US 2009/0015477 A1 · TRANSMITTING DEVICE

Abstract

The number of driving circuits in signal transmission using plural antennas can be reduced. When a first antenna is driven, a CPU makes an LF driving circuit to output driving current, and sets a first switch to ON while setting a second switch and a third switch to OFF. By setting the first switch to ON, a connector terminal and GND are connected. Therefore, a closed circuit containing the LF driving circuit and the first antenna is constructed, and the first antenna is driven, whereby the signal of LF waves is output. The second switch and the third switch are set to OFF, so that a closed circuit containing the LF driving circuit and a second antenna is not constructed, and also a closed circuit containing a third antenna is not constructed. The second antenna and the third antenna are not driven.

Claims2

Dependent claims

A transmitting device for transmitting a signal from a desired antenna out of plural antennas, comprising:

antenna driving means for supplying driving current to a desired antenna;
plural switches connecting the antenna driving means to each of the plural antennas;
and
control means for controlling the antenna driving means and outputting a control signal for controlling whether each of the switches is opened or closed, wherein the control means specifies an antenna to which the signal should be transmitted, and outputs a control signal for closing the specified switch out of the switches.

1 more element

Dependencies are inferred from the claim text.

Transmitting device

Life of this patent

Transmitting device

Life of this patent

Abstract

Claims2