CN111541423A - Low-phase-noise double-resonant-cavity noise filtering voltage-controlled oscillator - Google Patents

Abstract

The invention relates to a low-phase noise dual-resonator noise filtering voltage-controlled oscillator, which belongs to the technical field of microwave integrated circuit design. It is composed of a cross-coupled pair tube, a fixed capacitor array, a variable capacitor array, a source-drain coupling transformer and a second harmonic blocking circuit. The cross-coupled pair tube is composed of two symmetrical RF transistors, which are used to compensate the loss in the inductor-capacitor resonant cavity. The fixed capacitor array is composed of two pairs of capacitors controlled by external digital codes, and the variable capacitor array is composed of a pair of varactors. , The source-drain coupling transformer is composed of a very thick ninth metal layer winding in a 65nm process, and the second harmonic blocking circuit is composed of an inductance-capacitance resonant cavity that resonates at twice the carrier frequency. The invention adopts transformer-coupled source-drain to swing in the same direction to increase the swing amplitude of the oscillator, and a second harmonic suppression circuit is connected in series at the bottom of the oscillator to suppress the flicker noise caused by the second harmonic current in the oscillator. frequency conversion, thereby reducing the phase noise of the VCO.

Description

A Low Phase Noise Dual Resonator Noise Filtering Voltage Controlled Oscillator

technical field

The invention relates to a low-phase noise dual-resonator noise filtering voltage-controlled oscillator, which belongs to the technical field of microwave integrated circuit design.

Background technique

In recent years, the rapid development of automotive electronics and automotive millimeter-wave radar technology has gradually proved the application capability of millimeter-wave in automotive radar systems. In the future, cars will be equipped with multiple radars for detection in different directions. In order to reduce the cost of automotive radars, the signal transmission and data processing of radars must be integrated on a chip made by a complementary metal oxide (hereinafter referred to as CMOS) process. In the system, a high-frequency phase-locked loop is required to provide a pure local oscillator signal for reception and transmission to reduce the influence of phase noise on the accuracy of ranging and speed measurement.

For a CMOS phase-locked loop, the main sources of phase noise are charge pumps and voltage-controlled oscillators. Among them, the charge pump determines the in-band noise of the phase-locked loop, and the voltage-controlled oscillator determines the out-of-band noise of the phase-locked loop. However, we often find that the bandwidth of the phase-locked loop is only in the order of 100 kHz, and the phase noise of the voltage-controlled oscillator flicker noise in this frequency band is degraded by the up-conversion frequency and will be reflected in the overall performance. According to Hajimiri's 1998 article "A.Hajimiri and THLee,"Ageneral theory of phase noise in electrical oscillators,"in IEEE Journal of Solid-State Circuits,vol.33,no.2,pp.179-194,Feb. 1998. "In the ISF theory, the up-conversion of flicker noise will cause the asymmetry of the output waveform of the voltage-controlled oscillator and the increase of ISF _eff,dc , so some techniques need to be used to reduce it. 2016Mina Shahmohammadi in "M.Shahmohammadi,M.Babaie and RB Staszewski,"A 1/fNoise Upconversion Reduction Technique for Voltage-Biased RF CMOSOscillators,"in IEEE Journal of Solid-State Circuits,vol.51,no.11,pp.2610 -2624, Nov.2016." used a qualitative method to explain that the increase in ISF _eff,dc is mainly caused by the second harmonic current in the oscillating waveform.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a low phase noise dual resonator noise filter voltage controlled oscillator, which can reduce the ISF _eff,dc by suppressing the second harmonic current and improve the phase noise performance of the voltage controlled oscillator.

