Infrared wireless headset system

• US 6,421,426 B1
• Filed: 08/15/1997
• Issued: 07/16/2002
• Est. Priority Date: 08/15/1997
• Status: Expired due to Fees

• Current Assignee: GN Netcom/Unex Inc.
• Original Assignee: GN Netcom/Unex Inc.
• Inventors: Lucey, Robert E.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): PERSINO, RAYMOND B
• Application Number:
  US08/911,225
• Time in Patent Office: 1,796 Days
• Field of Search: 379/56.3, 379/101, 455/462, 455/550, 455/575, 455/403, 455/568
• US Class Current: 379/56.3
• CPC Class Codes: H04B 10/1143 Bidirectional transmission
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04M 1/05 specially adapted for use on head, throat or breast
• CPC Class Codes: H04M 1/6033 for providing handsfree use or a loudspeaker mode in telephone sets arrangements for preventing acoustic echo H04M9/08
• CPC Class Codes: H04M 1/737 Characterised by transmission of electromagnetic waves other than radio waves, e.g. infrared waves

Abstract

A full duplex infrared communication system suitable for use in connection with a telephone system is disclosed. The communication system includes a base station and a remote wireless set. High quality audio is provided through use of an FM sinusoidal current driven signal transmission between the base station and the remote wireless set. Further, transmission is made over bands which do not harmonically overlap. For example, the base station may transmit at 250-430 1 KHz and the remote wireless set may transmit at 1.45-1.63 MHz. Further, adverse effects of cross-talk and signal reflection are reduced by using transmission carrier signals for the base station and the remote wireless set having different wavelengths. For example, the base station may use LEDs which emit signals at a wavelength of 940 nm while the remote wireless set may use LEDs which emit signals at a wavelength of 880 nm. LEDs with slow turn-on and turn-off times, e.g., approximately 1 microsecond, are used in the Base TX to minimize harmonic radiation and Base RX desensitization. The remote TX LEDs are current driven, and have much faster turn-on and turn-off times than the Base TX LEDs, however its radiated fundamental and harmonics are much higher in frequency than the remote RX frequency and do not effect it during normal operating conditions. Further, the system does not require optical gain (lens, parabolic reflectors) and is omnidirectional.

Claims

1. A full duplex wireless communication system for use in connection with a telephone system, comprising:

a first transceiver with a first transmit circuit and a first receive circuit, said first transceiver connected to the telephone system; and

a second transceiver with a second transmit circuit and a second receive circuit, said second transceiver being remote from said first transceiver,

wherein said first and second transmit circuits transmit frequency modulated signals and said first and second receive circuits receive said frequency modulated signals from said second and first transmit circuits, respectively, such that audio signals from the telephone system are;

a) received in said first transceiver, b) converted to frequency modulated signals having a first current driven signal in a first frequency and a first carrier signal in a first wavelength, c) transmitted to said second transceiver, d) received by wavelength tuned infrared sensors in said second transceiver, e) converted in a first mixer back to audio signals, and f) presented to a user of said second transceiver, and further wherein audio signals from the user of the second transceiver are;

a) converted to frequency modulated signals having a second current driven signal in a second frequency and a second carrier signal in a second wavelength, b) transmitted to said first transceiver, c) received by wavelength tuned sensors in said first transceiver, d) converted in a second mixer to audio signals and e) transmitted to the telephone system.

2. The communication system of claim 1 wherein the frequency modulated signals travel only within line of sight of the first and second transceivers.

3. The communication system of claim 2 wherein the frequency modulated signals are in the infrared spectrum.

4. The communication system of claim 3 wherein the infrared signals are transmitted directly between the first and second transceivers.

5. The communication system of claim 3 wherein the infrared signals are transmitted indirectly between the first and second transceivers by reflecting the signals upon other objects.

6. The communication system of claim 1 wherein selectivity in the second transceiver allows adjacent channels to be employed to allow greater than two transceivers to be independently utilized within a confined area.

7. The communication system of claim 1 wherein tone control signals directed from the second transceiver to the first transceiver cause at least one action selected from the group consisting of pick up, hang up, and operator flash.

8. The communication system of claim 1 wherein said first transmit circuit transmits in a first frequency band and said second transmit circuit transmit in a second frequency band, said first and second bands being non-overlapping.

