Other

Kazuo Tsubouchi

Toshiyuki Azuma

Jun Hozumi

A code division multiple access apparatus which is capable of high-speed synchronization, is simple in construction and, moreover, achieves reduced consumption of electric power during standby. When a specific pattern contained in a signal received by a receiving antenna is detected by a SAW matched filter, a correlation peak is output from the filter. A bit synchronization signal generating circuit detects the correlation peak thereof and generates a synchronization signal after a set time has elapsed from the detection of the correlation peak. An orthogonal PN code generator generates a predetermined orthogonal PN code in accordance with the synchronization signal. Further, a carrier generator generates a carrier in response to the output of the SAW matched filter. This generated carrier is modulated by the output of the orthogonal PN code generator. Then, the signal received by the receiving antenna is multiplied together with the modulation output by a multiplier, integrated by an integrator and returned to its original baseband data form.

Code division multiple access apparatus

A radio IC card system includes an IC card and a toll collector. When an automobile with the IC card passes by a tollgate, the toll collector installed in the tollgate transmits a first radio signal which is spread modulated using a pseudorandom noise (PN) code from an antenna. The first radio signal is received by the antenna of the IC card and is transmitted to a surface acoustic wave (SAW) correlator. The SAW correlator extracts a PN code included in the received signal, and outputs a peak signal. An accumulation circuit accumulates the peak signal. A threshold discharger is activated to switch on a relay switch when the output voltage of the accumulation circuit exceeds a constant value. Thereby, the voltage of a battery is supplied to a data communication unit. Then, the identification code of the IC card and a record of tollgates by which the automobile has passed are transmitted via radio signal to the toll collector.

Radio IC card system

A radio data transmitter includes radio switching circuit which is activated in response to first radio signal having a predetermined particular pattern, and a data transmitter unit. The data unit transmits a first radio signal include a carrier modulated by predetermined data from an antenna when supplied with power in accordance with the activation of the radio switching circuit, and subsequently disconnect the power supply. In addition, a radio data receiver includes switch-activation to circuit for transmitting the first radio signal having the predetermined particular pattern, a receiving circuit for receiving the second radio signal including the data from the data transmitter unit activated by the first radio signal having the predetermined particular pattern, and a storage device for storing data received by the receiving circuit.

Radio data transmitter and receiver

A radio switching apparatus is provided which is actuated upon reception of a radio signal and which is capable zero or near-zero standby electric power consumption. The radio switching apparatus includes a receiving antenna; a surface-acoustic-wave device to which a signal received by the antenna is fed and which extracts a specific pattern contained in the signal; a storing circuit for storing output electric power of the surface-acoustic-wave device; and a switch circuit which is turned on when the output voltage of the storing circuit exceeds a set value.

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Miyagi-ken, Japan

Toshiyuki Azuma