Abstract: The present disclosure discloses an audio playback apparatus having noise-canceling mechanism that includes a sound receiving circuit, a storage circuit, a filter control circuit, a filter circuit and an audio playback circuit. The sound receiving circuit receives received audio signal including noise. The storage circuit stores filter parameters. The filter control circuit includes a noise estimation circuit, a noise distribution determination circuit and a parameter generation circuit. The noise estimation circuit receives the received audio signal and calculates a stationary noise power spectrum density of the noise such that the noise distribution determination circuit determines a noise spectrum distribution accordingly. The parameter generation circuit analyses the noise spectrum distribution and retrieves a group of selected filter parameters accordingly. The filter circuit filters the received sound signal according to the group of selected filter parameters to generate an anti-noise audio signal.

Abstract: An active noise cancellation (ANC) circuit includes: an audio generating circuit; an audio input unit for transmitting an audio to be broadcast or a sound testing signal as a first time domain signal; an audio receiver for receiving a background sound as a second time domain signal, wherein the background sound corresponds to the audio to be broadcasted or the sound testing signal; and a channel estimation unit, configured to receive the first time domain signal and the second time domain signal, perform time-frequency conversion upon the first time domain signal and the second time domain signal to obtain a first frequency domain signal and a second frequency domain signal respectively, and generate a frequency response according to the first frequency domain signal and the second frequency domain signal. The frequency response is for adjusting an active noise cancelling coefficient of the ANC circuit to improve a noise cancellation effect.

Abstract: The present invention discloses a direction-finding chip, a direction-finding method and a beacon. The direction-finding chip is applied to a beacon of a direction-finding system. The beacon includes multiple antennas and an inertial measurement unit (IMU). A mobile device can calculate angle information according to supplement provided by the beacon. The direction-finding chip includes a computation circuit and a radio frequency circuit. The computation circuit generates coordinate conversion information or a correction amount of the coordinate conversion information according to an acceleration and a magnetic field vector generated by the IMU. The coordinate conversion information or the correction amount can be used to compensate the angle information. The radio frequency circuit is coupled to the computation circuit and configured to transmit the supplement and the coordinate conversion information or the correction amount.

Abstract: The present disclosure discloses an audio playback apparatus having noise-canceling mechanism that includes a sound receiving circuit, a storage circuit, a filter control circuit, a filter circuit and an audio playback circuit. The sound receiving circuit receives received audio signal including noise. The storage circuit stores filter parameters. The filter control circuit includes a noise estimation circuit, a noise distribution determination circuit and a parameter generation circuit. The noise estimation circuit receives the received audio signal and calculates a stationary noise power spectrum density of the noise such that the noise distribution determination circuit determines a noise spectrum distribution accordingly. The parameter generation circuit analyses the noise spectrum distribution and retrieves a group of selected filter parameters accordingly. The filter circuit filters the received sound signal according to the group of selected filter parameters to generate an anti-noise audio signal.

Abstract: The present invention provides an audio adjustment method and associated audio adjustment device for active noise cancellation. The audio adjustment method includes: broadcasting a single tone having a frequency fk; generating M sets of filtering coefficients regarding the frequency fk, wherein each set of filtering coefficients within the M sets of filtering coefficients includes a combination of an amplitude and a phase, and the M sets of filtering coefficients are different from one another; determining an mth set of filtering coefficients from the M sets of filtering coefficients to minimize energy corresponding to the frequency fk; and adjusting the single tone with the mth set of filtering coefficients to obtain an adjusted single tone corresponding to the frequency fk.

Abstract: An active noise cancellation (ANC) circuit includes: an audio generating circuit; an audio input unit for transmitting an audio to be broadcast or a sound testing signal as a first time domain signal; an audio receiver for receiving a background sound as a second time domain signal, wherein the background sound corresponds to the audio to be broadcasted or the sound testing signal; and a channel estimation unit, configured to receive the first time domain signal and the second time domain signal, perform time-frequency conversion upon the first time domain signal and the second time domain signal to obtain a first frequency domain signal and a second frequency domain signal respectively, and generate a frequency response according to the first frequency domain signal and the second frequency domain signal. The frequency response is for adjusting an active noise cancelling coefficient of the ANC circuit to improve a noise cancellation effect.

