Data carrier
First Claim
Patent Images
1. A data carrier comprising:
- a resonance circuit for receiving a PWM signal having different duty ratios corresponding to write data containing identification codes in a transmission mode and having a fixed duty ratio in a reception mode,a waveform shaping circuit for smoothing and waveform shaping a received output obtained at said resonance circuit,a shift register for circulating and holding data, to which a signal obtained from said waveform shaping circuit is supplied as a shift pulse,signal switching means for switching an input supplied to said shift register by an output of said shift register from the output of said shaping circuit to the output of the shift register, anda vibration absorbing circuit for controlling reverberations of said resonance circuit based on a signal read from said shift register when a signal of a fixed duty ratio is supplied in the reception mode.
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Abstract
A data carrier according to the present invention writes a signal of a duty ratio corresponding to write data from a resonance circuit at the time of writing data using a shift register as a memory, causes the shift register to store the data, and then holds the data as a circulation mode. Then, the data held in the shift register is externally read out based on identification codes. In this way, a data carrier of a small storage capacity is made with a relatively simple structure.
3 Citations
9 Claims
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1. A data carrier comprising:
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a resonance circuit for receiving a PWM signal having different duty ratios corresponding to write data containing identification codes in a transmission mode and having a fixed duty ratio in a reception mode, a waveform shaping circuit for smoothing and waveform shaping a received output obtained at said resonance circuit, a shift register for circulating and holding data, to which a signal obtained from said waveform shaping circuit is supplied as a shift pulse, signal switching means for switching an input supplied to said shift register by an output of said shift register from the output of said shaping circuit to the output of the shift register, and a vibration absorbing circuit for controlling reverberations of said resonance circuit based on a signal read from said shift register when a signal of a fixed duty ratio is supplied in the reception mode. - View Dependent Claims (2, 3, 4)
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5. A data carrier comprising:
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a resonance circuit for receiving a PWM signal having different duty ratios corresponding to write data containing a start bit in a transmission mode and having a fixed duty ratio in a reception mode, a waveform shaping circuit for smoothing and waveform shaping a received output obtained at said resonance circuit, a shift register for circulating and holding write data obtained from said waveform shaping circuit, to which a signal obtained from said waveform shaping circuit is supplied as a shift pulse, signal switching means for switching an input applied to said shift register by an output of said shift register from an output of said waveform shaping circuit to the output of shift register, a counter for counting the number of shift pulses to said shift register, read data selecting means for selecting a shaping pulse obtained from said waveform shaping circuit and the output of said shift register by the output of said counter, and a vibration absorbing circuit for controlling the reverberations of said resonance circuit based on a signal read out by said read data selecting means when a signal of a fixed duty ratio is supplied in the reception mode. - View Dependent Claims (6)
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7. A data carrier comprising:
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a resonance circuit for receiving a PWM signal having different duty ratios corresponding to write data containing a start bit or a clear command in a transmission mode and having a fixed duty ratio in a reception mode, a waveform shaping circuit for smoothing and waveform shaping a received output obtained at said resonance circuit, a shift register for circulating and holding write data obtained by said waveform shaping circuit, to which a signal obtained from said waveform shaping circuit is supplied as a shift pulse, signal switching means for switching an input supplied to said shift register by an output of said shift register from an output of said waveform shaping circuit to the output of the shift register, a clear signal detecting portion for detecting a clear command obtained by said waveform shaping circuit and resetting said shift register at the time of detection, and a vibration absorbing circuit for controlling the reverberations of said resonance circuit based on a signal read out from said shift register when a signal of a fixed duty ratio is supplied in the reception mode. - View Dependent Claims (8, 9)
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Specification