ApplicationNo. 09428425 filed on 10/27/1999
US Classes:375/133, End-to-end transmission system375/135, Transmitter375/136, Receiver380/42, Data stream/substitution enciphering380/253, By signal having discrete frequency component725/18, By use of audio signal346/37, Radio receiver, tuning responsive704/227, Pretransmission455/68, With control signal360/60, Recording-or erasing-prevention348/484, Sound signal360/27, RECORDING OR REPRODUCING AN INFORMATION SIGNAL AND A CONTROL SIGNAL FOR CONTROLLING ELECTRONICS OF REPRODUCER725/20, By data encoded in video signal (e.g., VBI data)386/96, Audio signal369/124.09, Multiplexing or demultiplexing348/486, Including the use of a subcarrier375/216, APPARATUS CONVERTIBLE TO ANALOG382/115, Personnel identification (e.g., biometrics)382/232, IMAGE COMPRESSION OR CODING370/212, PULSE WIDTH (PULSE DURATION) MODULATION380/54, BY MODIFYING OPTICAL IMAGE (E.G., TRANSMISSIVE OVERLAY)704/500, AUDIO SIGNAL BANDWIDTH COMPRESSION OR EXPANSION375/240, BANDWIDTH REDUCTION OR EXPANSION704/200.1, Psychoacoustic380/238, Including frequency modification of audio signal or frequency shifting of audio carrier375/242, PULSE CODE MODULATION700/94, Digital audio data processing system375/130SPREAD SPECTRUM
ExaminersPrimary: Tran, Khai
Assistant: Lugo, David B.
Attorney, Agent or Firm
Foreign Patent References
International ClassesH04B 1/713
AbstractBlocks of audio are encoded based upon corresponding first and second frequencies. The first and second frequencies are hopped from block to block. An audio quality measure (AQM) is computed for each block of audio such that, if x out of y blocks of audio have an AQM greater than a first predetermined threshold, encoding is suspended. For example, x may be nine and y may be 16. Also, if a ratio of the energy in a front part of a block of audio to the energy in a rear part of the block of audio is greater than a second predetermined threshold, that block of audio is not encoded even though x out of y blocks of audio have an AQM greater than the first predetermined threshold. Multiple distributors of the audio may encode the audio with their corresponding identities using the above processes.