Patent ID: 7349672

Claim:
A digital signal transceiver comprising: a frequency modulator for outputting a modulated signaling a transmitting mode, and for outputting a non-modulated signal in a receiving mode, said frequency modulator comprising: a variable frequency oscillator and a first frequency divider unit that switches between a modulating frequency divider and a non-modulating frequency divider, the non-modulating frequency divider receiving a signal output from the variable frequency oscillator and outputting a non-modulated signal, and the modulating frequency divider receiving the signal output from the variable frequency oscillator and a modulating signal and outputting the modulated signal; a power amplifier for receiving the modulated signal output from the frequency modulator; an antenna terminal arranged to be connected to an antenna; an antenna switch comprising a first branch port for receiving a signal output from the power amplifier, a common port connected to the antenna terminal, said common port being connected to the first branch port in the transmitting mode, and a second branch port connected to the common port in the receiving mode; a filter having an input port thereof connected to the second branch port of the antenna switch; a high-frequency amplifier having an input port thereof connected to an output port of the filter; and a mixer for mixing a signal output from the high-frequency amplifier with the signal output from the frequency modulator to output a signal including the signal from the high-frequency amplifier and the signal from the frequency modulator.