RANGE MEASURING METHOD, RANGE MEASURING APPARATUS, NON-CONTACTED IC MEDIUM AND RANGE MEASURING SYSTEM

• US 20090195438A1
• Filed: 12/18/2008
• Published: 08/06/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: KAWAI, TAKEHIRO
• Granted Patent: US 8,149,155 B2
• Time in Patent Office: Days
• US Class Current: 342/127
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement

Abstract

A method of measuring a range from a reader unit to a non-contacted IC medium, includes: transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium; causing the non-contacted IC medium to perform modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency, and causing the non-contacted IC medium to respond to a response signal at the modulated frequency; causing the reader unit to receive the response signal to acquire a plurality of frequency components; calculating a phase difference between signals of at least two of the acquired plurality of frequency components; and measuring the range by using the phase difference.

Claims

1. A method of measuring a range from a reader unit to a non-contacted IC medium, the method comprising:

transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium;

causing the non-contacted IC medium to perform modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency, and causing the non-contacted IC medium to respond to a response signal at the modulated frequency;

causing the reader unit to receive the response signal to acquire a plurality of frequency components;

calculating a phase difference between signals of at least two of the acquired plurality of frequency components; and

measuring the range by using the phase difference.

2. The method according to claim 1, wherein phase shift keying is used for the modulation.

3. The method according to claim 1, wherein frequency shift keying is used for the modulation.

4. The method according to claim 1, wherein

the modulation is digital modulation, and

the plurality of frequency components are high frequency components generated in the digital modulation.

5. The method according to claim 1, wherein the response signal is separated into an upper side band and a lower side band in order to acquire the plurality of frequency components.

6. An apparatus, operable to measure a range from a reader unit to a non-contacted IC medium, the apparatus comprising:

a communication unit, transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium, and receiving a response signal from the non-contacted IC medium;

a frequency component acquiring unit, acquiring a plurality of frequency components from the response signal; and

a range measuring unit, calculating a phase difference between signals of at least two of the acquired plurality of frequency components, and measuring the range by using the phase difference.

7. A non-contact IC medium, comprising:

a communication unit, receiving an inquiry signal at a first frequency from a reader unit, and responding to a response signal to the reader unit; and

a modulation unit, performing modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency,

wherein the communication unit responds to the response signal at the modulated frequency.

8. A range measuring system, comprising:

a non-contacted IC medium; and

a range measuring apparatus, operable to measure a range from a reader unit to the non-contacted IC medium, the apparatus comprising;

a first communication unit, transmitting an inquiry signal at a first frequency from the reader unit to the non-contacted IC medium, and receiving a response signal from the non-contacted IC medium;

a frequency component acquiring unit, acquiring a plurality of frequency components from the response signal; and

a range measuring unit, calculating a phase difference between signals of at least two of the acquired plurality of frequency components, and measuring the range by using the phase difference, wherein

the non-contacted IC medium comprises;

a second communication unit, receiving the inquiry signal at the first frequency from the reader unit, and responding to the response signal to the reader unit; and

a modulation unit, performing modulation to modulate the first frequency by using a second frequency to obtain a modulated frequency, and

the second communication unit responds to the response signal at the modulated frequency.