Short range induction field communication system

• US 4,061,972 A
• Filed: 10/20/1976
• Issued: 12/06/1977
• Est. Priority Date: 12/03/1973
• Status: Expired due to Term

• Current Assignee: Victor Robert Burgess
• Original Assignee: Victor Robert Burgess
• Inventors: Burgess, Victor Robert
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Masinick, Michael A.
• Application Number:
  US05/734,381
• Time in Patent Office: 412 Days
• Field of Search: 179/82, 179/1 VC, 325/16, 325/22, 325/57, 325/58, 325/144, 325/187
• 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 5/73 for taking measurements, e.g. using sensing coils

Abstract

A short range communication or signalling system uses induction field FM or PCM capture effect properties to transfer information to receivers located outside the aerial configuration of the transmitter. When used as a deaf aid, the receiver is equipped with a conventional hearing aid for use when the transmitter is silent. Switching of the transmitter and receiver from one mode to another is achieved manually or using a VOX system. Adjustable sensors of field strength may be provided in the receiver (a) to inhibit transmission when a nearby transmitter is already operating and (b) to reduce the effective range of the receiver.

Claims

1. An induction field communication system which utilizes a modulation format enabling selection between similar electromagnetic signals by capture effect, said system comprising:

a. transmitting means for transmitting signals in said format and including an induction field generating aerial and microphone circuit, said transmitting means being equipped with an audio automatic gain control in its microphone circuit, said transmitting means having first and second transmitting modes,

b. a signal receiver for receiving signals in said format and having an induction field receiving aerial, said receiver being sufficiently within the induction field directly generated by said field generating aerial to cause signals from said transmitting means to capture said receiver to the exclusion of other similar signals received by said receiving aerail, and

c. control means for switching the transmitting means from said first transmitting mode to said second transmitting mode, said second transmitting mode being effective to switch the receiver to a different receiving mode.

2. A system as defined in claim 1, in which said receiver includes a received signal field strength sensor, said sensor generating an inhibition signal when the field strength of the received signal exceeds a predetermined value, said inhibition signal being operative to maintain said transmitting means in a non-transmitting mode.

3. A system as defined in claim 1, in which said receiver includes an adjustable sensor of received signal field strength, said sensor generating a signal which maintains said receiver in said different receiving mode when the received signal field strength is less than a predetermined value.

4. A system as defined in claim 1, in which said control means is voice operated.

5. A system as defined in claim 1, in which said transmitting means transmits signals by induction and said receiver receives signals by induction.

6. A system as defined in claim 1, in which the control means is manually operated.

7. A system as defined in claim 6, in which the second transmitting mode is a transmission carrier frequency shifted from the normal transmission carrier frequency of the transmitting means.

8. A system as defined in claim 6, in which the second transmitting mode is a high frequency FM tone.

9. A system as defined in claim 6, in which the second transmitting mode is a non-transmitting mode.

10. A system as defined in claim 6, in which the receiver includes a microphone responsive to ambient sound and said different receiving mode is reception from said receiver microphone.