Frequency synthesizer and frequency synthesizing method

Abstract

The embodiment of the invention provides a frequency synthesizer including a phase-locked loop (PLL) and a loop bandwidth controller. The PLL generates an output clock according to a reference clock. The loop bandwidth controller checks at least one indicator indicative of injection pulling / pushing of the PLL to configure a loop bandwidth of the PLL. In the embodiment, suppression / mitigation of injection pulling / pushing applied to the frequency synthesizer can be realized. A frequency synthesizing method is also provided.

Description

technical field [0001] The invention relates to frequency synthesis technology, in particular to a frequency synthesizer and a frequency synthesis method capable of suppressing / mitigating injection traction / propulsion. Background technique [0002] Frequency synthesizers are generally used in a wide variety of electronic devices. Taking a common wireless communication system as an example, an RF (Radio Frequency, radio frequency) PLL (Phase-Locked Loop, phase-locked loop) can be used as a frequency synthesizer. The frequency synthesizer generates an RF clock according to a baseband reference clock, and applies the RF clock to Subsequent launch components. However, due to certain factors, RFPLLs may suffer from injection pulling / pushing to produce disturbed RF clocks, where injection pulling can refer to changes in the oscillator frequency in RFPLLs due to load changes that deviate from the original The phenomenon of frequency, where the injection boost refers to the phenom...

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Problems solved by technology

However, due to certain factors, RFPLLs may suffer from injection pulling / pushing to generate disturbed RF clocks, where injection pulling can refer to changes in the oscillator frequency in RFPLLs due to load changes, deviating from the original The phenomenon of frequency, where injection boost refers to the phenomenon that the frequency of the oscillator in the RFPLL changes due to voltage fluctuations, and deviates from the original frequency

As an example, for the same transceiver, RFPLL and PA (Power Amplifier, power amplifier) ​​may be placed close to each other, resulting in the fact that the high-power RF signal generated by the PA may be injected into the controllable oscillator, thereby interfering with the clock frequency of the RF clock generated by the RFPLL

To give another example, in terms of electronic devices using multiple RF designs such as DSDA (Dual SIM Dual Active, dual-card dual-pass), CA (Carrier Aggregation, carrier aggregation) or IDC (In-Device Coexistence, coexistence in equipment), many two RF systems may be placed in close proximity to each other, with the result that a signal generated by at least one of the RFPLL and the PA in the second RF system may be injected into the controllable oscillator in the RFPLL in the first RF system, thereby Interfering with the clock frequency of the RF clock generated by the RFPLL in the first RF system

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