Frequency circuit, radio frequency receiver and radio receiving-transmitting machine

Abstract

A frequency conversion circuit of the present invention includes: (i) a first mixer for mixing the radio frequency signal having a frequency fRF with a first oscillation signal having a frequency fLO1 so that the radio frequency signal is downconverted into an intermediate frequency signal; and (ii) a second mixer for mixing the intermediate frequency signal sent from the first mixer with two local oscillation signals so that the intermediate frequency signal is downconverted into two base-band signals having different phases. The second local oscillation signals have phases of 0° and 270°, respectively. These frequencies satisfies: <?in-line-formulae description="In-line Formulae" end="lead"?>fLO1=kxfRF(k>1) <?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>fLO2=fLO1 / m, (m>1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>k=m / (m-1).<?in-line-formulae description="In-line Formulae" end="tail"?> This arrangement ensures (i) a small frequency conversion circuit that can be mounted on an integrated circuit, (ii) a radio frequency receiver including the frequency conversion circuit, and (iii) a radio frequency transceiver including the radio frequency receiver.

Description

technical field [0001] The present invention relates to a radio frequency (RF) receiver and a radio frequency transceiver, and a frequency conversion circuit applicable to them, applicable to a wireless data communication system that can extract in-phase mobile phone and PHS (Personal Handyphone System; Personal Handyphone System) and other mobile communication systems, as well as wireless local area network (LAN) communication systems determined in accordance with IEEE 802.11x specifications. Background technique [0002] A typical existing RF transceiver is shown in Figure 10 . The radio frequency transceiver is composed of an antenna 1, a radio frequency preselection filter (bandpass filter (BPF)) 2, a duplex switch 3, and a receive path and a transmit path. The duplex switch 3 connects the antenna 1 to the path of the receiver 1004 or the path of the transmitter 1005 . The purpose of the RF transceiver is to convert baseband (BB) data to RF. In terms of signal energy...

AI Technical Summary

Problems solved by technology

If the 0° and 90° local oscillator signals are subjected to second-stage down-conversion as they are, the voltage vector when taken out as the baseband is rotated to the right (rotation direction from Q (90°) to I (0°)) , cannot normally demodulate

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