Transmitter

• US 20060132325A1
• Filed: 12/16/2005
• Published: 06/22/2006
• Est. Priority Date: 12/16/2004
• Status: Abandoned Application

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Fujii, Masaki, Yamashita, Shuji
• Application Number:
  US11/305,505
• Publication Number:
  US 20060132325A1
• Time in Patent Office: Days
• US Class Current: 340/825.690
• CPC Class Codes: B60C 23/0433 Radio signals

Abstract

A transmitter transmits a wireless signal such as a request signal for a smart entry system by modulating a rectangular carrier wave with a base band signal from an antenna. A control unit is adapted to change the duty ratio of the carrier wave so as to change the transmission output of the wireless signal and thus to change its reception range. The control unit may also serve to change the transmission output of the wireless signal by varying the driving voltage that is applied to the antenna.

Claims

1. A transmitter comprising an antenna and a control unit for causing to transmit from said antenna a wireless signal formed by modulating a rectangular carrier wave having a specified duty ratio with a base band signal, said control unit serving to change the duty ratio of said carrier wave to thereby change the transmission output of said wireless signal and to thereby change the reception range of said wireless signal within which said wireless signal can be received.

2. The transmitter of claim 1 wherein said control unit further serves to change the transmission output of said wireless signal by varying the voltage that is applied to said antenna.

3. The transmitter of claim 1 wherein said control unit further serves to change the frequency of said carrier wave for changing the reception range of said wireless signal.

4. The transmitter of claim 2 wherein said control unit further serves to change the frequency of said carrier wave for changing the reception range of said wireless signal.