4results about How to "Improve Phase Noise Performance" patented technology

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 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.