Inductively coupled wireless system and method

• US 6,424,820 B1
• Filed: 04/02/1999
• Issued: 07/23/2002
• Est. Priority Date: 04/02/1999
• Status: Expired due to Term

• Current Assignee: Vulcan Patents LLC
• Original Assignee: Interval Research Corporation
• Inventors: Burdick, Wayne A., Boyden, James H., Lynch, William C.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Nguyen, Simon
• Application Number:
  US09/285,511
• Time in Patent Office: 1,208 Days
• Field of Search: 455/41, 455/568, 455/569, 455/575, 455/66, 455/95, 455/129, 455/149, 455/151.2, 455/103, 455/132
• US Class Current: 455/41.1
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 7/0808 comparing all antennas before reception
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04H 20/48 for FM stereophonic broadcast systems
• CPC Class Codes: H04R 1/10 Earpieces; Attachments therefor ; Earphones; Monophonic headphones H04R1/28 takes precedence; stereophonic headphones H04R5/033
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

A short range inductively coupled wireless communication system employs analog frequency modulation of a high frequency carrier and magnetic coupling between a transmitting antenna and a receiving antenna. A transmitter coupled to the transmitting antenna modulates multiple high-fidelity analog audio signals and digital control messages onto separate high frequency (“HF”) carriers. The electric field portion of the transmitted electromagnetic field is substantially eliminated during transmission, while the magnetic field portion is substantially unaffected. The receiving antenna is coupled to a demodulator which reproduces the audio frequency signals and decodes control messages sent by the transmitter.

Claims

1. A wireless communication system, comprising:

a master control unit including a first control unit transmitter operating at a first carrier frequency and a control unit antenna system coupled to the first transmitter; and

a slave unit including a first slave unit receiver operating at the first carrier frequency and a first slave unit antenna system coupled to the first slave unit receiver, wherein the control unit antenna system and the first slave unit antenna system are coupled inductively; and

a second slave unit receiver operating at a second carrier frequency, wherein a spacing between the first carrier frequency and the second carrier frequency is approximately 200 kHz.

2. A wireless communication system, comprising:

a master control unit including a first control unit transmitter operating at a first carrier frequency and a control unit antenna system coupled to the first transmitter; and

a slave unit including a first slave unit receiver operating at the first carrier frequency and a first slave unit antenna system coupled to the first slave unit receiver, wherein the control unit antenna system and the first slave unit antenna system are coupled inductively;

wherein the first slave unit receiver includes a diversity logic, and the first slave unit antenna system includes a first diversity antenna and a second diversity antenna, wherein the diversity logic processes signals received from the first diversity antenna and the second diversity antenna and provides a signal to the remainder of the first slave unit receiver in accordance with a diversity scheme; and

a second slave unit receiver operating at a second carrier frequency, wherein a spacing between the first carrier frequency and the second carrier frequency is approximately 200 kHz.

3. A wireless communication system, comprising:

a master control unit including a first control unit transmitter operating at a first carrier frequency and a control unit antenna system coupled to the first transmitter; and

a slave unit including a first slave unit receiver operating at the first carrier frequency and a first slave unit antenna system coupled to the first slave unit receiver, wherein the control unit antenna system and the first slave unit antenna system are coupled inductively;

wherein the first slave unit receiver includes a diversity logic, and the first slave unit antenna system includes a first diversity antenna, a second diversity antenna, and a third diversity antenna, wherein the diversity logic processes signals received from the first diversity antenna, the second diversity antenna, and the third diversity antenna and provides a signal to the remainder of the first slave unit receiver in accordance with a diversity scheme; and

a second slave unit receiver operating at a second carrier frequency, wherein a spacing between the first carrier frequency and the second carrier frequency is approximately 200 kHz.

4. The wireless communication system of claim 3, wherein the diversity scheme selects the signal received from the first diversity antenna, the second diversity antenna, and the third diversity antenna that has the higher received signal strength indication (RSSI).

5. The wireless communication system of claim 3, wherein the diversity scheme processes the signals received from the first diversity antenna, the second diversity antenna, and the third diversity antenna and combines them in accordance with a predetermined weighting scheme.

6. The wireless communication system of claim 3, wherein the first diversity antenna, the second diversity antenna, and the third diversity antenna are oriented orthogonally to each other.