44 results about "Narrowband speech" patented technology

A system and method are disclosed for extending the bandwidth of a narrowband signal such as a speech signal. The method applies a parametric approach to bandwidth extension but does not require training. The parametric representation relates to a discrete acoustic tube model (DATM). The method comprises computing narrowband linear predictive coefficients (LPCs) from a received narrowband speech signal, computing narrowband partial correlation coefficients (parcors) using recursion, computing Mnb area coefficients from the partial correlation coefficient, and extracting Mwb area coefficients using interpolation. Wideband parcors are computed from the Mwb area coefficients and wideband LPCs are computed from the wideband parcors. The method further comprises synthesizing a wideband signal using the wideband LPCs and a wideband excitation signal, highpass filtering the synthesized wideband signal to produce a highband signal, and combining the highband signal with the original narrowband signal to generate a wideband signal. In a preferred variation of the invention, the Mnb area coefficients are converted to log-area coefficients for the purpose of extracting, through shifted-interpolation, Mwb log-area coefficients. The Mwb log-area coefficients are then converted to Mwb area coefficients before generating the wideband parcors.

A system and method are disclosed for extending the bandwidth of a narrowband signal such as a speech signal. The method applies a parametric approach to bandwidth extension but does not require training. The parametric representation relates to a discrete acoustic tube model (DATM). The method comprises computing narrowband linear predictive coefficients (LPCs) from a received narrowband speech signal, computing narrowband partial correlation coefficients (parcors) using recursion, computing Mnb area coefficients from the partial correlation coefficient, and extracting Mwb area coefficients using interpolation. Wideband parcors are computed from the Mwb area coefficients and wideband LPCs are computed from the wideband parcors. The method further comprises synthesizing a wideband signal using the wideband LPCs and a wideband excitation signal, highpass filtering the synthesized wideband signal to produce a highband signal, and combining the highband signal with the original narrowband signal to generate a wideband signal. In a preferred variation of the invention, the Mnb area coefficients are converted to log-area coefficients for the purpose of extracting, through shifted-interpolation, Mwb log-area coefficients. The Mwb log-area coefficients are then converted to Mwb area coefficients before generating the wideband parcors.

A system extends the bandwidth of a narrowband speech signal into a wideband spectrum. The system includes a high-band generator that generates a high frequency spectrum based on a narrowband spectrum. A background noise generator generates a high frequency background noise spectrum based on a background noise within the narrowband spectrum. A summing circuit linked to the high-band generator and the background noise generator combines the high frequency spectrum and narrowband spectrum and the high frequency background noise spectrum.

A speech compression apparatus including: a first band-transform unit transforming a wideband speech signal to a narrowband low-band speech signal; a narrowband speech compressor compressing the narrowband low-band speech signal and outputting a result of the compressing as a low-band speech packet; a decompression unit decompressing the low-band speech packet and obtaining a decompressed wideband low-band speech signal; an error detection unit detecting an error signal that corresponds to a difference between the wideband speech signal and the decompressed wideband low-band speech signal; and a high-band speech compression unit compressing the error signal and a high-band speech signal of the wideband speech signal and outputting the result of the compressing as a high-band speech packet.

A method for compressing voice frequency of digital deaf-aid includes carrying out time frequency domain conversion by utilizing a windowing Fourier transform, using slope of signal to digital spectrum to judge energy distribution of voice signal and dynamically regulating voice spectrum, realizing low-pass filter by removing off high spectrum coefficient and compressing voice band by regulating spectrum envelope.

A system and method for speech signal enhancement upsamples a narrowband speech signal at a receiver to generate a wideband speech signal. The lower frequency range of the wideband speech signal is reproduced using the received narrowband speech signal. The received narrowband speech signal is analyzed to determine its formants and pitch information. The upper frequency range of the wideband speech signal is synthesized using information derived from the received narrowband speech signal.

The perceived quality of a narrowband speech signal truncated from a wideband speech signal is improved by generating in a third frequency band third speech components matching first speech components in a first frequency band of the narrowband signal, and generating in a fourth frequency band fourth speech components matching second speech components in a second frequency band of the narrowband signal. A first gain factor is applied to the third speech components to generate adjusted third speech components, and a second gain factor is applied to the fourth speech components to generate adjusted fourth speech components, the gain factors being selected such that the ratios of the average powers of the adjusted third and fourth speech components to the average power of the first speech components are predetermined values.

