High density wireless system

• US 8,497,940 B2
• Filed: 11/14/2011
• Issued: 07/30/2013
• Est. Priority Date: 11/16/2010
• Status: Active Grant

• Current Assignee: Audio Technica U.S. Inc (Audio-Technica Corporation)
• Original Assignee: Audio Technica U.S. Inc (Audio-Technica Corporation)
• Inventors: Igarashi, Masahiko, Kikutani, Tadashi, Naito, Yoshihiko, Green, Bob
• Primary Examiner(s): Harold, Jefferey
• Assistant Examiner(s): SANDERS, JUSTIN B
• Application Number:
  US13/295,561
• Publication Number:
  US 20120120313A1
• Time in Patent Office: 624 Days
• Field of Search: 348/485
• US Class Current: 348/485
• CPC Class Codes: H04B 1/005 adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method and apparatus for communicating within a wireless microphone system having a plurality of audio channels. The method includes the steps of dividing a small block of radio frequency spectrum associated with a single television broadcast channel into a plurality of at least 20 contiguous subchannels that are also contiguous with the boundaries of the television broadcast channel where each of the subchannels is less than 75 kHz and transmitting an audio signal from a microphone transmitter on one the plurality of subchannels through a transmitter with a radio frequency isolator or other means for suppressing intermodulation energy coupled to an antenna, the radio frequency isolator having a bandwidth no larger than any one of the plurality of divided subchannels; and receiving the audio signal through a microphone receiver.

Claims

1. A method of communicating within a wireless microphone system having a plurality of audio channels comprising:

dividing a small block of radio frequency spectrum associated with a single television broadcast channel into a plurality of at least 20 contiguous subchannels that are also contiguous with the boundaries of the television broadcast channel where each of the subchannels is less than 75 kHz;

receiving a channel assignment for operation of a microphone transmitter on one of the plurality of at least 20 contiguous subchannels through a user interface of a microphone receiver from a user;

the microphone transmitter upon activation proceeding to a default frequency, receiving the channel assignment, tuning to the assigned channel and transmitting an audio signal on the assigned subchannel through a radio frequency isolator or other means for suppressing intermodulation energy coupled between a transmitter and an antenna of the microphone transmitter; and

receiving the audio signal through the microphone receiver.

2. The method as in claim 1 wherein a maximum frequency deviation further comprises 16.5 kHz.

3. The method as in claim 1 wherein the broadcast television channel further comprises a bandwidth of 6 mHz.

4. The method as in claim 1 further comprising a compander within the microphone transmitter compressing an analog signal received from a microphone.

5. The method as in claim 1 further comprising the microphone transmitter and microphone receiver transceiving the audio signal under a time division multiplex format.

6. The method as in claim 1 further comprising defining the receiver as a diversity receiver.

7. The method as in claim 6 further comprising filtering an input to the receiver with a filter having a passband of frequencies equal to the spectrum of the single television broadcast channel.

8. The method as in claim 7 wherein the filtering further comprises 17 dB at a bandwidth of the small block of radio frequency spectrum.

9. The method as in claim 6 further comprising filtering an input to the receiver with a plurality of filters, each filter having a passband equal to frequencies within non-overlapping portions of the small block of radio frequency spectrum.

10. The method as in claim 9 further comprising adjusting a filtering frequency of each of the plurality of filters to select different non-overlapping portions of the small block of radio frequency spectrum.

11. The method as in claim 6 further comprising filtering an input to the receiver with a filter having a passband of frequencies defined by the spectrum of the small block of radio frequency spectrum.

12. The method as in claim 11 further comprising a downconverter downconverting the passband frequencies of the small block of radio frequency spectrum to an intermediate frequency.

13. The method as in claim 11 further comprising a separate receiver separating each of the plurality of contiguous subchannels from the downconverted passband frequencies.

14. An apparatus for communicating within a wireless microphone system having a plurality of audio channels comprising:

a base station that divides a small block of radio frequency spectrum associated with a single television broadcast channel into a plurality of at least 20 contiguous subchannels that are also contiguous with the boundaries of the television broadcast channel where each of the subchannels is less than 75 kHz;

at least one wireless microphone that transmits an audio signal on one the plurality of subchannels through a transmitter with a radio frequency isolator or other means for suppressing intermodulation energy coupled to an antenna, the radio frequency isolator having a bandwidth no larger than any one of the plurality of divided subchannels; and

receiving the audio signal through a microphone receiver; and

a user interface of the base station that receives a channel assignment from a user of the base station for operation of the at least one wireless microphone on an assigned one of the plurality of at least 20 contiguous subchannels wherein the at least one wireless microphone upon activation sends a signal to the base station, receives the channel assignment, tunes to the assigned one channel and transmits the audio signal to the base station on the assigned at least one channel.

15. The apparatus as in claim 14 further comprising a pair of diversity receivers that receive signals from the wireless microphones.

16. The apparatus as in claim 15 further comprising a transmitter within at least one of the diversity receivers that transmits a synchronization signal to the at least one wireless microphone.

17. The apparatus as in claim 14 further comprising a multiplexer that selects one of the at least 20 contiguous subchannels based upon a system address of the at least one wireless microphone and routes an audio signal on the selected subchannel to one of a plurality of outputs of the base station based upon the system address.

18. An apparatus for communicating within a wireless microphone system having a plurality of audio channels comprising:

a base station, the base station including a pair of diversity receivers, a controller, a user interface and at least one designated channel receiver, the controller and pair of diversity receivers divides a small block of radio frequency spectrum associated with a single television broadcast channel into a plurality of at least 20 contiguous subchannels that are also contiguous with the boundaries of the television broadcast channel where each of the subchannels is less than 75 kHz, the diversity receivers select at least one of the at least 20 contiguous subchannels based upon a system address of a wireless microphone and a channel assignment received from a user of the wireless micro phone system through the user interface the wireless micro hone upon activation sends a signal to the base station, receives the channel assignment, tunes to the assigned subchannel and transmits an audio signal, the base station reduces the audio signal from the wireless microphone on the selected subchannel to baseband and route the audio signal to the at least one designated channel receiver, the designated channel receiver routing the audio signal to one of a plurality of outputs of the designated channel receiver based upon the system address and assigned subchannel of the wireless microphone.

19. The apparatus as in claim 18 wherein the user interface further comprises a user interface accessible through the at least one designated channel receiver, the user interface comprising user interface software from a non-transitory computer readable medium, the user interface allowing a user to assign the system address to the at least one wireless microphone.

20. The apparatus as in claim 19 wherein the user interface further comprises the user interface accessible through the at least one designated channel receiver, the user interface comprising user interface software from the non-transitory computer readable medium, the user interface allowing the user to assign one of the contiguous subchannels to the at least one wireless microphone based upon the system address.