Noncontact communication medium, magnetic tape cartridge, magnetic tape drive, and noncontact communication system

A noncontact communication medium that performs communication, via a magnetic field provided from an external device, with the external device in a noncontact manner, the noncontact communication medium comprising:

• a resonance circuit configured to resonate using an induced current induced, with application of the magnetic field to an antenna coil, by the antenna coil to generate an alternating current voltage;
• and
• a control circuit,
• wherein the resonance circuit includes
• a variable condenser connected in parallel to the antenna coil, and
• a variable resistor connected in parallel to the antenna coil,
• the control circuit is configured to adjust capacitance of the variable condenser to cause the resonance circuit to resonate at a predetermined resonance frequency, and to adjust a resistance value of the variable resistor to adjust a Q value,
• the noncontact communication medium is configured to operate using power based on a direct current voltage obtained by rectifying the alternating current voltage, and
• the communication is communication using a signal corresponding to a waveform of the alternating current voltage.