The disclosure relates to a communication terminal having a bandwidth expansion device for expanding the bandwidth of a narrowband voice signal, on a low-frequency and / or high-frequency side, by synthesizing at least one frequency band on the basis of the narrowband voice signal. A qualitatively satisfactory bandwidth expansion is thus performed using a plurality of net bit rates. The bandwidth expansion device is further connected to a memory containing a lookup table comprising at least one parameter value for the bandwidth expansion, for at least two net bit rates of the narrowband voice signal. A method for expanding a bandwidth of a narrowband voice signal having at least two net bit rates in a communication terminal is also disclosed herein.

An electronic communication system is set forth that includes the transmission of a narrowband speech signal corresponding to a narrowband version of speech utterances of a speaker as well as the transmission of speaker-dependent data. The speaker-dependent data may be used to correlate narrowband versions of the speech utterances of the speaker with corresponding wideband versions of the speech utterances of the speaker. Both the narrowband speech signal and the speaker-dependent data are received by a receiving party. A receiver at the receiving party uses the narrowband speech signal and the speaker-dependent data to generate a wideband speech signal corresponding to a wideband version of the speech utterances of the speaker.

A method for determining an upperband speech signal from a narrowband speech signal is disclosed. A list of narrowband line spectral frequencies (LSFs) is determined from the narrowband speech signal. A first pair of adjacent narrowband LSFs that have a lower difference between them than every other pair of adjacent narrowband LSFs in the list is determined. A first feature that is a mean of the first pair of adjacent narrowband LSFs is determined. Upperband LSFs are determined based on at least the first feature using codebook mapping.

The invention discloses an encrypted earphone, which comprises a sound receiving and transmitting module used for receiving and outputting voice; the key generation module is used for generating a key according to a key generation strategy; the voice encryption module is used for encrypting the audio signal; the voice decryption module is used for decrypting the encrypted audio signal; the communication transceiving module is used for transmitting and receiving voice data; the secret key generation module comprises a first secret key factor generation sub-module and is used for generating a binary code according to a password input by a user and taking the binary code as a first secret key factor; the second key factor generation submodule is used for generating a second key factor according to the multiple groups of massive random keys; and the key generation sub-module is used for performing exclusive-or operation on the key factor I and the key factor II to obtain a key. According to the invention, digital coding, encryption and modulation of a sound source are realized through combination of a narrowband voice coding technology and a general password technology, and the method is applied to an encryption earphone.

The invention relates to a broadband and narrow-band voice clarity improving device in a mobile communication field. A cut-off frequency of a wave filter is automatically set according to the sampling frequency of an input signal. Voice frame level detection is performed on an input signal through an input enveloping line detecting part and the detected level is supplied to a cut-off frequency prediction part. Voice frame level detection is performed on an output signal and the detected level is supplied to the cut-off frequency prediction part. The cut-off frequency prediction part acquires a difference between the level of an N-th voice frame which is received from the input enveloping line detecting part and the level of an (N-1)th voice frame that is received from the output enveloping line detecting part, and furthermore utilizes the difference for calculating the cut-off frequency of a consonant component of the input signal. An oblique wave filter performs filtering on the input signal according to the cut-off frequency which is calculated by the cut-off frequency prediction part, and performs selective amplifying on the component which is predicated as the consonant component of the input signal.

A method, device, system, and computer program product expand narrowband speech signals to wideband speech signals. The method includes determining signal type information from a signal, obtaining characteristics for forming an upper band signal using the determined signal type information, determining signal noise information, using the determined signal noise information to modify the obtained characteristics for forming the upper band signal, and forming the upper band signal using the modified characteristics.

The invention discloses a DECT base station communication method, device and system. The method includes: according to the communication connection request sent by the handle, judging whether the base station meets the broadband voice communication requirements of the handle, and returning communication response information; if the communication response information is a positive response, making the base station and the handle perform broadband voice communication, and if the communication response information is a negative response, enable the base station to perform narrowband voice communication with the handle. The invention can realize the broadband voice communication between the DECT base station and more than six handles.