Radio switching apparatus

• US 5,905,449 A
• Filed: 03/06/1997
• Issued: 05/18/1999
• Est. Priority Date: 03/12/1996
• Status: Expired due to Term

• Current Assignee: Kazuo Tsubouchi
• Original Assignee: Kazuo Tsubouchi
• Inventors: Tsubouchi, Kazuo, Azuma, Toshiyuki, Hozumi, Jun
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): Dalencourt, Yves
• Application Number:
  US08/811,811
• Time in Patent Office: 803 Days
• Field of Search: 340/825.69, 340/825.31, 340/825.34, 340/825.72, 333/151, 333/154, 333/133, 333/193, 333/194, 333/195, 333/196, 455/78, 455/119
• US Class Current: 340/12.54
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

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.

Claims

1. A radio switching apparatus, comprising:

a receiving antenna;

a surface-acoustic-wave matched filter to which a signal received by said antenna is fed and which extracts a specific pattern contained in said signal;

a storing circuit for storing output electric power of said surface-acoustic-wave matched filter; and

a switch circuit which is turned on when the output voltage of said storing circuit exceeds a set value.

2. A radio switching apparatus according to claim 1, wherein said surface-acoustic-wave matched filter is formed of an Al₂ O₃ substrate, an AlN film formed on said Al₂ O₃ substrate, and an Al tapping pattern formed on said AlN film.

3. A radio switching apparatus according to claim 1, wherein said storing circuit includes an LC tank circuit, rectifying means for rectifying an output of said LC tank circuit, and a capacitor for storing the output of said rectifying means.

4. A radio switching apparatus according to claim 1, wherein said switch circuit includes a semiconductor switch which is turned on when the output voltage of said storing circuit exceeds a set value, a and switch means driven by the semiconductor switch.

5. A radio switching apparatus according to claim 1, wherein said switch circuit includes a light-emitting element which emits light when the output voltage of said storing circuit exceeds a set value, a semiconductor switch which is turned on upon receiving light from the light-emitting element, and switch means driven by the semiconductor switch.