Local oscillator signal generating circuit applied to radio frequency transceiver

Abstract

The invention discloses a local oscillator signal generating circuit applied to a radio frequency transceiver. The local oscillator signal generating circuit comprises a voltage-controlled oscillator,a clock adjusting circuit, a frequency mixing circuit and a quadrature frequency divider, the voltage-controlled oscillator outputs a clock signal with the frequency of 4 / 3 LO; the clock adjusting circuit receives a clock signal with the frequency of 4 / 3 LO and adjusts the clock signal into a clock signal with the frequency of 2 / 3 LO; the frequency mixing circuit receives the clock signal with the 4 / 3 LO frequency and the clock signal with the 2 / 3LO frequency, and mixes the clock signal with the 4 / 3 LO frequency and the clock signal with the 2 / 3 LO frequency to obtain a clock signal with double LO frequency; the quadrature frequency divider receives a clock signal with double LO frequency and performs quadrature frequency division on the clock signal to obtain a quadrature local oscillator signal. The oscillation frequency of the voltage-controlled oscillator is four thirds of the LO frequency, a local oscillation signal of the radio frequency transceiver is generated in a frequency mixing mode, the influence of the traction effect can be effectively eliminated, and the stability and the phase noise performance of the LO signal are greatly improved.

Description

technical field [0001] The invention relates to a local oscillator signal generating circuit applied to a radio frequency transceiver, belonging to the technical field of radio frequency integrated circuits. Background technique [0002] With the rapid development of mobile communication, radar, space technology and test and measurement technology, higher and higher requirements are placed on radio frequency transceivers. Small size, high index and low power consumption are the development direction of today's RF transceiver technology. Corresponding to highly integrated single-chip RF transceivers, direct conversion architectures are often used; although direct conversion architectures bring advantages such as high integration, low power consumption, and large signal bandwidth, they also have some disadvantages of their own, such as: transmission frequency and The local oscillator (Local Oscillator, LO for short) frequency is the same, the voltage controlled oscillator (Vo...

AI Technical Summary

Problems solved by technology

Corresponding to highly integrated single-chip RF transceivers, direct conversion architectures are often used; although direct conversion architectures bring advantages such as high integration, low power consumption, and large signal bandwidth, they also have some disadvantages of their own, such as: transmission frequency and The local oscillator (Local Oscillator, LO for short) frequency is the same, the voltage controlled oscillator (Voltage Controlled Oscillator, VCO for short) oscillation frequency of the phase-locked loop is taken at the LO frequency or the double frequency of LO, and the transmitting power amplifier will pass the fundamental wave or the secondary Harmonics cause frequency pull to the VCO, this frequency pull effect will seriously affect the stability of the LO signal, leading to the deterioration of the phase noise

Images