Modulation signal generation circuit, transmission/reception module, and radar device

A transmission/reception module that transmits and receives a frequency modulation wave, and outputs a beat signal from a mixed wave of a transmission wave and a reception wave, the transmission/reception module comprising:

• a modulation-signal generating circuit including:
• a temperature monitoring unit that detects an ambient temperature of the circuit,
• a voltage control oscillator including a first variable impedance circuit and a second variable impedance circuit that independently control oscillation frequency of the voltage control oscillator based on an input control voltage,
• a frequency-correction-voltage generating unit that outputs a voltage for compensating for a temperature drift of the oscillation frequency according to the ambient temperature, for the first variable impedance circuit, and
• a frequency-modulation-voltage generating unit that outputs a modulation voltage containing a temperature-independent constant direct-current component and a predetermined alternate-current component, for the second variable impedance circuit, under a temperature drift compensation condition set by the frequency-correction-voltage generating unit.

A radar device that transmits and receives a frequency modulation wave, and calculates a relative distance and a relative speed with respect to a target object by performing a signal processing of a beat signal from a mixed wave of a transmission wave and a reception wave, the radar device comprising:

• a modulation-signal generating circuit including:
• a temperature monitoring unit that detects an ambient temperature of the circuit,
• a voltage control oscillator including a first variable impedance circuit and a second variable impedance circuit that independently control oscillation frequency of the voltage control oscillator based on an input control voltage,
• a frequency-correction-voltage generating unit that outputs a voltage for compensating for a temperature drift of the oscillation frequency according to the ambient temperature, for the first variable impedance circuit, and
• a frequency-modulation-voltage generating unit that outputs a modulation voltage containing a temperature-independent constant direct-current component and a predetermined alternate-current component, for the second variable impedance circuit, under a temperature drift compensation condition set by the frequency-correction-voltage generating unit.

A circuit for generating a modulation signal, comprising:

• a temperature monitoring unit that detects an ambient temperature of the circuit;
• a voltage control oscillator including a first variable impedance circuit and a second variable impedance circuit that independently control oscillation frequency of the voltage control oscillator based on an input control voltage;
• a frequency-correction-voltage generating unit that outputs a voltage for compensating for a temperature drift of the oscillation frequency according to the ambient temperature, for the first variable impedance circuit;
• and
• a frequency-modulation-voltage generating unit that outputs a modulation voltage containing a temperature-independent constant direct-current component and a predetermined alternate-current component that is set in advance according to the ambient temperature for the second variable impedance circuit, under a temperature drift compensation condition set by the frequency-correction-voltage generating unit.