PHASE MODULATION SIGNAL GENERATION CIRCUIT AND DISPLACEMENT DETECTION DEVICE USING THE SAME

• Main Authors: IWANAGA NOBUAKI, KOMABA HIDEO, MIBU KATSUTOSHI
• Format: Patent
• Language: English; Japanese
• Published: 25.08.2016
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; TARIFF METERING APPARATUS; TESTING

PROBLEM TO BE SOLVED: To provide a phase modulation signal generation circuit (displacement detection device) in which the effect of a drift or arithmetic error arising from an analog multiplication process is avoided and circuit configuration is simplified.SOLUTION: A phase modulation signal generation circuit 3 has: a modulation signal generation circuit 31 for generating a square wave modulation signal RsinT; a signal generation circuit 32 for shifting the phase of the modulation signal RsinT by 90° and generating gain control signals GSTL, GCTL; a series circuit of an analog switch 33 and a differential amplifier 34 for generating a balanced modulation signal Bc(T); a series circuit of an analog switch 35 and a differential amplifier 36 for generating a balanced modulation signal Bs(T); an addition circuit 37 for adding two balanced modulation signals Bc(T) and Bs(T), preferably, for current addition; and a low-pass filter (LPF) 38 having a small amount of attenuation.SELECTED DRAWING: Figure 6 【課題】アナログ乗算処理に伴うドリフトや演算誤差の影響を避け、回路構成を簡単にした位相変調信号生成回路（変位量検出装置）を提供する。【解決手段】位相変調信号生成回路３は、矩形波の変調信号ＲｓｉｎＴを生成する変調信号生成回路３１、変調信号ＲｓｉｎＴを９０°移相し利得制御信号ＧＳＴＬ、ＧＣＴＬを生成する信号発生回路３２、平衡変調信号Ｂｃ（Ｔ）を生成するアナログスイッチ３３と差動増幅アンプ３４との直列回路、平衡変調信号Ｂｓ（Ｔ）を生成するアナログスイッチ３５と差動増幅アンプ３６との直列回路、２つの平衡変調信号Ｂｃ（Ｔ）とＢｓ（Ｔ）を、好ましくは、電流加算する加算回路３７、および、減衰量の小さなローパスフィルタ（ＬＰＦ）３８を有する。【選択図】図６