Binarization circuit, demodulation circuit, and tuner for vehicle

A demodulation circuit comprising:

• a frequency modulation (FM) demodulator configured to generate a frequency shift keying (FSK) demodulated signal by applying frequency-voltage conversion to a FSK signal;
• a first low pass filter (LPF) configured to generate an input voltage by limiting a frequency band of an output of the FM demodulator;
• a comparator configured to compare an input voltage with a reference voltage and output a signal in accordance with a differential voltage between the input voltage and the reference voltage;
• a first charging-discharging circuit configured to generate a first voltage by multiplying the differential voltage by a first charge-discharge factor;
• a second charging-discharging circuit configured to generate a second voltage by multiplying a difference between the differential voltage and a threshold voltage by a second charge-discharge factor greater than the first charge-discharge factor;
• and
• a control circuit configured to compare the differential voltage with the threshold voltage, and switch between turn-on and turn-off of the second charging-discharging circuit based on a difference between the differential voltage and the threshold voltage,
• wherein a sum of the reference voltage of a preceding clock and the first voltage of the preceding clock is supplied to the comparator when the second charging-discharging circuit is turned off, a sum of the reference voltage of the preceding clock, the first voltage of the preceding clock, and the second voltage of the preceding clock is supplied to the comparator when the second charging-discharging circuit is turned on.

Tuner for a vehicle, the tuner comprising:

• a comparator configured to compare an input voltage corresponding to a radio frequency signal sent from a remote key with a reference voltage and output a signal in accordance with a differential voltage between the input voltage and the reference voltage;
• a first charging-discharging circuit configured to generate a first voltage by multiplying the differential voltage by a first charge-discharge factor;
• a second charging-discharging circuit configured to generate a second voltage by multiplying a difference between the differential voltage and a threshold voltage by a second charge-discharge factor greater than the first charge-discharge factor;
• a control circuit configured to compare the differential voltage with the threshold voltage, and switch between turn-on and turn-off of the second charging-discharging circuit based on a difference between the differential voltage and the threshold voltage;
• and
• a door lock controller configured to control lock and unlock of a door of the vehicle based on the signal outputted from the comparator,
• wherein a sum of the reference voltage of a preceding clock and the first voltage of the preceding clock is supplied to the comparator when the second charging-discharging circuit is turned off, a sum of the reference voltage of the preceding clock, the first voltage of the preceding clock, and the second voltage of the preceding clock is supplied to the comparator when the second charging-discharging circuit is turned on.