Non-contact data recording medium

A non-contact data recording medium which has internal circuits and in which a power-supply voltage generated from a carrier wave transmitted from an external device is applied to the internal circuits, the carrier wave is demodulated, and data is transmitted, said medium comprising:

• first and second carrier-wave receiving means for receiving first and second carrier waves, respectively, which are shifted in phase with respect to each other;
• first and second power-supply means for rectifying the first and second carrier waves received by said first and second carrier-wave receiving means, thereby applying direct-current voltages to the internal circuits;
• constant-current means for adjusting current flowing to said first and second power supply means such that current flows in both said first and second power supply means;
• voltage-adjusting means for adjusting the direct-current voltages applied from said first and second power supply means to a voltage of a predetermined value;
• first and second wave-shaping means for shaping waveforms of the first and second carrier waves received by said first and second carrier-wave receiving means;
• and
• demodulating means for demodulating said first and second carrier waves having waveforms shaped by said first and second wave-shaping means, thereby generating a data signal.

A non-contact data recording medium which has internal circuits and in which a power-supply voltage generated from a carrier wave transmitted from an external device is applied to the internal circuits, the carrier wave is demodulated, and data is transmitted, said medium comprising:

• first and second coils for receiving first and second carrier waves from the external device, said first and second carrier waves being shifted in phase with respect to each other;
• a first rectifying circuit connected to said first coil for rectifying the first carrier wave to generate a first direct-current voltage;
• a second rectifying circuit connected to said second coil for rectifying the second carrier wave to generate a second direct-current voltage;
• a first constant current circuit provided in said first rectifying circuit for adjusting the current in said first rectifying circuit to a first constant current;
• a second constant current circuit provided in said second rectifying circuit for adjusting the current flowing in said second rectifying circuit to a second constant current;
• a voltage adjusting circuit for adjusting said first and second direct-current voltages generated by said first and second rectifying currents such that said first and second direct-current voltages have the same value, and for controlling said first and second constant current circuits to equalize said first and second constant currents flowing in said first and second rectifying circuits;
• a first wave shaping circuit for shaping the waveform of said first carrier wave received by said first coil;
• a second wave-shaping circuit for shaping the waveform of said second carrier wave received by said second coil;
• and
• demodulating means for demodulating said first and second carrier waves having waveforms shaped by said first and second wave-shaping means, thereby generating a data signal.