Abstract: A frequency linearity measurement circuit configured to measure a frequency linearity of a frequency signal includes: a first measurement circuit having a counter, where the counter is controlled by a gate signal having a gate signal period, where the first measurement circuit is configured to generate a first estimate of an integer number of clock cycles of the frequency signal within a respective gate signal period of the gate signal; a second measurement circuit having a time-to-digital converter (TDC), where the TDC is controlled by the gate signal, and is configured to generate a second estimate of a fractional number of clock cycle of the frequency signal within the respective gate signal period of the gate signal; and a reference measurement circuit configured to generate a third estimate of an expected number of clock cycles within the respective gate signal period of the gate signal.

Abstract: A frequency linearity measurement circuit configured to measure a frequency linearity of a frequency signal includes: a first measurement circuit configured to generate a first estimate of an integer number of clock cycles of the frequency signal within a respective gate signal period of a gate signal; a second measurement circuit comprising a time-to-digital converter (TDC) configured to generate a second estimate of a fractional number of clock cycle of the frequency signal within the respective gate signal period; a reference measurement circuit configured to generate a third estimate of an expected number of clock cycles within the respective gate signal period; and a closed-loop frequency tracking circuit configured to track a frequency error between an expected frequency and a measured frequency, where the expected frequency and the measured frequency are determined based on the third estimate and on a sum of the first estimate and the second estimate, respectively.

Abstract: A hand dryer includes improved electronic features and internal and external sensors. The improved hand dryer provides useful sensors for public restrooms. In that regard, air quality sensors, smoke detectors and ozone sensors provided by the hand dryer are particularly useful. A portable sensor device has electronic features and internal and external sensors. The portable sensor can be used by a traveler to make a traveler aware of the contents of the air they will be breathing in a hotel room. The portable sensor has sensors providing other valuable information to the traveler and can monitor the security of the room when the traveler is absent.

Abstract: A method for defining an index of a match between a content of two audio sources, comprising: sampling audio from a first source and a second source generating a first and second set of samples; selecting a sequential number of samples N belonging to the first set of samples and N samples belonging to the second set; transferring the first and second sequences of N samples to the frequency domain, generating a first and second sequences of N/2 frequency intervals; for the first sequence, calculating the sign of the derivative; for the second sequence, calculating the sign and the absolute value of the derivative, and a total sum of the absolute values of the derivative and a partial sum of the absolute values of the derivative; the ratio between the partial sum and the total sum being an index of the match of the audio sources.

Abstract: An audio tagging method adapted to insert, in audio generated by an audio source and represented in the frequency domain, an identification code which comprises a predefined number of bits, associating with each bit of the code a corresponding frequency interval and applying a bandpass filter centered on each of the frequency intervals associated with one of the bits of the code, such that: if the bit has the value 1, the value of the corresponding frequency interval is amplified; if the bit has the value 0, the value of the corresponding frequency interval is attenuated.

Abstract: A method for defining an index of a match between a content of two audio sources, comprising: sampling audio from a first source and a second source generating a first and second set of samples; selecting a sequential number of samples N belonging to the first set of samples and N samples belonging to the second set; transferring the first and second sequences of N samples to the frequency domain, generating a first and second sequences of N/2 frequency intervals; for the first sequence, calculating the sign of the derivative; for the second sequence, calculating the sign and the absolute value of the derivative, and a total sum of the absolute values of the derivative and a partial sum of the absolute values of the derivative; the ratio between the partial sum and the total sum being an index of the match of the audio sources.