The low-phase noise dual-resonator noise filtering voltage-controlled oscillator proposed by the present invention includes cross-coupled pair tubes M1, M2, a fixed capacitor array, a variable capacitor array, a source-drain coupling transformer and a second harmonic blocking circuit; the The fixed capacitor array is connected in parallel with the variable capacitor array. The two ends of the fixed capacitor array and the variable capacitor array connected in parallel are respectively connected to the output node of the dual-resonator noise filtering voltage-controlled oscillator, and the output node is the cross-coupling pair tube. At the same time, the output node is connected to the outer ring port of the source-drain coupling transformer, the source of the source-drain coupling transformer is connected to the inner ring port of the source-drain coupling transformer, and the voltage bias tap of the source-drain coupling transformer is connected. p5 is connected to the power supply, the ground tap p6 of the source-drain coupling transformer is connected to one end of the second harmonic blocking circuit, and the other end of the second harmonic blocking circuit is grounded.

The above-mentioned dual-resonator noise filtering voltage-controlled oscillator, wherein:

The cross-coupling pair tube is composed of two symmetrical radio frequency transistors M1 and M2. The gate of the NMOS transistor M1 is connected to the input node p2 of the outer ring L1 of the transformer transformer of the source-drain coupling, and the drain of M1 is connected to the input of the outer ring L1 of the transformer. Node p1, the gate of the NMOS transistor M1 is connected to the input node p3 of the inner ring L2 of the source-drain coupling transformer; the gate of the NMOS transistor M2 is connected to the input node p1 of the outer ring L1 of the source-drain coupling transformer transformer, and the drain of M2 is connected to the source-drain coupling The input node p2 of the outer ring L1 of the transformer transformer, the gate of the NMOS transistor M2 is connected to the input node p4 of the inner ring L2 of the transformer transformer of the source-drain coupling, and the cross-coupling pair tube is used to compensate the loss in the inductor-capacitor resonant cavity to maintain oscillation;

The fixed capacitor array is composed of four capacitors C1, C2, C3 and C4, four resistors R1, R2, R3 and R4 which are respectively terminated with the four capacitors C1, C2, C3 and C4, and two switching transistors MC0. and MC1, and two inverters F0 and F1; the capacitor C1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the output end of the inverter F0, and the output end of the inverter F0 is connected to One end of the resistor R2 is connected to the other end of the resistor R2, the other end of the resistor R2 is connected to the drain of the switching transistor MC0, and the drain of the switching transistor MC0 is connected to the other end of the resistor R1 at the same time; one end of the capacitor C3 is connected to one end of the resistor R3, The other end of the resistor R3 is connected to the output end of the inverter F1, the output end of the inverter F1 is connected to one end of the resistor R4 at the same time, the other end of the resistor R4 is connected to the drain of the switching transistor MC1, and the drain of the switching transistor MC1 is connected. At the same time, it is connected to the other end of the resistor R3; when the digital control signal c0 = 1 is input from the outside of the oscillator, the other end of the capacitor C1 and the other end of the capacitor C2 are connected to the dual via the input ports p1 and p2. The resonant cavity of the resonant cavity noise filter voltage controlled oscillator; when the digital control signal c0=0, the other end of the capacitor C1 and the other end of the capacitor C2 are not connected to the resonant cavity, when the digital control signal c1=1, the capacitor C3 The other end and the other end of the capacitor C4 are connected to the resonant cavity through the input ports p2 and p1 of the external coil of the source-drain coupling transformer; when the digital control signal c1=0 input from the outside of the oscillator, the other end of the capacitor C3 and the capacitor The other end of C4 is not connected to the resonant cavity, and the fixed capacitor array is used to discretely adjust the oscillation frequency;

The variable capacitor array is composed of a varactor CV1, a varactor CV2, a varactor CV3 and a varactor CV4, wherein the gate terminal of the varactor CV1 is connected to the input port p1, and the body terminal of the varactor is connected to the control The terminal network cable 1, the gate terminal of the varactor CV2 is connected to the input port p2, the body terminal of the varactor CV2 is connected to the control terminal network cable 1, the gate terminal of the varactor CV3 is connected to the input port p3, and the body terminal of the varactor CV3 is connected to the control terminal. The terminal network cable 1, the gate terminal of the varactor CV4 is connected to the input port p4, and the body terminal of the varactor CV4 is connected to the control terminal network cable 1; the variable capacitor array is used to continuously adjust the oscillation frequency;

