Transmission and receiver system operating on multiple audio programs

Abstract

A receiver contains a demodulator system that can extract digital data from wireless radio frequency signal. The digital data contains two sets of compressed digital audio data corresponding to two audio programs. The receiver also contains two decompressors. If a user selects a first audio program, a first compressor is used to decompress a first set of compressed digital audio data. If a user selects a second audio program, a second decompressor is used to decompress a second set of compressed digital audio data. The wireless radio frequency signal can be transmitted using a transmitter.

I claim: 
     
       1. An apparatus for generating analog audio signal, comprising:
 a demodulator for retrieving digital data from wireless radio frequency signal, the digital data comprising a first set of compressed digital audio data associated with a first audio program and a second set of compressed digital audio data associated with a second audio program, the first set of compressed digital audio data having been compressed outside of the apparatus from a first set of digital audio data, the second set of compressed digital audio data having been compressed outside of the apparatus from a second set of digital audio data;   a first decompressor comprising a first digital audio decompression algorithm;   a second decompressor comprising a second digital audio decompression algorithm;   a user interface allowing a user to select the first or the second audio program; and   a control subsystem for applying the first decompressor to decompress the first set of compressed digital audio data if the user selects the first audio program and applying the second decompressor to decompress the second set of compressed digital audio data if the user selects the second audio program.   
     
     
       2. The apparatus of  claim 1  wherein at least one of the first and the second decompression algorithms comprises a motion picture experts group decompression algorithm. 
     
     
       3. The apparatus of  claim 1  wherein at least one of the first and the second decompression algorithms comprises a voice quality decompression algorithm. 
     
     
       4. The apparatus of  claim 1  wherein at least one of the first and the second sets of compressed digital audio data has a bit rate of less than 7 kilobits per second. 
     
     
       5. The apparatus of  claim 1  wherein the radio frequency signal comprises FM modulated radio frequency signal. 
     
     
       6. The apparatus of  claim 1  wherein at least the demodulator is powered by a battery of an automobile. 
     
     
       7. The apparatus of  claim 1  wherein one of the first and the second sets of compressed digital audio data has been compressed using a parametric compression algorithm. 
     
     
       8. The apparatus of  claim 7  wherein another of the first and the second sets of compressed digital audio data has been compressed using a motion picture experts group compression algorithm. 
     
     
       9. The apparatus of  claim 1  wherein the first decompressor and the second decompressor are software modules in a ROM. 
     
     
       10. The apparatus of  claim 1  wherein the digital data comprises a command instructing the apparatus to perform a task. 
     
     
       11. An apparatus for sending wireless radio frequency signal to a receiving device, the apparatus comprising a wireless transmitter for transmitting the wireless radio frequency signal modulated by a stream of digital data, the stream of digital data comprising a first set of compressed digital audio data associated with a first audio program and a second set of compressed digital audio data associated with a second audio program, the first set of compressed digital audio data having been compressed outside of the receiving device using a first digital audio compression algorithm and the second set of compressed digital audio data having been compressed outside of the receiving device using a second digital audio compression algorithm. 
     
     
       12. The apparatus of  claim 11  wherein the first compression algorithm comprises a motion picture experts group compression algorithm. 
     
     
       13. The apparatus of  claim 11  wherein the second compression algorithm comprises a voice quality compression algorithm. 
     
     
       14. The apparatus of  claim 13  wherein the second set of compressed digital audio data has a bit rate of less than 7 kilobits per second. 
     
     
       15. The apparatus of  claim 11  wherein the radio frequency signal comprises FM modulated radio frequency signal. 
     
     
       16. The apparatus of  claim 11  wherein the digital data comprises a command instructing the receiving device to perform a task. 
     
     
       17. The apparatus of  claim 11  wherein one of the first and the second sets of compressed digital audio data has been compressed using a parametric compression algorithm and another of the first and the second sets of compressed digital audio data has been compressed using a motion picture experts group compression algorithm. 
     
     
       18. An apparatus for generating analog audio signal, comprising:
 a demodulator for retrieving digital data from wireless radio frequency signal, the digital data comprising a first set of compressed digital audio data associated with a first audio program and a second set of compressed digital audio data associated with a second audio program the first set of compressed digital audio data having been compressed outside of the apparatus from a first set of digital audio data, the second set of compressed digital audio data having been compressed outside of the apparatus from a second set of digital audio data;   a first decompressor comprising a first digital audio decompression algorithm;   a second decompressor comprising a second digital audio decompression algorithm;   a memory system for storing the first set of compressed digital audio data retrieved from the demodulator and not the second set of compressed digital audio data retrieved from the demodulator;   user interface allowing a user to select the first or the second audio program; and   a control subsystem for applying the second decompressor to decompress the second set of compressed digital audio data if the user selects the second audio program and for retrieving the first set of compressed digital audio data from the memory system and delivering to the first decompressor when the user selects the first audio program.   
     
     
       19. The apparatus of  claim 18  wherein at least one of the first and the second decompression algorithms comprises a voice quality decompression algorithm. 
     
     
       20. The apparatus of  claim 18  wherein one of the first and the second sets of compressed digital audio data has been compressed using a parametric compression algorithm. 
     
     
       21. The apparatus of  claim 20  wherein another of the first and the second sets of compressed digital audio data has been compressed using a motion picture experts group compression algorithm. 
     
     
       22. The apparatus of  claim 18  wherein:
 the digital data comprises a third set of compressed digital audio data associated with a third audio program, 
 the memory system further for storing the third set of compressed digital audio data, 
 the user interface comprises a first button to select one of the first and the third audio programs and a second button to select the second audio program, and 
 the control subsystem further for retrieving the third set of compressed digital audio data from the memory system and delivering to the first decompressor when the user selects the third audio program. 
 
