A frequency mixer and frequency mixing method

Abstract

The invention discloses a frequency synthesizer and a frequency synthesis method. The frequency synthesizer comprises: a large-stepping phase lock loop and a direct digital frequency synthesizer, an orthogonal mixer and a tracking phase lock loop. The orthogonal mixer is connected with the large-stepping phase lock loop and the digital frequency synthesizer respectively for mixing the frequency generated by the large-stepping phase lock loop and the low frequency generated by the direct digital frequency synthesizer to generate a single-sideband single tone; the tracking phase lock loop is connected with the orthogonal mixer for receiving the single-sideband single tone output by the orthogonal mixer and filtering the sideband leakage and oscillation leakage of the signal. The invention provides a frequency synthesizer with wide band width, small stepping, low stray and low noise and a frequency synthesis method. The invention has simple hardware structure and is easy to accomplish.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a frequency synthesizer and a frequency synthesis method in a radio frequency transceiver. Background technique [0002] Due to the rapid development of wireless communication technology in recent years, more and more attention has been paid to the design and research of integrated circuits in related fields. A frequency synthesizer is used to generate a local oscillator signal and is the most important module in the front end of a radio frequency transceiver. At present, the schemes for realizing small-step frequency synthesizers all use phase-locked loop (PLL). Phase-locked loop (PLL) is an automatic control circuit for the purpose of eliminating frequency error. An error, specifically, is a circuit that synchronizes an output signal (produced by an oscillator) with a reference or input signal in frequency and phase. A phase-locked loop is generally composed of...

AI Technical Summary

Problems solved by technology

Especially in the case of broadband and small steps, these two indicators are more difficult to achieve

There is a frequency synthesizer that can achieve broadband, low spurious, and small step performance. The implementation method is to add a lot of bandpass filters and perform filtering in sections. Although it can solve the low spurious and broadband problems at the same time, it makes the frequency Synthesizers complicate composition, hinder production and increase cost

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