Demodulator and wireless receiver including the same

A demodulator, comprising:

• a phase difference signal generator that generates a first phase difference signal representing a phase difference between a digitally modulated digital modulation signal and an oscillation signal;
• a low-resolution A/D converter that performs analog-digital conversion of the first phase difference signal with a resolution lower than at least a resolution of a digital demodulation signal, which is a final output, to generate a second phase difference signal that is digital;
• a D/A converter that performs digital-analog conversion of the second phase difference signal to generate a third phase difference signal that is analog;
• a first control signal generator that subtracts the third phase difference signal from the first phase difference signal to generate a first control signal that is analog;
• a second control signal generator that generates, on a basis of a reference signal and the oscillation signal, a fourth phase difference signal that is digital and has a phase opposite to a phase of the first phase difference signal, and adds the second phase difference signal to the fourth phase difference signal to generate a second control signal that is digital and has a phase opposite to a phase of the first control signal;
• a frequency variable oscillator that generates the oscillation signal on a basis of the first control signal and the second control signal;
• and
• a digital demodulation signal generator that demodulates the digital modulation signal on a basis of the fourth phase difference signal.

A wireless receiver provided with a demodulator, the demodulator comprising:

• a phase difference signal generator that generates a first phase difference signal representing a phase difference between a digitally modulated digital modulation signal and an oscillation signal;
• a low-resolution A/D converter that performs analog-digital conversion of the first phase difference signal with a resolution lower than at least a resolution of a digital demodulation signal, which is a final output, to generate a second phase difference signal that is digital;
• a D/A converter that performs digital-analog conversion of the second phase difference signal to generate a third phase difference signal that is analog;
• a first control signal generator that subtracts the third phase difference signal from the first phase difference signal to generate a first control signal that is analog;
• a second control signal generator that generates, on a basis of a reference signal and the oscillation signal, a second control signal that is analog or digital and has a phase opposite to a phase of the first control signal;
• a frequency variable oscillator that generates the oscillation signal on a basis of the first control signal and the second control signal;
• and
• a digital demodulation signal generator that demodulates the digital modulation signal on a basis of the second control signal.

A wireless receiver provided with a demodulator, the demodulator comprising:

• a phase difference signal generator that generates a first phase difference signal representing a phase difference between a digitally modulated digital modulation signal and an oscillation signal;
• a low-resolution A/D converter that performs analog-digital conversion of the first phase difference signal with a resolution lower than at least a resolution of a digital demodulation signal, which is a final output, to generate a second phase difference signal that is digital;
• a D/A converter that performs digital-analog conversion of the second phase difference signal to generate a third phase difference signal that is analog;
• a first control signal generator that subtracts the third phase difference signal from the first phase difference signal to generate a first control signal that is analog;
• a second control signal generator that generates, on a basis of a reference signal and the oscillation signal, a fourth phase difference signal that is digital and has a phase opposite to a phase of the first phase difference signal, and adds the second phase difference signal to the fourth phase difference signal to generate a second control signal that is digital and has a phase opposite to a phase of the first control signal;
• a frequency variable oscillator that generates the oscillation signal on a basis of the first control signal and the second control signal;
• and
• a digital demodulation signal generator that demodulates the digital modulation signal on a basis of the fourth phase difference signal.