Apparatus and methods for finding and using available transmission frequencies

• US 7,512,380 B2
• Filed: 08/17/2001
• Issued: 03/31/2009
• Est. Priority Date: 08/17/2001
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: McGowan, Steven B.
• Primary Examiner(s): Tsang; Fan
• Assistant Examiner(s): Hashem; Lisa
• Application Number:
  US09/932,286
• Publication Number:
  US 20030036357A1
• Time in Patent Office: 2,783 Days
• Field of Search: 455/501, 455/440, 455/556, 455/41.2, 455/456.1, 455/455, 455/457, 455/179.1, 455/3.06, 455/63.1, 455/63.3, 455/67.13, 455/90.2, 455/452.1, 455/509
• US Class Current: 455/63.3
• CPC Class Codes: H03J 1/0066 with means for analysing the received signal strength H03J1/0083 takes precedence
• CPC Class Codes: H03J 1/0091 provided with means for scanning over a band of frequencies H03J1/0058 takes precedence
• CPC Class Codes: H04B 1/034 Portable transmitters
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones

Abstract

A low-power radio frequency (RF) transmitter includes circuitry for finding unused transmission frequencies on a frequency band, such as an FM broadcast band, and to use an available frequency to broadcast a low-power audio signal to a sound reproduction device. In one embodiment, the sound reproduction device forms part of an entertainment system such as a vehicular stereo, home stereo, boom box, or RF headset. In one embodiment, the transmitter is operatively part of a sound generation device capable of generating and/or reproducing music or sound, such as an MP3 player or other portable entertainment device, personal digital assistant, electronic musical instrument, electronic toy, wireless microphone, or the like. The sound generation device can use an RF receiver or a geoposition source to identify an available transmission frequency. Also described are a sound generation system, a computer-readable medium, and various methods, including methods for finding and using available transmission frequencies.

Claims

1. A sound generation device comprising:

an audio source to generate an audio signal;

a frequency modulation (FM) radio frequency (RF) transmitter, coupled to the audio source, to transmit an FM carrier signal modulated with the audio signal, the FM carrier signal having a specific carrier frequency within the range of 87.7 to 107.9 megahertz that does not interfere with transmission frequencies in a commercial FM broadcast band of 87.7 to 107.9 megahertz in a geographical region in which the sound generation device is currently located;

a channel locator controller to identify an available non-interfering carrier frequency, wherein the channel locator controller includes

an RF receiver, coupled to the RF transmitter, to receive FM signals having different carrier frequencies; and

a channel locator circuit, coupled to the RF receiver, to identify two or more bands of FM carrier frequencies below a minimum signal strength;

wherein the channel locator controller is configured to identify an available non-interfering carrier frequency from an evaluation of the two or more bands of FM carrier frequencies; and

an out-of-band transmitter to transmit a channel selection signal comprising the available non-interfering carrier frequency.

2. The sound generation device recited in claim 1, wherein the sound generation device further comprises:

a channel selection circuit, coupled to the RF transmitter, to select the available carrier frequency on which to transmit the FM carrier signal.

3. The sound generation device recited in claim 1, wherein the sound generation device comprises one of an MP3 (Motion Picture Experts Group, Audio Layer 3) player, a compact disk player, a mini-disk player, a micro-disk player, a digital music player, a digital video disk player, a cassette tape player, a radio, a cellular phone, a handheld computer, a portable computer, a television, a video player, a personal digital assistant, an electronic musical instrument, an electronic toy, and a wireless microphone.

4. The sound generation device recited in claim 1, wherein the channel locator controller identifies the available non-interfering carrier frequency by selecting a center frequency of a first band of FM carrier frequencies having at least a predetermined frequency width.

5. The sound generation device recited in claim 1, wherein the channel locator controller identifies the available non-interfering carrier frequency by selecting a center frequency of a widest identified band.

6. A portable electronic device comprising:

a geoposition source;

an audio source coupled with the geoposition source to generate an audio signal;

a frequency modulation (FM) radio frequency (RF) transmitter, coupled to the audio source, to transmit an FM carrier signal modulated with the audio signal; and

a channel locator controller to identify an available non-interfering carrier frequency for the FM carrier signal having a specific carrier frequency within the range of 87.7 to 107.9 megahertz that does not interfere with transmission frequencies in a commercial FM broadcast band of 87.7 to 107.9 megahertz in a geographical region in which the portable electronic device is currently located;

wherein the channel locator controller includes a stored program digital computer, the computer to store a database of two or more available non-interfering carrier frequencies arranged by geoposition;

wherein the geoposition source is coupled to the stored program digital computer to provide a geoposition to the stored program digital computer;

wherein the channel locator controller is configured to identify a selected non-interfering carrier frequency from two or more available non-interfering frequencies stored in the database based on an evaluation of the two or more available non-interfering frequencies; and

an out-of-band transmitter to transmit a channel selection signal comprising the selected non-interfering carrier frequency.

7. The device recited in claim 6, wherein the audio source comprises prerecorded audio source material.

8. The device recited in claim 6, wherein the audio source comprises a digital music player.