APPARATUS AND METHOD FOR TRANSMITTING, RECEIVING PULSE SIGNAL

Japanese Patent JP3558491

B2

PROBLEM TO BE SOLVED: To improve detection accuracy by extending a time axis of a detected wave by a sample hold circuit, amplifying and digitally converting a signal and detecting as a detection time point when an amplitude of the signal reaches a threshold value of a constant ratio first.
SOLUTION: A detected signal from a receiving antenna 6 is held by a sample hold circuit 9 through a balance transformer 7 and a high frequency amplifier circuit 8 with a slightly longer cycle than a cycle of transmission trigger pulses. A time base of a signal waveform is extended. After the detected signal is amplified at a variable gain amplifier circuit 12 through a low bandpass filter circuit 10 and a low frequency amplifier circuit 11, the signal is supplied to a digital signal processor 1 through an A/D converter circuit 13. A maximal value appearing in the detected signal waveform first is detected. The variable gain amplifier circuit 12 is controlled so as to maintain the maximal value at a constant peak value. In this state, a time point when an amplitude of a part rising first of the detected signal waveform reaches a threshold value set to be approximately 3-4% of the peak value is detected as a detection time point.

Toshimitsu Nozu

JP14467197A

August 25, 2004

May 19, 1997

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Photoelectric Manufacturing Co., Ltd.

E02D1/02; G01N9/24; G01N22/00; G01N22/04; G01S13/88; G01V3/12; (IPC1-7): G01N22/04; G01N22/00; G01S13/88; G01V3/12

JP9089807A
JP50139664A
JP60009219A
JP2101291U
JP6201828A
JP63307340A
JP2196960A
JP2066484A
JP3225289A

Toshihiko Sakurai

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