Abstract: The present invention provides an audio adjustment method and associated audio adjustment device for active noise cancellation. The audio adjustment method includes: broadcasting a single tone having a frequency fk; generating M sets of filtering coefficients regarding the frequency fk, wherein each set of filtering coefficients within the M sets of filtering coefficients includes a combination of an amplitude and a phase, and the M sets of filtering coefficients are different from one another; determining an mth set of filtering coefficients from the M sets of filtering coefficients to minimize energy corresponding to the frequency fk; and adjusting the single tone with the mth set of filtering coefficients to obtain an adjusted single tone corresponding to the frequency fk.

Abstract: An audio playback device having a noise-cancelling mechanism is provided that includes an external sound-receiving circuit that receives external noise, a fixed-coefficient filtering circuit, an operation circuit, an audio playback circuit, an internal sound-receiving circuit and an adjusting circuit. The fixed-coefficient filtering circuit generates an inverted signal including a main and an auxiliary inverted components having the same amplitude and phases orthogonal to each other according to the external noise. The operation circuit multiplies the inverted signal by adjusting parameters to generate an adjusted inverted signal. The audio playback circuit receives and playbacks an audio signal and the adjusted inverted signal to generate a playback result. The internal sound-receiving circuit receives the playback result to generate a received sound signal.

Abstract: A gas cylinder lease system is disclosed, comprising one or more lease equipments and a cloud server equipment, wherein the inside of the lease equipment is installed with at least one placement rack area for accommodating the gas cylinder; accordingly, after any one of the lease equipments has been rented and at least one gas cylinder has been taken out, the renter may subsequently return the used gas cylinder to the lease main rack located at the same or different locations, with the use status of each placement rack area being uploaded to the cloud server equipment in real-time thereby monitoring the operation status of each lease equipment and executing corresponding replenishment and maintenance tasks in a timely fashion.

Abstract: The present invention discloses a direction-finding chip, a direction-finding method and a beacon. The direction-finding chip is applied to a beacon of a direction-finding system. The beacon includes multiple antennas and an inertial measurement unit (IMU). A mobile device can calculate angle information according to supplement provided by the beacon. The direction-finding chip includes a computation circuit and a radio frequency circuit. The computation circuit generates coordinate conversion information or a correction amount of the coordinate conversion information according to an acceleration and a magnetic field vector generated by the IMU. The coordinate conversion information or the correction amount can be used to compensate the angle information. The radio frequency circuit is coupled to the computation circuit and configured to transmit the supplement and the coordinate conversion information or the correction amount.

Abstract: A block code decoding method and device thereof are provided. The procedure of the bounded distance decoding is simplified and the number of correlation calculating is reduced via a set of pre-established XOR masks. The decoding method includes: picking up the source code part of the received message; executing a XOR calculating for the source code part with the XOR masks, and encoding the results thereof to produce a set of compared codes; executing a correlation calculating for the set of compared codes and the received message; and determining a compared code having the maximum correlation result as the decision.

Abstract: An apparatus for performing channel estimation includes a time-domain estimating circuit to perform a channel estimation on a time-domain received signal to output a time-domain estimated signal, a second frequency-domain converting circuit to convert the time-domain estimated signal into a frequency-domain estimated signal, an error computing circuit to produce an error signal based on the frequency-domain estimated signal and a frequency-domain received signal, and a compensation circuit to compensate the frequency-domain estimated signal using the error signal so as to produce a final channel estimation signal. The apparatus is located in a receiving device that includes a first frequency-domain converting circuit to convert the time-domain received signal into the frequency-domain received signal, and an equalizer to generate a frequency-domain recovered signal based on the frequency-domain received signal and the final channel estimation signal.

