistors M5 and M6. The gates of amplifying transistors M5 and M6 are respectively connected to the π / 2 phase shifter. The drains of amplifying transistors M5 and M6 are respectively connected to VDD_core through inductors LS1 and LS2. The sources of amplifying transistors M5 and M6 are respectively connected to the drains of the adjustable current source. The gate of the adjustable current source is connected to V in the adjustable current source control voltage generation unit L1-5 connection; The voltage control range of the adjustable current source control voltage generation unit is 0.5~1.8V. The adjustable current source control voltage generation unit includes V L1 、V L2 、V L3 、V L4 and V L5 , specifically as follows: V L1 : The gate of NMOS transistor M7 is connected to C CTRL , the source of NMOS transistor M7 is grounded, and the drain of NMOS transistor M7 is connected to VDD_1p8 through resistor R1; V L2 : The gate of NMOS transistor M8 is connected to C CTRL , the source is grounded, and the drain is connected to VDD_1p8 through resistor R2; V L3 : The gate of NMOS transistor M9 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R3, and the other path is connected to the gate of M10. The source of NMOS transistor M10 is grounded, and the drain is connected to VDD_1p8 through resistor R4; V L4 : The gate of NMOS transistor M11 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R5, and the other path is connected to the gate of NMOS transistor M12. The source of NMOS transistor M12 is grounded, and the drain is connected to VDD_1p8 through resistor R6; V L5 : The gate of NMOS transistor M13 is connected to C CTRL , the drain is connected to VDD_1p8, the source is divided into two paths, one path is grounded through resistor R7, and the other path is connected to the gate of NMOS transistor M14. The source of NMOS transistor M14 is grounded, and the drain is connected to VDD_1p8 through resistor R8.

2. The high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to claim 1, wherein The LC oscillator includes cross-coupled transistors M1 and M2. The sources of cross-coupled transistors M1 and M2 are connected and grounded via a bias resistor R and a bypass capacitor C1. The drains of cross-coupled transistors M1 and M2 are used as output terminals and connected to the π / 2 phase shifter.

3. The high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to claim 2, wherein The connection relationship of cross-coupled transistors M1 and M2 is specifically as follows: The gate of cross-coupled transistor M1 is connected to the drain of cross-coupled transistor M2. The gate of cross-coupled transistor M2 is connected to the drain of cross-coupled transistor M1. The drain of cross-coupled transistor M1 is respectively connected to one end of inductor Lp1 and one end of Cvar. The drain of M2 is respectively connected to one end of inductor Lp2 and the other end of Cvar. The other ends of inductors Lp1 and Lp2 are connected to VDD_core.

4. The high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to claim 1, characterized in that The source of the adjustable current source is grounded.

5. The high-linearity LC voltage-controlled oscillator based on mutual inductance compensation according to claim 1, wherein Inductor Ls1 is mutually coupled with inductor Lp1 in the LC oscillator, and Ls2 is mutually coupled with inductor Lp2 in the LC oscillator.

Images