High-precision high-linearity digital-analoge mixed signal loop pressure control oscillator

Abstract

The disclosed oscillator consists of two parts: delay cells connected in ring, and control circuit for digital-analog composite signal (scheme 1); or delay cells connected in ring, and a digital control circuit (scheme 2). In scheme 1, delay cell is a common difference inverter; the control circuit for digital-analog composite signal is composed of a set of constant current sources with different currents and an active load MOS tube. In scheme 2, the digital control circuit is same as the part of digital control circuit in scheme 1; load tube of delay unit is composed of multiple pairs of load tube. Being controlled by digital signal control circuit, one pair of load tube is in use for presetting frequency or coarse adjusting frequency; being controlled by analog signal, another pair of load tube is in use for adjusting frequency accurately. The invention is applicable to modern communication, digital circuit, and other electronic information processing system.

Description

technical field [0001] The invention relates to the technical field of phase-locked loops used in communication and information processing systems, in particular to a high-precision and high-linearity digital-analog mixed signal loop voltage-controlled oscillator. Background technique [0002] The voltage-controlled oscillator (VCO) is the most important component in the phase-locked loop. In order to obtain high-frequency, high-precision output frequency, the form of an LC voltage-controlled oscillator or a loop voltage-controlled oscillator is generally used. LC voltage-controlled oscillator has low phase noise and has been widely used in the field of wireless communication with high noise index requirements. However, it also has disadvantages such as large power consumption, not wide output frequency range, large area occupied by integrated inductors, and low manufacturing process precision. . The loop voltage controlled oscillator has also been widely used in communicat...

AI Technical Summary

Problems solved by technology

[0004] A disadvantage of the above-mentioned common loop voltage-controlled oscillator is that the gain Kv of the VCO is too high, and a small external voltage change will cause a large output signal frequency change. In the application as a phase-locked loop, it will cause fluctuations in the power supply, Substrate noise, and the charge pump and phase detector noise immunity from the loop filter are poor, which is very unfavorable for applications in wireless communications where phase noise requirements are extremely low

[0005] In order to reduce Kv and speed up the locking speed of the phase-locked loop, many VCOs with digital presets or digital coarse adjustments have been proposed, but they all have the disadvantages of low digital coarse adjustments or digital presets, which will greatly reduce The effect of speeding up the lock

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