Contactless apparatus and card-type device having clock rectifier that is independent of power rectifier and demodulator with RC time constant based on selectable resistor
An information processing apparatus receives a carrier wave modulated in accordance with information and extracts the information and power therefrom to execute a given process. A receiving circuit receives the carrier wave. A dc power generating circuit rectifies the carrier wave received by the receiving circuit to thereby generate dc power. A demodulation circuit is structurally independent of the dc power generating circuit, and retrieves the information modulated onto the carrier wave. An information processing circuit is supplied with the dc power as a power source, and processes the information retrieved by the demodulation circuit in a given manner. Since the demodulation circuit and the dc power generating circuit are structurally independent of each other, interference between elements included in these circuits can be eliminated and simple designing is enabled. In addition, power consumed in the apparatus can be reduced because of optimal designing.
1. An information processing apparatus receiving a carrier wave modulated in accordance with information and extracting the information and power from the carrier wave to thereby execute a predetermined process, said information processing apparatus comprising:
a receiving circuit receiving the carrier wave;
a dc power generating circuit rectifying the carrier wave received by the receiving circuit to thereby generate dc power;
a demodulation circuit, structurally independent of the dc power generating circuit, retrieving the information modulated onto the carrier wave, and wherein said demodulation circuit comprises a rectifying element, a plurality of resistors with different resistance valves and a capacitor for demodulation by envelope detection and the envelope detection is performed with a time constant determined by the capacitor and one of the resistors selected in accordance with the frequency of the carrier wave;
an information processing circuit, supplied with the dc power as a power source, processing the information retrieved by the demodulation circuit in a given manner; and
a clock signal generating circuit generating a clock from the carrier wave received by said receiving circuit, wherein said clock signal generating circuit is independent of said dc power generating circuit and said demodulation circuit, and wherein said clock signal generating circuit comprises:
a full-wave rectifying circuit fully rectifying the carrier wave;
a waveform shaping circuit shaping a waveform of a signal output by the full-wave rectifying circuit; and
a frequency dividing circuit dividing a frequency of a waveform-shaped signal from the waveform shaping circuit.
2. The information processing apparatus as claimed in claim 1 , wherein:
said demodulation circuit comprises a full-wave rectifying circuit for demodulation by envelope detection.
3. A card-type information processing device receiving a carrier wave modulated in accordance with information and extracting the information and power from the carrier wave to thereby execute a predetermined process, said card-type information processing device comprising:
a receiving circuit receiving the carrier wave;
a dc power generating circuit rectifying the carrier wave received by the receiving circuit to thereby generate dc power;
a demodulation circuit, structurally independent of the dc power generating circuit, retrieving the information modulated onto the carrier wave, and wherein said demodulation circuit comprises a rectifying element, a plurality of resistors with different resistance valves and a capacitor for demodulation by envelope detection and the envelope detection is performed with a time constant determined by the capacitor and one of the resistors selected in accordance with the frequency of the carrier wave;
an information processing circuit, supplied with the dc power as a power source, processing the information retrieved by the demodulation circuit in a given manner; and
a clock signal generating circuit generating a clock from the carrier wave received by said receiving circuit, wherein said clock signal generating circuit is independent of said dc power generating circuit and said demodulation circuit, and wherein said clock signal generating circuit comprises:
a full-wave rectifying circuit fully rectifying the carrier wave;
a waveform shaping circuit shaping a waveform of a signal output by the full-wave rectifying circuit; and
a frequency dividing circuit dividing a frequency of a waveform-shaped signal from the waveform shaping circuit.
4. The card-type information processing device as claimed in claim 3 , wherein:
said demodulation circuit comprises a full-wave rectifying circuit for demodulation by envelope detection.