Methods and digital circuits providing frequency correction to frequency synthesizers are disclosed. An FLL digital circuit is provided that is configured to handle a reference frequency that is dynamic and ranges over a multi-decade range of frequencies. The FLL circuit includes a digital frequency iteration engine that allows for detection of disappearance of a reference frequency. When the digital frequency iteration engine detects that the reference frequency signal is not available, the oscillator generated frequency is not corrected, and the last value of the oscillator generated frequency is held until the reference frequency signal becomes available again. This FLL circuit is also preceded by a low-pass filter which is dynamically tuned to the frequency to which the FLL locks, eliminating harmonic components in the original signal which might otherwise cause errors in frequency estimation.

According to this disclosure, a method of synthesizing an audio stream sample using a processor is provided. The method comprises: generating a set of unnormalized log probabilities using a neural network, each unnormalized log probability associated with a possible value for the audio stream sample, sampling a Gumbel distribution for each of the unnormalized log probabilities, adding the samples from the Gumbel distribution to each of the respective unnormalized log probabilities to generate a set of modified log probabilities, each modified log probability associated with a possible value for the audio stream sample, and selecting the possible value of the audio stream sample associated with the largest modified log probability from the set of modified log probabilities as the audio stream sample.

A method comprising determining an envelope of an audio file based on a double-windowing analysis of the audio file.

A method comprising determining an envelope of an audio file based on a double-windowing analysis of the audio file.

A method for following a musical score in real time. At least one sound emitted by a performer is recorded. At least one chromatic vector is estimated. The chromatic vector is compared with theoretical chromatic vectors of the musical score. A transition between the chromatic vector and a previous chromatic vector with theoretical transitions of the musical score is compared. A work position of the performer depending on a previous work position is estimated from the comparison of the chromatic vector and the comparison of the transition. The recording is carried out for a suitable period depending on the ratio between a period of the transition and a reference period.

Methods and digital circuits providing frequency correction to frequency synthesizers are disclosed. An FLL digital circuit is provided that is configured to handle a reference frequency that is dynamic and ranges over a multi-decade range of frequencies. The FLL circuit includes a digital frequency iteration engine that allows for detection of disappearance of a reference frequency. When the digital frequency iteration engine detects that the reference frequency signal is not available, the oscillator generated frequency is not corrected, and the last value of the oscillator generated frequency is held until the reference frequency signal becomes available again. This FLL circuit is also preceded by a low-pass filter which is dynamically tuned to the frequency to which the FLL locks, eliminating harmonic components in the original signal which might otherwise cause errors in frequency estimation.

A method for following a musical score in real time. At least one sound emitted by a performer is recorded. At least one chromatic vector is estimated. The chromatic vector is compared with theoretical chromatic vectors of the musical score. A transition between the chromatic vector and a previous chromatic vector with theoretical transitions of the musical score is compared. A work position of the performer depending on a previous work position is estimated from the comparison of the chromatic vector and the comparison of the transition. The recording is carried out for a suitable period depending on the ratio between a period of the transition and a reference period.