Communication system

• US 20040233043A1
• Filed: 11/13/2003
• Published: 11/25/2004
• Est. Priority Date: 05/23/2003
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takei, Ken, Kamahori, Masao, Yazawa, Yoshiaki, Yoshigi, Hiroshi, Ohkawa, Takehiro
• Application Number:
  US10/705,894
• Publication Number:
  US 20040233043A1
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs

Abstract

A communication system is provided which enhances communication stability, using chips on which function blocks are formed including sensor, chip ID, and radio transmission/reception functions. The sensor detects biological and chemical materials and physical and stoichiometric quantities such as temperature, pressure, and pH and the sensed results are transmitted to a reader by a radio frequency (RF) function. The chip with the sensor functions at a resonance frequency which is detected by the reader initially during a frequency sweep. No dedicated power source is essential to operate the chips, but instead the chips are triggered into transmitting by the radio frequency signals transmitted from the reader. The frequency and output of transmission from the reader to the chips are variable. Stable communication can be performed without being affected by variation in the chips characteristics depending on manufacturing quality.

Claims

1. A communication system comprising:

a plurality of chips, each including a sensor, a chip ID retaining circuit for retaining a chip ID number, and a first resonance circuit; and

a reader comprising a second resonance circuit configured for carrying out transmission and/or reception of data to or from said plurality of chips, a frequency conversion circuit, and a chip ID compare circuit for comparing said chip ID number of each said chip for a match;

wherein, based on said chip ID retaining circuit, said frequency conversion circuit is configured to adjust carriers to a resonance frequency which is optimum per said chip and which has been obtained by a frequency sweep beforehand, and said reader is configured to communicate with each of said chips at said resonance frequency.

2. The communication system according to claim 1 wherein said reader further comprises data storage for storing resonance frequency information which stores a list of correspondence between said chip ID number and said optimum resonance frequency.

3. The communication system according to claim 1, further comprising an external control device which connects to said reader, said external control device including data storage for storing resonance frequency information and which stores a list of correspondence between said chip ID number and said optimum resonance frequency.

4. The communication system according to claim 1, wherein said resonance frequency is determined separately for each of said chips by said first resonance circuit on each of said chips.

5. The communication system according to claim 1, wherein said resonance frequencies are determined separately for each of said chips owing to circumstances around each said chip.

6. The communication system according to claim 1, wherein each of said chips further comprises a radio frequency (RF) control unit which comprises a rectification circuit, demodulation circuit, and modulation circuit, a power supply control unit, a communication control circuit, and a signal processing circuit,

wherein said signal processing circuit is configured to digitize signals detected by said sensor;

said demodulation circuit is configured to compare said data received with said chip ID number retained by said chip ID retaining circuit and demodulate said data;

and wherein said modulation circuit is configured to modulate the digitized signals detected by said sensor; and

the modulated digital signals detected by said sensor are transmitted by radio frequency (RF) to said reader.

7. The communication system according to claim 1, wherein said sensor is configured to measure the quantity, temperature, or pressure of an object to detect.

8. The communication system according to claim 1, further comprising:

a transport mechanism comprising piping and containers, wherein said chips are installed in said transport mechanism and said reader is placed outside said transport mechanism.

9. The communication system according to claim 8, wherein said sensor is configured to detect the conditions of a liquid fluid present inside said transport mechanism.

10. The communication system according to claim 8, wherein said chips are configured to communicate with said reader and transmit said chip ID number and measurements detected by said sensor;

and said chip ID number is corresponded to position information for each of said chips.

11. The communication system according to claim 8, wherein sections of said piping where said chips are installed have lower conductivity than other sections.

12. The communication system which is applied to the transport mechanism according to claim 8, wherein sections of said piping where said chips are installed have through holes and cores are inserted in said through holes.

13. The communication system according to claim 8, wherein said chips are supplied with required electric power by radio frequency transmission from said reader.

14. The communication system which is applied to the transport mechanism according to claim 8, further comprising:

an external control device which is installed outside said transport mechanism,

a transceiver connected to said external control device,

a transceiver antenna connected to said transceiver, and a reader antenna connected to said reader,

wherein said reader is provided with an additional long-range communication function and communicates with said external control device via said reader antenna, said transceiver antenna, and said transceiver.

15. A communicating reader comprising a resonance circuit, an oscillator, and a radio frequency control unit which includes a frequency conversion circuit,

wherein said resonance circuit and said oscillator carries out signal transmission and reception for communication with chips and a frequency sweep for said chips;

and

said frequency conversion circuit is configured to convert a transmitting frequency to each of said chips to a resonance frequency for communication with each of said chips, based on said frequency sweep.

16. The communicating reader according to claim 15, further comprising a chip ID compare circuit which retains chip ID codes independently retained on said chips and compares said chip ID codes for a match.

17. The communicating reader according to claim 15, further comprising a mechanism for controlling the strength of signals to be transmitted to said chips, according to the strength of signals received from said chips.

18. A communication method comprising:

transmitting from a reader information containing a chip ID code while performing a frequency modulation;

detecting in a chip whether there is a match between said chip ID code transmitted from the reader and a chip ID number unique to said chip; and

transmitting from said chip a result of detecting said match signals detected by a sensor included on said chip to said reader,

wherein, in said detecting step, said chip compares both of said chip ID code and said chip ID number for a match during said frequency modulation.

19. The communication method according to claim 18, wherein said information transmitting step and said detecting step are repeated until a match between both of said ID codes is detected.

20. The communication method according to claim 18, wherein a plurality of chips are used and each of said chips detects whether there is a match between said chip ID code received from said reader and said chip ID number unique to each of said chips.