42 results about "Frequency compression" patented technology

A system and method are provided for improving the quality and intelligibility of speech signals. The system and method apply frequency compression to the higher frequency components of speech signals while leaving lower frequency components substantially unchanged. This preserves higher frequency information related to consonants which is typically lost to filtering and bandpass constraints. This information is preserved without significantly altering the fundamental pitch of the speech signal so that when the speech signal is reproduced its overall tone qualities are preserved. The system and method further apply frequency expansion to speech signals. Like the compression, only the upper frequencies of a received speech signal are expanded. When the frequency expansion is applied to a speech signal that has been compressed according to the invention, the speech signal is substantially returned to its pre-compressed state. However, frequency compression according to the invention provides improved intelligibility even when the speech signal is not subsequently re-expanded. Likewise, speech signals may be expanded even though the original signal was not compressed, without significant degradation of the speech signal quality. Thus, a transmitter may include the system for applying high frequency compression without regard to whether a receiver will be capable of re-expanding the signal. Likewise, a receiver may expand a received speech signal without regard to whether the signal was previously compressed.

The method involves providing the audio signal into several frequency channels (31,32). The frequency associated with the fundamental frequency, in the frequency channel (32) is estimated as harmonic (20,30). The harmonics of the audio signal is moved or mapped from a frequency channel (31) in frequency channel (32). An independent claim is included for device for frequency compression of audio signal.

A method and system has been developed and demonstrated which provides real-time frequency translation, frequency compression, and user selectable response time for non-deterministic signals. This method and system provides for the real-time separation and isolation of theoretically an infinite amount of frequencies present in an incoming non-deterministic signal. The bandwidth of the filter for the separated frequencies is user selectable and provides varying rise times for the individual frequencies. The linear frequency shifting property of the algorithm creates bandwidth compression opportunities while signals are present in a channel for transmission.

A communications system is configured to reduce the risk of feedback artifacts and contains a telephone device and a listening device. Accordingly, the communication system is thus provided, in which the signal processing in the telephone device is tuned to the listening device and the listening device is configured to process the voice and data signal inversely to the signal processing. Before the acoustic signal is transmitted from the telephone to the listening device, a frequency compression can thus be carried out, and in the listening device an inverse frequency compression can be carried out. This reduces feedback artifacts.