Abstract: An apparatus and an associated method for automatic gain control (AGC) are provided to improve the ability to lock effective signal power when interference exists, thereby upgrading the receiver performance of a communication system. The apparatus includes a variable-gain circuit for adjusting the power level of an input signal. The apparatus also includes a gain adjustment circuit and a target value adjustment circuit. The gain adjustment circuit is for adjusting the gain of the variable-gain circuit according to the adjusted input signal and a target value, while the target value adjustment is for dynamically adjusting the target value according to the strength of the adjusted input signal.

Abstract: The present invention discloses a decoding device. The decoding device includes a scaling unit for adjusting a received signal according to a scaling coefficient to generate a scaled signal; a quantizer coupled to the scaling unit for generating a quantized signal by quantizing the scaled signal; a soft decision decoder coupled to the quantizer for decoding the quantized signal to generate a decoded signal; and a scaling coefficient generating unit coupled to the scaling unit for generating the scaling coefficient according to a system information of the decoding device.

Abstract: A block code decoding method and device thereof are provided. The procedure of the bounded distance decoding is simplified and the number of correlation calculating is reduced via a set of pre-established XOR masks. The decoding method includes: picking up the source code part of the received message; executing a XOR calculating for the source code part with the XOR masks, and encoding the results thereof to produce a set of compared codes; executing a correlation calculating for the set of compared codes and the received message; and determining a compared code having the maximum correlation result as the decision.

Abstract: An apparatus for performing channel estimation includes a time-domain estimating circuit to perform a channel estimation on a time-domain received signal to output a time-domain estimated signal, a second frequency-domain converting circuit to convert the time-domain estimated signal into a frequency-domain estimated signal, an error computing circuit to produce an error signal based on the frequency-domain estimated signal and a frequency-domain received signal, and a compensation circuit to compensate the frequency-domain estimated signal using the error signal so as to produce a final channel estimation signal. The apparatus is located in a receiving device that includes a first frequency-domain converting circuit to convert the time-domain received signal into the frequency-domain received signal, and an equalizer to generate a frequency-domain recovered signal based on the frequency-domain received signal and the final channel estimation signal.

Abstract: A method for detecting inter-symbol interference (ISI) in an OFDM system includes the steps of computing a first correlation value representing the correlation between a plurality of first signals of a first symbol and a plurality of second signals of a second symbol previous to the first symbol, wherein the first and the second signals are both transmitted via the same sub-carriers; computing a second correlation value representing the correlation between the first signals and a plurality of third signals of a third symbol next to the first symbol, wherein the first and the third signals are both transmitted via the same sub-carriers; comparing the first correlation value with the second correlation value; and adjusting the timing of the boundary according to the comparison result.

Abstract: A method for detecting inter-carrier-symbol interference (ICSI) in an OFDM system includes the steps of computing a first correlation value representing the correlation between at least one of first signals of a first symbol and at least one of second signals of a second symbol previous to the first symbol, wherein the first signal is transmitted via a first sub-carrier and the second signal is transmitted via a second sub-carrier adjacent to the first sub-carrier; computing a second correlation value representing the correlation between the at least one first signal and at least one of third signals of a third symbol next to the first symbol, wherein the signal is transmitted via the first sub-carrier and the third signal is transmitted via the second sub-carrier; comparing the first correlation value with the second correlation value; and adjusting the timing of the boundary according to the comparison result.

Abstract: A boundary tracking method applied in an OFDM receiver includes generating a plurality of demodulated signal sets corresponding to part of sub-carriers of a packet according to different boundaries with different positions located at the packet, determining the most precise one of the boundaries according to a plurality of inter-symbol interference (ISI) values according to the demodulated signal sets, and calibrating a timing of a currently utilized boundary.

Abstract: An apparatus and an associated method for automatic gain control (AGC) are provided to improve the ability to lock effective signal power when interference exists, thereby upgrading the receiver performance of a communication system. The apparatus includes a variable-gain circuit for adjusting the power level of an input signal. The apparatus also includes a gain adjustment circuit and a target value adjustment circuit. The gain adjustment circuit is for adjusting the gain of the variable-gain circuit according to the adjusted input signal and a target value, while the target value adjustment is for dynamically adjusting the target value according to the strength of the adjusted input signal.