The source-drain coupling transformer includes 6 ports: the two output ports p1 and p2 of the outer ring L1 are respectively connected to the radio frequency transistors M1 and M2 of the cross-coupling pair of tubes, and the two output ports p3 and p4 of the inner ring L2 are connected to the cross-coupling pair. The source of the tube is connected, the voltage bias tap p5 of the source-drain coupling transformer is connected to the power supply, and the tap ground p6 is grounded; the source-drain coupling transformer is used to form an oscillation waveform with the same direction of source and drain;

The second harmonic blocking circuit is composed of inductor-capacitor resonant cavities Ls and Cs, the inductor-capacitor resonant cavity Ls is connected in parallel with the inductor-capacitor Cs, and one end of the inductor-capacitor resonant cavity Ls and the inductor-capacitor Cs in parallel is connected to the tap of the source-drain coupling transformer. The ground p6 is connected, one end of the inductance-capacitor resonant cavity Ls and the inductance-capacitor Cs are connected in parallel and the other end is grounded; the second harmonic blocking circuit is used to suppress the second harmonic current in the oscillator.

The dual-resonator noise filtering voltage-controlled oscillator with low phase noise proposed by the present invention has the following advantages:

1. In the low-phase noise dual-resonator noise filtering voltage-controlled oscillator of the present invention, the source-drain co-directional swing brought by transformer coupling is used to increase the swing of the oscillator, thus reducing the phase noise of the voltage-controlled oscillator .

2. The present invention adopts the method of connecting the second harmonic suppression circuit in series at the bottom of the oscillator, so as to suppress the frequency conversion on the flicker noise caused by the second harmonic, and further reduce the phase noise of the voltage controlled oscillator.

Description of drawings

FIG. 1 is a circuit schematic diagram of a dual-resonator noise filtering voltage-controlled oscillator with low phase noise proposed by the present invention.

FIG. 2 is a structural diagram of a fixed capacitor array in the dual-cavity noise filtering voltage-controlled oscillator of the present invention.

Figure 3 is a comparison diagram of the ISF function of the voltage-controlled oscillator before and after using the second harmonic blocking circuit.

Figure 4 is a comparison diagram of the phase noise of the voltage-controlled oscillator before and after the second harmonic blocking circuit is adopted.

Detailed ways

The low-phase noise dual-resonator noise filtering voltage-controlled oscillator proposed by the present invention, its circuit schematic diagram is shown in Figure 1, including a cross-coupled pair tube, a fixed capacitor array, a variable capacitor array, a source-drain coupling transformer and a secondary A harmonic blocking circuit; the fixed capacitor array is connected in parallel with the variable capacitor array, and the two ends of the fixed capacitor array and the variable capacitor array connected in parallel are respectively connected to the output nodes of the double-resonator noise filtering voltage-controlled oscillator. The node is the drain of the cross-coupling pair tube. At the same time, the output node is connected to the outer ring port of the source-drain coupling transformer. The source of the source-drain coupling transformer is connected to the inner ring port of the source-drain coupling transformer. The voltage bias tap of the coupling transformer is connected to the power supply, the ground tap of the source-drain coupling transformer is connected to one end of the second harmonic blocking circuit, and the other end of the second harmonic blocking circuit is grounded.

In the above-mentioned dual-resonator noise filtering voltage-controlled oscillator:

The cross-coupling pair tube is composed of two symmetrical radio frequency transistors M1 and M2. The gate of the NMOS transistor M1 is connected to the input node p2 of the outer ring L1 of the transformer transformer of the source-drain coupling, and the drain of M1 is connected to the input of the outer ring L1 of the transformer. Node p1, the gate of the NMOS transistor M1 is connected to the input node p3 of the inner ring L2 of the source-drain coupling transformer; the gate of the NMOS transistor M2 is connected to the input node p1 of the outer ring L1 of the source-drain coupling transformer transformer, and the drain of M2 is connected to the source-drain coupling The input node p2 of the outer ring L1 of the transformer transformer, the gate of the NMOS transistor M2 is connected to the input node p4 of the inner ring L2 of the transformer transformer of the source-drain coupling, and the cross-coupling pair tube is used to compensate the loss in the inductor-capacitor resonant cavity to maintain oscillation;

