Frequency Synthesizer for Dual Channel Multimode RF Receiver

Abstract

The invention relates to a frequency synthesizer for a dual-channel multi-mode radio frequency receiver, comprising a shared frequency and phase detector, a charge pump, a loop filter and a feedback frequency divider; wherein, the shared frequency and phase detector Phase device, charge pump and loop filter are respectively connected to two sets of voltage controlled oscillators and isolation amplifiers, and then connected to the frequency and phase detector through the shared feedback frequency divider to form the first and second phase-locked loops two feedback loops. The chip area of ​​the frequency synthesizer of the present invention is smaller, the current consumption is lower, and the mutual interference between sub-modules can also be effectively reduced. The first and second phase-locked loops provide two independent local oscillator frequency signals, which are respectively output to the mixers of the two signal channels, so that the two signals in the dual-channel multimode radio frequency receiver The channels can operate independently to realize, for example, the receiving and processing of two sets of radio frequency signals under different communication standards.

Description

technical field [0001] The invention relates to a frequency synthesizer, in particular to a frequency synthesizer for a dual-channel multi-mode radio frequency receiver. Background technique [0002] Frequency synthesizers are mostly used in wireless communication RF chips, digital signal processing chips, analog signal processing chips, and mixed signal processing chips to provide tunable local oscillator frequencies for RF receivers. [0003] like figure 1 As shown, in the existing radio frequency receiver, the radio frequency modulation signal is generally received into the radio frequency signal channel through the antenna 100 . The received RF radio frequency signal is amplified by the low noise amplifier 200 (LNA) at the front end, and converted into an easy-to-handle IF intermediate frequency signal by the mixer 300 (Mixer). The intermediate frequency signal is input to the intermediate frequency filter 400 (IF Filter) for channel selection, and filters out the inte...

AI Technical Summary

Problems solved by technology

However, with the increasing integration of radio frequency chips, although this dual-channel radio frequency receiver has a simple structure, its disadvantages are also very obvious: it will lead to an increase in the area of ​​the chip, an increase in the current consumption of the chip, and the gap between the sub-modules inside the chip. The isolation is correspondingly worse

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