Panasonic Corporation

Yong Wang

Masahiko Hashimoto

Takehiko Suginouchi

An ultrasonic measuring method includes: (A) receiving a coded spread spectrum ultrasonic signal in at least two receivers, and generating at least two received signals; (B) performing an quadrature detection on the received signals using the carrier frequency, and producing I and Q components of the received signals; (C) performing phase difference processing on the I and Q components with a coding period synchronized with that of the carrier frequency, and obtaining I' and Q&#x2032; components from which a phase shift caused by a Doppler shift has been canceled; (D) despreading the I&#x2032; and Q&#x2032; components signals using different codes at time intervals synchronized with the carrier frequency, and obtaining despread I&#x2033; and Q&#x2033; components; (E) computing the amplitude and phase information based on the I&#x2033; and Q&#x2033; components; and (F) calculating the propagation distance and/or orientation of the ultrasonic wave based on the amplitude and phase information.

Ultrasonic measuring method and ultrasonic measuring apparatus

An ultrasonic measurement method, including: receiving a plurality of ultrasonic waves that have been spectrum-spread with different codes by first and second wave-receivers; de-spreading the first and second receive signals respectively with a selected code and a non-selected code; obtaining an amplitude ratio between the produced selected de-spread signal and the non-selected de-spread signal; determining a threshold value based on the amplitude ratio; extracting a signal having an amplitude greater than or equal to the threshold value from the non-selected de-spread signal to thereby produce an interfering signal; spreading the interfering signal with a corresponding non-selected code and then removing the interfering signal from the first and second receive signals to thereby produce first and second receive signals from which the interfering signal has been removed; de-spreading the first and second receive signals from which the interfering signal has been removed each with the selected code to thereby obtain first and second de-spread signals from which the interfering signal has been removed; and calculating the propagation distance and the propagation direction of the selected ultrasonic wave based on points in time at which the first and second de-spread signals arrive at the first and second wave-receivers.

Ultrasonic measuring device and ultrasonic measuring method

An ultrasonic measuring method includes the steps of: receiving ultrasonic waves, which have been transmitted by a spread spectrum technique using mutually different codes, at first and second receivers, thereby generating first and second received signals, respectively; generating interference signals, of which the amplitudes are equal to or greater than respective threshold values, from the first and second received signals that have been despread with a code that has been used to spread any of the ultrasonic waves other than a desired one; removing the spread interference signals from the first and second received signals; calculating maximum correlation values between the first and second despread received signals for the respective threshold values; selecting one of the threshold values, at which the greatest one of the maximum correlation values has been obtained, as a threshold value for canceling interference; and calculating the propagation distance or propagation azimuth of the desired ultrasonic wave by the amount of time it has taken for the first and second received signals to arrive.

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Hyogo, Japan

Yong Wang