The circuit schematic diagram of the fixed capacitor array is shown in Figure 2, consisting of four capacitors C1, C2, C3, C4, and four resistors R1, R2 terminated with the four capacitors C1, C2, C3, and C4 respectively. , R3, R4, two switching transistors MC0 and MC1, and two inverters F0 and F1. The capacitor C1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the output end of the inverter F0, the output end of the inverter F0 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the switching transistor. The drain of MC0 is connected to the drain of the switching transistor MC0, and the drain of the switching transistor MC0 is connected to the other end of the resistor R1 at the same time; one end of the capacitor C3 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the output of the inverter F1. The output end of the phase device F1 is connected to one end of the resistor R4 at the same time, the other end of the resistor R4 is connected to the drain of the switching transistor MC1, and the drain of the switching transistor MC1 is connected to the other end of the resistor R3 at the same time; When the digital control signal c0=1 input from the outside of the device, the other end of the capacitor C1 and the other end of the capacitor C2 are connected to the resonant cavity of the dual-resonator noise filtering voltage-controlled oscillator through the input ports p1 and p2; when the digital control signal When c0=0, the other end of the capacitor C1 and the other end of the capacitor C2 are not connected to the resonant cavity. When the digital control signal c1=1, the other end of the capacitor C3 and the other end of the capacitor C4 pass through the source-drain coupling transformer external coil. The input ports p2 and p1 are connected to the resonant cavity; when the digital control signal c1=0 input from the outside of the oscillator, the other end of the capacitor C3 and the other end of the capacitor C4 are not connected to the resonant cavity, and the fixed capacitor array Used to discretely adjust the oscillation frequency;

The variable capacitor array is composed of a varactor CV1, a varactor CV2, a varactor CV3 and a varactor CV4, wherein the gate end of the varactor CV1 is connected to the input port p1, and the body end of the varactor is connected to The control end network cable 1, the gate end of the varactor CV2 is connected to the input port p2, the body end of the varactor CV2 is connected to the control end network cable 1, the gate end of the varactor CV3 is connected to the input port p3, and the body end of the varactor CV3 is connected The control terminal network cable 1, the gate terminal of the varactor CV4 is connected to the input port p4, and the body terminal of the varactor CV4 is connected to the control terminal network cable 1. A variable capacitor array is used to continuously adjust the oscillation frequency;

The source-drain coupling transformer is composed of a very thick ninth metal layer winding in a 65nm process, and includes 6 ports: the two output ports p1 and p2 of the outer ring L1 are respectively connected to the radio frequency transistors M1 and M2 of the cross-coupled pair of tubes. , the two output ports p3 and p4 of the inner ring L2 are connected to the source of the cross-coupled pair tube, the voltage bias tap p5 of the source-drain coupling transformer is connected to the power supply, and the tap ground p6 is grounded; the source-drain coupling transformer is used to form Oscillation waveform with the same direction of source and drain;

The second harmonic blocking circuit is composed of inductor-capacitor resonant cavities Ls and Cs that resonate at twice the carrier frequency. One end is connected to the tap ground p6 of the source-drain coupling transformer, and the other end of the inductance-capacitor resonant cavity Ls is connected to the inductance-capacitor Cs in parallel, and the other end is grounded; the second harmonic blocking circuit is used to suppress the second harmonic current in the oscillator .