     
     
       23. The apparatus of  claim 18  wherein the user interface allows the user to turn off power to at least a portion of the apparatus, and wherein the memory system stores the first set of compressed digital audio data even after the user activates the user interface to turn off the power. 
     
     
       24. The apparatus of  claim 18  wherein the first decompressor and the second decompressor are software modules in a ROM. 
     
     
       25. The apparatus of  claim 8  wherein the digital data comprises a command instructing the apparatus to perform a task. 
     
     
       26. A method for an apparatus to process digital audio data, comprising:
 demodulating wireless radio frequency signals transmitted by a first remote station to generate a plurality of sets of compressed digital audio data, at least one other set of compressed digital audio data and a command instructing the apparatus to switch to a second remote station, the command being transmitted without responding to an input by a user of the apparatus, the plurality of sets of compressed digital audio data and the at least one other set of compressed digital audio data being compressed outside of the apparatus;   storing the plurality of sets of compressed digital audio data in a memory of the apparatus but not the at least one other set of compressed digital audio data;   allowing the user to select at least one of the plurality of sets of compressed digital audio data stored in the memory;   if the user selects one set of the plurality of sets of compressed digital audio:
 retrieving from the memory at least a portion of the selected set of compressed digital audio data; 
 decompressing the retrieved portion of the selected set of compressed digital audio data using a first digital audio decompression algorithm to generate a first set of decompressed digital audio data; and 
 processing the first set of decompressed digital audio data to generate a first analog audio signal; 
   allowing the user to select the at least one other set of compressed digital audio data that is not stored in the memory;   if the user selects the at least one other set of compressed digital audio data:
 decompressing at least a portion of the at least one other set of compressed digital audio data using a second digital audio decompression algorithm to generate a second set of decompressed digital audio data; and 
 processing the second set of decompressed digital audio data to generate a second analog audio signal; and 
   responsive to the command: demodulating wireless radio frequency signals transmitted by the second remote station to generate an additional set of compressed digital audio data, the additional set of compressed digital audio data being compressed outside of the apparatus and can be decompressed by the apparatus using one of the first and the second digital audio decompression algorithms.    
     
     
       27. The method of claim 26 wherein at least one of the first and the second digital audio decompression algorithms comprises a motion picture experts group decompression algorithm.  
     
     
       28. The method of claim 26 wherein at least one of the first and the second digital audio decompression algorithms comprises a voice quality decompression algorithm.  
     
     
       29. The method of claim 26 wherein at least one of the first and the second digital audio decompression algorithms is software module in a ROM.  
     
     
       30. The method of claim 26 wherein the memory continues to store the plurality of sets of compressed digital audio data after at least a portion of the apparatus is not powered.  
     
     
       31. The method of claim 26 further comprising:
 storing the additional set of compressed digital audio data in the memory;   allowing the user to select the additional set of compressed digital audio data in the memory; and   if the user selects the additional set of compressed digital audio data:
 retrieving from the memory at least a portion of the additional set of compressed digital audio data; and 
 decompressing the retrieved portion of the additional set of compressed digital audio data using the first digital audio decompression algorithm.  
   
     
     
       32. An apparatus comprising:
 a demodulator for demodulating wireless radio frequency signals transmitted by a first remote station to generate a plurality of sets of compressed digital audio data, at least one other set of compressed digital audio data and a command instructing the apparatus to switch to a second remote station, the command being transmitted without responding to an input by a user of the apparatus, the plurality of sets of compressed digital audio data and the at least one other set of compressed digital audio data being compressed outside of the apparatus;   a first decompressor comprising a first digital audio decompression algorithm;   a second decompressor comprising a second digital audio decompression algorithm;   memory for storing the plurality of sets of compressed digital audio data generated by the demodulator but not the at least one other set of compressed digital audio data generated by the demodulator;   a user interface allowing the user to select at least one set of the plurality of sets of compressed digital audio data in the memory;   a control subsystem for retrieving at least a portion of the selected set of compressed digital audio data from the memory and delivering to the first decompressor after selection by the user;   the user interface also allowing the user to select the at least one other set of compressed digital audio data;   the control subsystem also for delivering at least a portion of the at least one other set of compressed digital audio data to the second decompressor after selection by the user; and   responsive to the command, the demodulator also demodulates wireless radio frequency signals transmitted by the second remote station to generate an additional set of compressed digital audio data, the additional set of compressed digital audio data being compressed outside of the apparatus and can be decompressed by the apparatus using one of the first and the second decompressors.    
     
     
       33. The apparatus of claim 32 wherein at least one of the first and the second digital audio decompression algorithms comprises a motion picture experts group decompression algorithm.  
     
     
       34. The apparatus of claim 32 wherein at least one of the first and the second digital audio decompression algorithms comprises a voice quality decompression algorithm.  
     
     
       35. The apparatus of claim 32 wherein at least one of the first and the second decompressors comprises software module in a ROM.  
     
     
       36. The apparatus of claim 32 wherein the user interface allows the user to turn off power to at least a portion of the apparatus, and wherein the memory stores the plurality of sets of compressed digital audio data even after the user uses the user interface to turn off the power. 
     
     
       37. The apparatus of claim 32 wherein the memory also stores the additional set of compressed digital audio data, the user interface also allows the user to select the additional set of compressed digital audio data in the memory, and the control subsystem also retrieves at least a portion of the additional set of compressed digital audio data from the memory and delivers to the first decompressor after selection by the user.