Frequency synthesizer and frequency synthesis method thereof

Abstract

The invention relates to a brand-new full-band frequency generator for a multi-band orthogonal frequency division multiplexing ultrawideband (MB-OFDMUWB). The frequency generator generates all 14 frequencies which meet the requirement of the multi-band orthogonal frequency division multiplexing ultrawideband through a phase-locked loop and a main single sideband (SSB) mixer. The frequency generator generates three frequencies in one band group through one-time main single sideband mixing, the switching between the frequencies in the band group is controlled through an external digital signal, and the switching time of the frequencies depends on the switching time of a switch; and at the same time, the frequencies in different band groups are generated by controlling the frequency dividing ratio of a pre-divider, wherein the center frequencies in the band groups are generated by a local quadrature voltage-controlled oscillator. The full-band frequency generator has a simple structure and small area, saves a large quantity of electric current, can obtain desired frequencies directly through first-stage frequency conversion, and obtains higher spectrum purity.

Description

technical field [0001] The invention relates to a broadband RF communication system, in particular to a frequency synthesizer capable of meeting the MB-OFDM ultra-wideband standard. Background technique [0002] Wireless UWB technology is mainly used to realize short-distance, ultra-high-speed wireless communication, and its transmission distance is generally within 10m at present, and the transmission rate can reach 480Mb / s or even higher. The characteristics of UWB's high transmission rate, low power consumption and no interference with existing wireless systems make UWB a hot spot now and in the next five years. [0003] The U.S. Federal Communications Commission (FCC) allocates a spectrum range of 3.1GHz-10.6GHz for UWB, and the emission power spectral density shall not be greater than -41.2dBm / MHz. In view of the limitations of the process and the difficulty of high-frequency design, the initial interest is focused on the application of 3.1GHz-4.9GHz. The multi-band o...

AI Technical Summary

Problems solved by technology

However, the disadvantage of this scheme is that the accuracy of the quadrature signal depends on the single-sideband mixer, and factors such as layout mismatch and process deviation may cause the quadrature phase offset and amplitude imbalance of the carrier signal.

The inaccuracy of the orthogonal signal of the carrier, on the one hand, will increase the design difficulty of the direct conversion receiver and deteriorate the performance of the receiver; on the other hand, it will also affect the performance of the transmitter, making the Error Vector Magnitude (EVM) value System requirements not met

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