In order to make the purpose, technical scheme and characteristics of the present invention clearer and clearer, detailed description and description are carried out below in conjunction with the accompanying drawings:

As shown in FIG. 1 , the low phase noise dual-resonator noise filtering voltage-controlled oscillator of the present invention is composed of a cross-coupled pair tube, a fixed capacitor array, a variable capacitor array, a source-drain coupling transformer and a second harmonic blocking circuit. . The cross-coupled transistor consists of two symmetrical TSMC CMOS 65nm nmos_25ud18 RF transistors, whose gates and drains are connected to each other's drains and gates through metal wires, respectively, to compensate for the loss in the inductor-capacitor resonant cavity to maintain oscillation. The fixed capacitor array is composed of capacitors controlled by a 2-digit digital code. The digital control capacitor can be controlled by an external digital control code to connect to the oscillator resonant cavity. The digital control capacitor is controlled by an external digital control code. , the lower the oscillation frequency. The variable capacitor array is composed of a pair of varactors. The varactor is a kind of reflex transistor whose source and drain are N-type heavily doped and the well is N-type lightly doped. Its capacitance varies with the gate-to-body voltage. The connection method of the varactor in the oscillator is that the gate is connected to the output node, and the body terminal is connected to the control voltage node. Therefore, the greater the control voltage, the smaller the gate-to-body voltage, and the varactor is connected to The smaller the capacitance into the resonant cavity, the higher the oscillation frequency. The source-drain coupling transformer is composed of a very thick ninth metal layer winding in the 65nm process, and includes 6 ports: the 2 ports (p1, p2) of the outer ring are connected to the drain of the coupled pair of tubes, and the 2 ports of the inner ring ( p3, p4) are connected to the source of the coupled pair of tubes, 1 tap voltage bias point (p5), 1 tap ground (p6); the second harmonic blocking circuit is doubled by a smaller resonance at the carrier frequency The second harmonic blocking circuit can suppress the second harmonic current in the oscillator, thereby suppressing the up-conversion of flicker noise and improving the phase noise performance; the specific connection methods are as follows:

The cross-coupled pair transistor shown in FIG. 1 is composed of transistors M1 and M2, wherein the transistors M1 and M2 are NMOS transistors. The gate of the NMOS transistor M1 is connected to the input node p2 of the transformer outer ring L1, the drain of M1 is connected to the input node p1 of the transformer outer ring L1, the gate of the NMOS transistor M1 is connected to the input node p3 of the transformer inner ring L2; The gate is connected to the input node p1 of the transformer outer ring L1, the drain of M2 is connected to the input node p2 of the transformer outer ring L1, and the gate of the NMOS transistor M2 is connected to the input node p4 of the transformer inner ring L2. The variable capacitor array shown in Figure 1 is composed of varactors CV1, CV2, CV3, and CV4. The gate terminal of the varactor CV1 is connected to p1, and the body terminal is connected to the network cable 1 of the control terminal; the gate terminal of the varactor CV2 is connected to p2. The body end is connected to the control end network cable 1; the varactor CV3 grid end is connected to p3, and the body end is connected to the control end network cable 1; the varactor CV4 grid end is connected to p4, and the body end is connected to the control end network cable 1. The fixed capacitor array shown in FIG. 1 is shown in detail in FIG. 2 .

The fixed capacitor array shown in Figure 2 consists of capacitors C1, C2, C3, and C4, four resistors R1, R2, R3, and R4 that are respectively terminated with them, two switching transistors MC0 and MC1, and two inverters Formed by F0 and F1; the capacitor C1 is connected to the resistor R1, the resistor R1 is connected to the output end of the inverter F0, the output end of the inverter F0 is connected to the resistor R2, and the resistor R2 is connected to the The switch transistor MC0 is connected to the switch transistor MC0, and the switch transistor MC0 is connected to the resistor R1; the capacitor C3 is connected to the resistor R3, the resistor R3 is connected to the output end of the inverter F1, and the inverter F1 The output terminal is connected to the resistor R4, the resistor R4 is connected to the switching transistor MC1, and the switching transistor MC1 is connected to the resistor R3; when the digital control signal c0=1 input from the outside of the oscillator, the The capacitor C1 and the capacitor C2 are connected to the resonant cavity of the dual-resonator noise filtering voltage-controlled oscillator through the input ports p1 and p2; when the digital control signal c0=0, the capacitor C1 and the capacitor C2 are not connected to the resonant cavity. When the control signal c1=1, the capacitor C3 and the capacitor C4 are connected to the resonant cavity through the input ports p1 and p2; when the digital control signal c1=0 input from the outside of the oscillator, the capacitor C3 and the capacitor C4 are not connected a resonant cavity; the fixed capacitance array is used for discretely adjusting the oscillation frequency;

