PHASE MODULATION CIRCUIT

• Main Authors: OGASAWARA ISAMU, BUSHIDA KENICHI, MORI KANEO
• Format: Patent
• Language: English
• Published: 21.04.1995
• Edition: 6
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; MODULATION

PURPOSE:To simplify phase modulation by supplying an AC current to a ferro magnetic line, generating an induced AC voltage due to a change in magnetic flux between both ends of the line, detecting the voltage and superimposing an AC current onto the detected voltage thereby changing a magnetic field. CONSTITUTION:A basic circuit of the phase modulation circuit is constituted of a ferromagnetic line 2, an AC coupling capacitive element 4 with respect to an induced voltage, an AC power supply 6 and a signal power supply 6. A current from the AC power supply 6 is supplied to both ends of the thin and long ferromagnetic line 2, and simultaneously, a control signal, that is, a modulation signal is applied from the signal power supply 8 to the both ends of the thin and long ferromagnetic line 2 thereby extracting the induced voltage produced in the ferromagnetic line 2 via the capacitive element 4. When the frequency of the AC current in use is lower, since a voltage across the resistance of the ferromagnetic line 2 is increased more than the induced voltage, the voltage across the resistance of the ferromagnetic line 2 is cancelled by using a resistance bridge circuit (not shown) to extract the induced voltage only. Thus, the cost of the modulation circuit is reduced without use of any active element.