Reception time determining apparatus and distance measuring apparatus using the same

A reception time determining apparatus which measures the reception time of a transmission signal from a transmitter,

• wherein said transmission signal is a signal which produces a demodulation signal in which a signal change portion is unevenly distributed on a time axis and the waveform thereof is continuous on the time axis,
• said apparatus comprising:
• a demodulation section which demodulates a reception signal and outputs said demodulation signal;
• a signal change portion detection section which detects said signal change portion contained in said demodulation signal which is output from said demodulation section, and outputs a signal change portion detection signal;
• and
• a first time measurement section which measures a reception time of said reception signal based on said signal change portion detection signal output from said signal change portion detection section,
• wherein said signal change portion detection section comprises a band pass filter configured to pass at least one portion of frequency components contained in said signal change portion and to inhibit frequency components comprising a main lobe of the power spectrum of said demodulation signal, and
• wherein said first time measurement section measures said reception time based on an output signal of said band pass filter.