The source-drain coupling transformer shown in Figure 1 is composed of a very thick ninth metal layer winding in the 65nm process, and includes 6 ports: the 2 ports (p1, p2) of the outer ring are connected to the drain of the coupling pair tube, and the inner ring 2 ports (p3, p4) are connected to the source of the coupling pair, 1 tap voltage bias point (p5), 1 tap ground (p6); the value range of the coupling coefficient k of the two coils is 0.4～ 0.3.

The second harmonic blocking circuit shown in Figure 1 is composed of a small inductance-capacitor resonant cavity (Ls, Cs) that resonates at twice the carrier frequency; Ls and Cs are connected in parallel, one end is connected to the p6 port, and the other end is grounded; The second harmonic blocking circuit can suppress the second harmonic current in the oscillator, thereby suppressing the up-conversion of flicker noise and improving the phase noise performance.

In an embodiment of the present invention, a 65nm CMOS process (which is a conventional manufacturing process in the technical field) is used to prepare a dual-resonator noise filtering voltage-controlled oscillator circuit with low phase noise. The simulation results are shown in FIG. 3 and FIG. 4 . Among them, Figure 3 is a comparison diagram of the ISF function of the voltage-controlled oscillator before and after using the second harmonic blocking circuit. After the use of the second harmonic blocking circuit, it can be seen that the ISF function decreases as a whole, and its average value also decreases. The degree of phase noise should be reduced, which can be verified by Figure 4; Figure 4 is a comparison chart of the phase noise of the VCO before and after using the second harmonic blocking circuit. The phase noise level decreases after the second harmonic blocking circuit is used. It can be seen from FIG. 3 and FIG. 4 that the voltage-controlled oscillator circuit proposed by the present invention can improve the phase noise performance of the conventional voltage-controlled oscillator circuit.

The above embodiments verify the correctness and effectiveness of the present invention. The above description is only the low phase noise capacitor inductance voltage controlled oscillator of the present invention under a specific CMOS process and a specific frequency band, but is not intended to limit the protection scope of the present invention.

Claims (2)

