Phase modulating apparatus, communication device, mobile wireless unit, and phase modulating method

A phase modulation method that generates a phase modulation signal by performing phase modulation on a transmit signal, said phase modulation method comprising:

• a step of inputting a communication mode setting signal identifying one of a plurality of communication system modes and performing a comparative determination of a size relationship of a modulation bandwidth corresponding to said communication mode setting signal and a bandwidth of a phase locked loop circuit;
• a step of switching said phase locked loop circuit to 1-point modulation when said modulation bandwidth corresponding to said communication mode setting signal is narrowband compared with said bandwidth of said phase locked loop circuit, and switching said phase locked loop circuit to 2-point modulation when a modulation bandwidth corresponding to said communication mode setting signal is wideband compared with said a bandwidth of said phase locked loop circuit;
• and
• a step of, when said phase locked loop circuit is switched to 2-point modulation, changing a resonance frequency of a loop filter of that phase locked loop circuit and changing a bandwidth of said phase locked loop circuit in a wideband direction.

A phase modulation method that generates a phase modulation signal by performing phase modulation on a transmit signal, said phase modulation method comprising:

• a step of inputting a communication mode setting signal identifying one of a plurality of communication system modes and performing a comparative determination of a size relationship of a modulation bandwidth corresponding to said communication mode setting and a bandwidth of a phase locked loop circuit;
• a step of switching said phase locked loop circuit to 1-point modulation when a modulation bandwidth corresponding to said communication mode setting signal is narrowband compared with said bandwidth of said phase locked loop circuit, and switching said phase locked loop circuit to 2-point modulation when a modulation bandwidth corresponding to said communication mode setting signal is wideband compared with said bandwidth of said phase locked loop circuit;
• and
• a step of, when said phase locked loop circuit is switched to 2-point modulation, changing a reference frequency of that phase locked loop circuit and changing said bandwidth of said phase locked loop circuit in a wideband direction.