6results about How to "Improve Phase Noise Performance" patented technology

The embodiment of the present application discloses a frequency synthesis circuit and method, the circuit comprises: a power divider, the input end of the power divider is connected with a reference clock signal, for distributing the reference clock signal into multiple sub-reference signals, and outputting the multiple sub-reference signals through the corresponding output end of the power divider; wherein the multiple sub-reference signals are consistent in phase and equal in power; multiple phase-locked frequency multiplication channels, the input end of each phase-locked frequency multiplication channel is connected with the output end of the power divider correspondingly, and the phase-locked frequency multiplication channel is used for generating a first frequency signal after phase-locked frequency multiplication processing according to the corresponding sub-reference signal; a synthesis control module, the input end of the synthesis control module is connected with the output end of the multiple phase-locked frequency multiplication channels, and the synthesis control module is used for synthesizing the multiple first frequency signals to generate a final output signal. The technical scheme of the embodiment of the present application generates signals with the same frequency and phase correlation through the multiple phase-locked frequency multiplication channels, and improves the spectral purity of the signals.

This application provides an oscillator and a phase-locked loop (PLL) circuit. The oscillator includes a first LC resonant cavity, a second LC resonant cavity, and an inverting unit. A first input terminal and a second input terminal of a phase detection module are respectively connected to a first terminal and a second terminal of the resonant module. An output terminal outputs a detection signal. A first adjustment module, connected to the first LC resonant cavity, includes a first adjustable capacitor and / or a first adjustable inductor, and controls the values ​​of the first adjustable capacitor and / or the first adjustable inductor according to a received first control signal. A second adjustment module, connected to the second LC resonant cavity, includes a second adjustable capacitor and / or a second adjustable inductor, and controls the values ​​of the second adjustable capacitor and / or the second adjustable inductor according to a received second control signal. The first and second control signals are generated based on the detection signal. This oscillator reduces or eliminates flicker noise introduced by inconsistent resonant frequencies, improving the phase noise performance of the oscillator.

The invention relates to the field of integrated circuits, in particular to a low-phase-noise differential oscillator, a self-adaptive biasing circuit and application of the low-phase-noise differential oscillator and the self-adaptive biasing circuit. The oscillator adopts a Class-C architecture, and a self-adaptive bias circuit composed of two bias copy transistors, an integrating capacitor and a bias resistor is introduced. The self-adaptive biasing circuit and the Class-C oscillator can form a feedback loop, so that the differential crystal oscillator can reliably start oscillation in a C-type working mode; and the conduction angle of the cross coupling pair is limited in a relatively small range, so that extra noise is prevented from being introduced by an overlarge conduction angle. The adaptive biasing circuit can further reduce the pole frequency corresponding to a low-frequency additional resonance point introduced by the Class-C structure. Therefore, the problem that the differential crystal oscillator is difficult to give consideration to reliable oscillation starting and parasitic oscillation suppression is solved.

This invention relates to the field of integrated circuit technology, specifically to a Class F series resonant voltage-controlled oscillator, which consists of four identical unit circuits connected end to end to form a closed loop structure. Each unit circuit includes an active circuit and an LC series resonant network. The LC series resonant network includes a main resonant cavity and an auxiliary resonant cavity. This invention achieves a systematic improvement in phase noise performance through the series resonant topology and harmonic shaping mechanism.

The application discloses a dual-mode W-waveband voltage-controlled oscillator based on transformer magnetic tuning, which comprises two pairs of cross-coupled MOS transistors, a dual-mode six-coil transformer, a fine-tuning MOS transistor with a tuning switch, a coarse-tuning MOS transistor with a tuning switch and two pairs of output buffer stage MOS transistors; the change of the equivalent inductance value of a resonant cavity is realized by controlling the fine-tuning MOS transistor Msw1 and the fine-tuning MOS transistor Msw2; the fine-tuning MOS transistor Msw1 is turned on in a high-frequency band with small inductance and is turned off in a low-frequency band with large inductance; for fine frequency tuning without a varactor, the resistance of the fine-tuning MOS transistor Msw2 is changed by changing the gate voltage of the fine-tuning MOS transistor Msw2, so that fine tuning of the equivalent inductance is realized; the dual-mode six-coil transformer is used to replace a single-mode three-coil transformer, so that a four-frequency-band W-waveband voltage-controlled oscillator is realized. The application has higher resonant cavity Q value, can realize better phase noise and provides a high-quality local oscillator signal source for a W-waveband signal transceiving front end.

The application discloses a kind of digital control oscillator based on harmonic impedance tuning, including first MOS tube, second MOS tube, transformer with center tap, coarse adjustment capacitor group, middle adjustment capacitor group and harmonic impedance tuning network;The source of the first MOS tube is connected with the source of the second MOS tube, and the common point of source is grounded by harmonic impedance tuning network;The gate of the first MOS tube is connected with the drain of the second MOS tube, the drain of the first MOS tube is connected with the gate of the second MOS tube;The center tap of the transformer is connected with VDD power supply, and the two ends of the primary coil of transformer are respectively connected with the drain of the first MOS tube and the drain of the second MOS tube;The first end of the middle adjustment capacitor group is connected with the first end of the secondary coil of transformer, and the second end of middle adjustment capacitor group is connected to the second end of the secondary coil of transformer.The application has high resolution, monotonic frequency tuning, and can optimize phase noise performance.