1. a low phase noise dual resonator noise filter voltage controlled oscillator, it is characterized in that the dual resonator noise filter voltage controlled oscillator comprises a cross-coupling pair of tubes M1, M2, a fixed capacitor array, a variable capacitor array, a source-drain A coupling transformer and a second harmonic blocking circuit; the fixed capacitor array is connected in parallel with the variable capacitor array, and the two ends of the fixed capacitor array and the variable capacitor array connected in parallel are respectively connected to the output of the dual-resonator noise filtering voltage-controlled oscillator node, the output node is the drain of the cross-coupled pair tube, and the output node is connected to the outer ring port of the source-drain coupling transformer respectively, the source of the source-drain coupling transformer and the inner ring port of the source-drain coupling transformer The voltage bias tap p5 of the source-drain coupling transformer is connected to the power supply, the ground tap p6 of the source-drain coupling transformer is connected to one end of the second harmonic blocking circuit, and the other end of the second harmonic blocking circuit is grounded. 2. The dual-resonator noise filtering voltage-controlled oscillator according to claim 1, wherein: The cross-coupling pair tube is composed of two symmetrical radio frequency transistors M1 and M2. The gate of the NMOS transistor M1 is connected to the input node p2 of the outer ring L1 of the transformer transformer of the source-drain coupling, and the drain of M1 is connected to the input of the outer ring L1 of the transformer. Node p1, the gate of the NMOS transistor M1 is connected to the input node p3 of the inner ring L2 of the source-drain coupling transformer; the gate of the NMOS transistor M2 is connected to the input node p1 of the outer ring L1 of the source-drain coupling transformer transformer, and the drain of M2 is connected to the source-drain coupling The input node p2 of the outer ring L1 of the transformer transformer, the gate of the NMOS transistor M2 is connected to the input node p4 of the inner ring L2 of the transformer transformer of the source-drain coupling, and the cross-coupling pair tube is used to compensate the loss in the inductor-capacitor resonant cavity to maintain oscillation; The fixed capacitor array is composed of four capacitors C1, C2, C3 and C4, four resistors R1, R2, R3 and R4 which are respectively terminated with the four capacitors C1, C2, C3 and C4, and two switching transistors MC0. and MC1, and two inverters F0 and F1; the capacitor C1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the output end of the inverter F0, and the output end of the inverter F0 is connected to One end of the resistor R2 is connected to the other end of the resistor R2, the other end of the resistor R2 is connected to the drain of the switching transistor MC0, and the drain of the switching transistor MC0 is connected to the other end of the resistor R1 at the same time; one end of the capacitor C3 is connected to one end of the resistor R3, The other end of the resistor R3 is connected to the output end of the inverter F1, the output end of the inverter F1 is connected to one end of the resistor R4 at the same time, the other end of the resistor R4 is connected to the drain of the switching transistor MC1, and the drain of the switching transistor MC1 is connected. At the same time, it is connected to the other end of the resistor R3; when the digital control signal c0 = 1 is input from the outside of the oscillator, the other end of the capacitor C1 and the other end of the capacitor C2 are connected to the dual via the input ports p1 and p2. The resonant cavity of the resonant cavity noise filter voltage controlled oscillator; when the digital control signal c0=0, the other end of the capacitor C1 and the other end of the capacitor C2 are not connected to the resonant cavity, when the digital control signal c1=1, the capacitor C3 The other end and the other end of the capacitor C4 are connected to the resonant cavity through the input ports p2 and p1 of the external coil of the source-drain coupling transformer; when the digital control signal c1=0 input from the outside of the oscillator, the other end of the capacitor C3 and the capacitor The other end of C4 is not connected to the resonant cavity, and the fixed capacitor array is used to discretely adjust the oscillation frequency; The variable capacitor array is composed of a varactor CV1, a varactor CV2, a varactor CV3 and a varactor CV4, wherein the gate terminal of the varactor CV1 is connected to the input port p1, and the body terminal of the varactor is connected to the control The terminal network cable 1, the gate terminal of the varactor CV2 is connected to the input port p2, the body terminal of the varactor CV2 is connected to the control terminal network cable 1, the gate terminal of the varactor CV3 is connected to the input port p3, and the body terminal of the varactor CV3 is connected to the control terminal. The terminal network cable 1, the gate terminal of the varactor CV4 is connected to the input port p4, and the body terminal of the varactor CV4 is connected to the control terminal network cable 1; the variable capacitor array is used to continuously adjust the oscillation frequency; The source-drain coupling transformer includes 6 ports: the two output ports p1 and p2 of the outer ring L1 are respectively connected to the radio frequency transistors M1 and M2 of the cross-coupling pair of tubes, and the two output ports p3 and p4 of the inner ring L2 are connected to the cross-coupling pair. The source of the tube is connected, the voltage bias tap p5 of the source-drain coupling transformer is connected to the power supply, and the tap ground p6 is grounded; the source-drain coupling transformer is used to form an oscillation waveform with the same direction of source and drain; The second harmonic blocking circuit is composed of inductor-capacitor resonant cavities Ls and Cs, the inductor-capacitor resonant cavity Ls is connected in parallel with the inductor-capacitor Cs, and one end of the inductor-capacitor resonant cavity Ls and the inductor-capacitor Cs in parallel is connected to the tap of the source-drain coupling transformer. The ground p6 is connected, one end of the inductance-capacitor resonant cavity Ls and the inductance-capacitor Cs are connected in parallel and the other end is grounded; the second harmonic blocking circuit is used to suppress the second harmonic current in the oscillator.

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