Lock phase loop frequency mixer

Abstract

The invention discloses a phase-locked loop frequency synthesizer which is characterized in that the phase-locked loop frequency synthesizer comprises a phase-frequency phase discriminator, a charge pump, a low-pass filter, a broadband differential LC oscillator provided with a capacitor array of a control switch, a multimode frequency divider and a controller which is used for a self-adapting frequency regulating curve; the analogue signal control end of the broadband differential LC oscillator is connected with an output signal Vctrl of the low-pass filter, and the digital signal control end thereof is connected with the output end of the controller. The phase-locked loop frequency synthesizer further comprises a 3-order full digital Sigma-delta modulator provided with a three-bit quantizer. The phase-locked loop frequency synthesizer can realize fractional frequency division, and the output frequency signals thereof can be continuously changed at a wide range, and the precision of the frequency spectrum is high.

Description

technical field [0001] The invention belongs to the technical field of electronic communication and radio frequency, and relates to a phase-locked loop frequency synthesizer. Background technique [0002] In the application of modern wireless communication systems and radio frequency circuits, the phase-locked loop frequency synthesizer has become a very important part. With the development of technology, many high-performance and low-cost frequency synthesizers have emerged. There are two types of high-performance integrated PLL frequency synthesizers: integer frequency synthesizers and fractional frequency synthesizers. Integer frequency synthesizers have loop bandwidth and channel span constraints. Compared with fractional frequency synthesizers, they can obtain larger system loop bandwidth, smaller adjustment time and smaller frequency span; at the same time, they can also get High output spectral purity and low phase noise performance. [0003] In modern wireless com...

AI Technical Summary

Problems solved by technology

In addition, due to the mismatch of multiple phases, certain spurious signals will be generated in the output of these frequency synthesizers and frequency dividers, which will have a bad influence on normal high-speed wireless communication.

[0004] From the above, it can be seen that the existing frequency synthesizers all have room for improvement, and cannot take into account the performance of spectrum accuracy, frequency range and channel frequency spacing.

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