Title:
MULTI-CHANNEL DYNAMIC STRAIN MEASURING APPARATUS
Document Type and Number:
Japanese Patent JP3480143
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To convert an amplitude modulation signal into a DC signal without being affected by the nonlinear characteristics of demodulator and requiring any low-pass filter.
SOLUTION: When dynamic strain test is started for a sample, the inner resistance of a bridge circuit 1 varies depending on the content of test and an amplitude modulated reference carrier signal is outputted from the bridge circuit 1. An adder 4 operates the difference between the amplitude modulated signal from an amplifier 3 and the output signal from a multiplier 7. The difference is passed through a demodulator 5 and an integration circuit 6 which produces a DC signal responding to a physical quantity of the sample. The multiplier 7 produces a feedback signal for substantially nullifying the output from adder 4. Since feedback control is performed to constantly nullify the output from adder 4, the demodulator 5 demodulates a small signal close to zero level and thereby the signal can be demodulated within the linear range of demodulator 5.
Inventors:
Teruji Matsubara
Nao Yoshida
Nao Yoshida
Application Number:
JP23009295A
Publication Date:
December 15, 2003
Filing Date:
September 07, 1995
Export Citation:
Assignee:
SHIMADZU CORPORATION
International Classes:
G01B21/32; G01B7/16; G01L1/22; (IPC1-7): G01B7/16; G01L1/22
Domestic Patent References:
| JP5669504A | ||||
| JP57161604A | ||||
| JP4928052U | ||||
| JP386580Y1 |
Attorney, Agent or Firm:
Fuyuki Nagai
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