Title:
超音波流量計
Document Type and Number:
Japanese Patent JP4746203
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce current consumption by eliminating a long-time peak value hold circuit and simplify a digital circuit of a received wave detecting part. SOLUTION: The received wave detecting part is composed of an amplification degree variable amplifying part for amplifying signals from a receiver, a comparator having three reference voltage levels, a comparator for detecting zero crossing, and the like. When a third wave of the received wave after amplified exceeds reference voltages of 200 mA and 500 mV all at once as shown in Fig. (a), a received wave detection signal is outputted at a point of the zero crossing. The received wave detection signal is outputted at a point of the zero crossing when the third wave exceeds the reference voltage of 350 mV at the reception afterwards. When the third wave does not reach 350 mV, the received wave detection signal is not outputted. An appropriate value is selected by adjusting the amplification degree of the amplifying part.
Inventors:
Noriyuki Nabeshima
Application Number:
JP2001138028A
Publication Date:
August 10, 2011
Filing Date:
May 09, 2001
Export Citation:
Assignee:
Aichi Clock Electric Co., Ltd.
International Classes:
G01F1/66
Domestic Patent References:
| JP10142019A | ||||
| JP10332452A | ||||
| JP61059275A | ||||
| JP61008622A | ||||
| JP200213958A |
Attorney, Agent or Firm:
Hasegawa Yoshimichi