Abstract: A method and device for detecting a force factor of a loudspeaker is provided. The method includes the steps of: providing the loudspeaker with a dynamic driving voltage signal; continuously measuring a current signal flowing through the loudspeaker; observing the current signal and if the current signal shows that the diaphragm excursion of the loudspeaker is greater than an displacement limit, decreasing the driving voltage signal until the current signal shows that the diaphragm excursion of the loudspeaker is less than or equal to the displacement limit; and substituting the current driving voltage signal, the current signal, the displacement limit, and an electrical impedance of the loudspeaker into a function so as to compute the force factor of the loudspeaker.

Abstract: A method and device for detecting a force factor of a loudspeaker is provided. The method includes the steps of: providing the loudspeaker with a dynamic driving voltage signal; continuously measuring a current signal flowing through the loudspeaker; observing the current signal and if the current signal shows that the diaphragm excursion of the loudspeaker is greater than an displacement limit, decreasing the driving voltage signal until the current signal shows that the diaphragm excursion of the loudspeaker is less than or equal to the displacement limit; and substituting the current driving voltage signal, the current signal, the displacement limit, and an electrical impedance of the loudspeaker into a function so as to compute the force factor of the loudspeaker.

Abstract: A method and device for generating a driving signal of a loudspeaker is provided. The method includes the steps of: outputting a driving voltage to a loudspeaker; measuring a current flowing through the loudspeaker; calculating to derive a voltage value corresponding to the current flowing through an electrical impedance of the loudspeaker, and calculating to derive a back-emf value by performing subtraction according to the driving voltage or a corresponding value thereof and the voltage value; integrating the back-emf value to derive an integrating value positive-correlating to a displacement of the diaphragm of the loudspeaker; and manipulating the driving voltage according to the integrating value to perform protection on the loudspeaker.

Abstract: A sample rate converter receives an input signal with an input sample rate, and generates an output signal with an output sample rate. The sample rate converter includes: a rate estimator, a polynomial interpolation calculation circuit, an up sampling filter, and a down sampling filter. The rate estimator includes: a subtractor, which generates an error signal according to an input clock signal and a second order rate signal; a first order integrator, which generates a first order rate signal according to the error signal; and a second order integrator, which generates the second order rate signal according to the first order rate signal.

Abstract: A phase/frequency detector module, applicable to a digital phase-locked loop, includes: an edge detector for receiving a reference clock signal and a counting clock signal, where when a positive edge of the counting clock signal occurs, if a positive edge of the reference clock signal has occurred, the edge detector outputs an edge-detected signal, else the edge detector outputs an edge-not-detected signal; a counter coupled to the edge detector, where if receiving the edge-detected signal, the counter outputs a counting result forming a frequency error signal, resets, and loads a count value, and if receiving the edge-not-detected signal, the counter continues to count on the positive edge of the counting clock signal; and a frequency phase converter for performing integration over the counting result, where the integral forms a phase error signal.

Abstract: A method for approximating an upper bound limit for the absolute value of a complex number or the norm of a two-element vector is disclosed. An upper bound approximation algorithm is used to minimize software implementation efforts and make the hardware implementation less expensive. The hardware implementation of the upper bound approximation algorithm only requires a multiplier element and an adder element. Therefore, this algorithm can be implemented anywhere in a digital signal processing apparatus without increasing cost significantly. Moreover, the hardware employing the present invention can be implemented in a pipeline architecture configuration to achieve a real time function in digital audio or digital video applications.

Abstract: An impulsive noise suppresser and method thereof is provided. The impulsive noise suppresser includes an automatic gain control unit, variable gain amplification unit, impulsive detection unit and impulsive suppression unit. The automatic gain control unit determines a gain value according to a PAPR. The variable gain amplification unit amplifies a reception signal by the gain value. The gain value is determined such that the amplified reception signal as unaffected by the impulsive noise can have an amplitude range smaller than a predetermined range. The impulsive detection unit is coupled to the variable gain amplification unit for determining whether the amplified reception signal is larger than a maximum value of the predetermined range and outputting an impulsive alarm signal if the reception signal is larger than the maximum value. The impulsive suppression unit suppresses the impulsive noise as receiving the impulsive alarm signal, and then outputs an output signal.

Abstract: A method for approximating an upper bound limit for the absolute value of a complex number or the norm of a two-element vector is disclosed. An upper bound approximation algorithm is used to minimize software implementation efforts and make the hardware implementation less expensive. The hardware implementation of the upper bound approximation algorithm only requires a multiplier element and an adder element. Therefore, this algorithm can be implemented anywhere in a digital signal processing apparatus without increasing cost significantly. Moreover, the hardware employing the present invention can be implemented in a pipeline architecture configuration to achieve a real time function in digital audio or digital video applications.

Abstract: An impulsive noise suppresser and method thereof is provided. The impulsive noise suppresser includes an automatic gain control unit, variable gain amplification unit, impulsive detection unit and impulsive suppression unit. The automatic gain control unit determines a gain value according to a PAPR. The variable gain amplification unit amplifies a reception signal by the gain value. The gain value is determined such that the amplified reception signal as unaffected by the impulsive noise can have an amplitude range smaller than a predetermined range. The impulsive detection unit is coupled to the variable gain amplification unit for determining whether the amplified reception signal is larger than a maximum value of the predetermined range and outputting an impulsive alarm signal if the reception signal is larger than the maximum value. The impulsive suppression unit suppresses the impulsive noise as receiving the impulsive alarm signal, and then outputs an output signal.