Transceiver, modulation integrated circuit, and RFID reader/writer

• US 20070096878A1
• Filed: 10/17/2006
• Published: 05/03/2007
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Yamasaki, Kazushi
• Granted Patent: US 7,822,388 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: H04B 1/40 Circuits

Abstract

In a transceiver that selectively transmits a modulated wave and a non-modulated wave to the outside, and receives a response signal from the outside, an S/N ratio during reception is improved. A transceiver, which selectively transmits a modulated wave and a non-modulated wave to the outside, and receives a response signal from the outside, includes an oscillator generating a predetermined carrier wave; a modulator modulating the carrier wave generated by the oscillator with a transmitted baseband signal to generate the modulated wave; a power amplifier amplifying the modulated wave being modulated by the modulator, or the non-modulated wave being not modulated by the modulator; and a circulator for sending output of the power amplifier to an antenna. When the non-modulated wave is transmitted from the antenna, switches are switched to a bypass circuit side such that the oscillator is directly connected to the power amplifier.

Claims

1. A transceiver, which selectively transmits a modulated wave and a non-modulated wave to the outside, and receives a response signal from the outside, comprising:

an oscillator generating a predetermined carrier wave,

a modulator modulating the carrier wave generated by the oscillator to generate a modulated wave,

a transmission unit transmitting the modulated wave being modulated by the modulator or a non-modulated wave being not modulated, and

a control unit for directly connecting the oscillator to the transmission unit while bypassing the modulator when the transmission unit transmits the non-modulated wave.

2. The transceiver according to claim 1, further comprising:

a bypass circuit for bypassing the modulator by directly connecting the oscillator to the transmission unit,

wherein when the transmission unit transmits the non-modulated wave, the control unit transmits the non-modulated wave to the transmission unit via the bypass circuit.

3. The transceiver according to claim 2, wherein

a switch for routing through one of the bypass circuit or the modulator is provided between the oscillator and the transmission unit, and

the control unit performs selection of whether the oscillator is connected to the modulator, or directly connected to the transmission unit, by controlling the switch,

so that one of the modulated wave or the non-modulated wave is transmitted from the transmission unit.

4. A transceiver, which selectively transmits a modulated wave and a non-modulated wave to the outside, and receives a response signal from the outside, comprising:

an oscillator generating a predetermined carrier wave,

a modulator being inputted with a baseband signal produced according to data, and modulating the carrier wave generated by the oscillator with the baseband signal to generate a modulated wave,

a transmission unit transmitting the modulated wave modulated by the modulator or a non-modulated wave, and

an interruption unit interrupting input of the baseband signal into the modulator when the transmission unit transmits the non-modulated wave.

5. The transceiver according to claim 4:

wherein the modulator includes a switch for making connection to one of the input terminal for inputting the baseband signal and a DC voltage source, and

the interruption unit interrupts input of the baseband signal into the modulator by connecting the switch to the DC voltage source.

6. A modulation integrated circuit, which selectively transmits a modulated wave and a non-modulated wave to the outside, comprising:

a carrier wave input terminal for inputting the carrier wave from the outside,

a modulator for modulating the carrier wave inputted from the carrier wave input terminal,

an output terminal for outputting the modulated wave modulated by the modulator, or the non-modulated wave, and

a connection unit connecting the carrier wave inputted from the carrier wave input terminal to the output terminal while passing through the modulator when the modulated wave is outputted, and directly connecting the carrier wave to the output terminal without passing through the modulator when the non-modulated wave is outputted, according to a switching signal from the outside.

8. An RFID reader/writer, comprising:

the integrated circuit according to claim 6.

7. A modulation integrated circuit, which selectively transmits a modulated wave and a non-modulated wave to the outside, comprising:

an input terminal being inputted with a baseband signal produced according to data from the outside,

a modulator being provided in a manner connectable to the input terminal, and modulating the carrier wave inputted from the outside with the baseband signal to generate the modulated wave,

an output terminal for outputting the modulated wave modulated by the modulator, or the non-modulated wave, and

an interruption unit interrupting connection of the modulator to the input terminal when the non-modulated wave is outputted from the output terminal, according to a switching signal from the outside.

9. An RFID reader/writer, comprising:

the integrated circuit according to claim 7.