9. The communication system of claim 8 wherein said first and second bands do not include overlapping harmonics.

10. The communication system of claim 9 wherein said first band is 250-430 Khz and said second band is 1.45-1.63 Mhz.

11. The communication system of claim 1 wherein said first transmit circuit and said second receive circuit are operative at said first wavelength, and said second transmit circuit and said first receive circuit are operative at said second wavelength, said first and second wavelengths being non-overlapping.

12. The communication system of claim 11 wherein said first wavelength is 940 nm and said second wavelength is 880 nm.

13. The communication circuit of claim 12 wherein said first and second transmit circuits include LEDs and said first and second receive circuits include tuned PIN diodes.

14. The communication circuit of claim 13 wherein lenses are employed to concentrate signals emitted by the LEDs.

15. The communication circuit of claim 13 wherein LED reflectors are employed to extend the range of the signals.

16. The communication system of claim 1 wherein said first transceiver is operational to turn OFF and to turn ON in response to tone control signals from said second transceiver.

17. The communication system of claim 1 wherein said second transceiver includes a battery from which said second transceiver is powered, and said communication system further includes a charging cavity operative to charge said battery, said second transceiver being operative to turn OFF in response to being placed in said charging cavity.

18. The communication system of claim 1 wherein said second transceiver includes a low battery indicator circuit which provides a signal indicative of a low battery condition to a user of said second transceiver.

19. The communication system of claim 1 wherein said second transceiver transmits signals with light emitting diodes (LEDs).

20. An improved method for transmitting audio signals between a telephone system and a remote wireless system including the steps of:

receiving, in a base station, a first audio signal originating from the telephone system;

transmitting the first audio signal from said base station to a remote wireless set by driving a first infrared generating component with a first frequency modulated current signal corresponding to said first audio signal, thereby producing a first frequency modulated signal;

receiving, in the remote wireless set, said first frequency modulated signal with a first wavelength tuned infrared sensitive component and converting in a first mixer said first frequency modulated signal back to generate said first audio signal therefrom;

receiving, in the remote set, a second audio signal originating from a user;

transmitting said second audio signal from the remote set to the base station by driving a second infrared generating component with a second frequency modulated current signal corresponding to the second audio signal, thereby producing a second frequency modulated signal;

receiving, in the base station, said second frequency modulated signal with a second wavelength tuned infrared sensitive component and converting in a second mixer said second frequency modulated signal back to generate said second audio signal therefrom;

relaying said second audio signal to the telephone system;

driving the first infrared generating component in a first frequency band and driving said second infrared generating component in a second frequency band, said first and second frequency bands being distinct from one another such that said first and second frequency bands do not overlap harmonically; and

transmitting said first frequency modulated signal at a first wavelength and transmitting said second frequency modulated signal at a second wavelength, said first and second wavelengths being distinct from one another.

21. A communication system for use in connection with a telephone system, the communication system comprising:

a base station connected directly to a telephone line of the telephone system, said base station including,

a circuit capable of sensing an incoming telephone call on said telephone line,

a circuit which converts audio signals to first frequency modulated signals within a first frequency band,

infrared LEDs for transmitting said first frequency modulated signals at a first wavelength,

wavelength tuned PIN diodes for receiving second frequency modulated signals at a second wavelengths, and

a first mixer for converting said second frequency modulated signals in a second frequency band back to audio signals; and

a remote wireless set including,

wavelength tuned PIN diodes for receiving said first frequency modulated signals at said first wavelength,

a second mixer for converting said first frequency modulated signals in said first frequency band back to audio signals,

a speaker for conveying audio signals to a user,

a microphone for sensing audio signals originating from a user of said remote wireless set,

a circuit for converting audio signals sensed by said microphone to second frequency modulated signals in said second frequency band, and

infrared LEDs for transmitting said second frequency modulated signals at said second wavelength,

wherein said first and second frequency bands are distinct from one another and said first and second wavelengths are distinct from one another,

whereby the user of the remote wireless set can carry on a telephone conversation with a user of the telephone system via infrared frequency modulated signals.

22. The communication system of claim 21 wherein said base station transmits over a 250-430 Khz band and said remote wireless set transmits over a 1.45-1.63 Mhz band.

23. The communication system of claim 22 wherein base station LEDs transmit at a wavelength of 940 nm and said remote wireless set LEDs transmit at a wavelength of 880 nm.