Frequency synthesizer and multi-band radio apparatus using said frequency synthesizer
The frequency synthesizer comprises an HF synthesizer (11) for generating a first reference frequency signal having a variable frequency in a highfrequency band as a unit synthesizer, an LF synthesizer (12) for generating a second reference frequency signal in a low-frequency band as another unit synthesizer, and an arithmetic circuit including a mixer (13) for receiving the first and second reference frequency signals, a divider (14) for receiving the second reference frequency signal, a mixer (15) for receiving the first reference frequency signal and an output signal from the divider (14), a divider (16) for receiving an output signal from the mixer (14), a divider (17) for receiving an output signal from the mixer (15) and capable of switching a division ratio, and a switch (18) for switching and outputting output signals from the dividers (16, 17), wherein an output signal of the switch (18) is outputted as a first local signal, and an output signal from the divider (17) is outputted as a second local signal.