摘要:
In an adaptive estimation of an acoustic transfer function of an unknown system, a forward linear prediction coefficient vector a(k) of an input signal x(k), the sum of forward a posteriori prediction-error squares F(k), a backward linear prediction coefficient vector b(k) of the input signal x(k) and the sum of backward a posteriori prediction-error squares B(k) are computed. Letting a step size and a pre-filter deriving coefficient vector be represented by .mu. and f(k), respectively, a pre-filter coefficient vector g(k) is calculated by a recursion formula for the pre-filter coefficient vector g(h), which is composed of the following first and second equations: ##EQU1##
摘要:
A received signal is output to an echo path and, at the same time, it is divided into a plurality of subbands to generate subband received signals, which are applied to estimated echo paths in the respective subbands to produce echo replicas. The echo having propagated over the echo path is divided into a plurality of subbands to generate subband echoes, from which the corresponding echo replicas are subtracted to produce misalignment signals. Based on the subband received signal in each subband and the misalignment signal corresponding thereto, a coefficient to be provided to each estimated echo path is adjusted by a projection or ES projection algorithm.
摘要:
In a subband acoustic echo canceller, FG/BG filters are provided in M ones of N subbands into which the received signal is divided, and adaptive filters are provided in the other remaining subbands. In the respective FG/BG filters, during the detection of a non-double-talk state their transfer logic parts output state signals GD-j, GD-k, . . . and their adaptive operation control parts each apply an adaptation condition signal ADP to the adaptive filter in each of the above-mentioned other remaining subbands when a predetermined number or more of the FG/BG filters output the state signals GD-j, GD-k, . . . The adaptive filter updates the subband estimated echo path coefficient only when it is supplied with the signal ADP.
摘要:
In a subband echo cancellation for a multichannel teleconference, received signals x1(k), x2(k), . . . , xI(k) of each channel are divided into N subband signals, an echo y(k) picked up by a microphone 16j after propagation over an echo path is divided into N subband signals y0(k), . . . ,yN−1(k), and vectors each composed of a time sequence of subband received signals x1(k), . . . , xI(k) are combined for each corresponding subband. The combined vector and an echo cancellation error signal in the corresponding subband are input into an estimation part 19n, wherein a cross-correlation variation component is extracted. The extracted component is used as an adjustment vector to iteratively adjust the impulse response of an estimated echo path. The combined vector is applied to an estimated echo path 18n formed by the adjusted value to obtain an echo replica. An echo cancellation error signal en(k) is calculated from the echo replica and a subband echo yn(k).
摘要:
In a subband acoustic echo canceller which generates an echo replica from a subband received signal x.sub.k (m) by an estimated echo path in each subband, subtracts the echo replica from a subband echo signal y.sub.k (m) by a subtractor to generate a subband error signal e.sub.k (m) and uses an adaptive algorithm in an echo path estimation part to estimate the transfer function of the estimated echo path from the subband error signal e.sub.k (m) and the subband received signal x.sub.k (m) so that the subband error signal e.sub.k (m) approaches zero, the stop-band attenuation of each band-pass filter of a received signal subband analysis part for generating the subband received signal x.sub.k (m) is set to be smaller than the stop-band attenuation of each band-pass filter of an echo subband analysis part for generating the subband echo signal Y.sub.k (m) to thereby flatten the frequency characteristics of the subband received signals relative to the subband echo signals.
摘要:
In a multi-channel acoustic echo cancellation, received signals in a plurality of channels are radiated as acoustic signals by a plurality of loudspeakers, received signal vectors in these channels are combined into a combined vector and a rearranged received signal vector in the case of at least two channels being exchanged is generated. By inputting the combined received signal vector into an echo replica generating part which simulates echo paths from the loudspeakers to at least one microphone, an echo replica is generated. The echo replica is subtracted from an echo output from the microphone to obtain a residual echo. Based on the relationship between the received signal vector and the corresponding residual echo and between the rearranged received signal vector and the corresponding approximated residual echo, an adjustment vector is obtained which is used to adjust the estimated echo path vector representing an impulse response of the echo replica generating part.
摘要:
A variation in the cross-correlation between current received signals of different channels is extracted which corresponds to the cross-correlation between previous received signals, and the extracted variation is used as an adjustment vector to iteratively adjust the estimation of the impulse response of each echo path. Furthermore, by additionally providing a function of actively varying the cross-correlation between the received signals to such an extent as not to produce a jarring noise, it is possible to reconstruct acoustic signals by individual loudspeakers and utilize received signal added with the cross-correlation variation to obtain the adjustment vector for an estimated echo path vector.
摘要:
A measuring method of determining component concentration in a solution by calculating component concentrations in the solution at various temperatures in a small number of steps. The component concentration is measured at an arbitrary temperature T by using a solution absorbance spectrum and solvent absorbance spectrum at a plurality of wavelength(s)r, and preliminarily determining a calibration coefficient Mij (TO). Concentration of Ci of component i in solution at reference temperature TO, is obtained at differential spectrum of solution spectrum S (λj, T) at temperature T in j-th wavelength λj and solvent spectrum B (λj, T) at temperature T in j-th wavelength λj, calculating calibration coefficient Mij (TO) the specific component concentrations.
摘要:
The present invention aims to provide a PTC thermister which uses a conductive polymer having a positive temperature coefficient and has a high withstand voltage and high reliability and in which no failure in electrical connection occurs in side electrode even when a mechanical stress occurs due to the thermal shock by repeated thermal expansion of the conductive polymer sheet. It also aims to provide a method to manufacture the above PTC thermister. To achieve the above purpose, the PTC thermister of the present invention comprises (1)a laminated body made by alternately laminating conductive polymer sheets and inner electrodes, (2) outer electrodes disposed on tops and bottoms of said laminated body and (3) multi-layered side electrodes disposed at the center of both sides of said laminated body and is electrically coupled with said inner electrodes and said outer electrodes. And, a side of laminated body having an area on which a side electrode layer is formed and areas on which side electrode is not formed. A method for manufacturing a PTC thermistor comprises the steps of (1) forming a laminated body by sandwiching a conductive polymer sheet with metal foils, and then integrating them by heat pressing, (2) sandwiching the laminated body and conductive polymer sheets from the top and bottom by metal foils, and integrating them by heat pressing. A multi-layered PTC thermistor is obtained by repeating above processes.
摘要:
To provide a pulmonary disease therapeutic drug exhibiting high efficacy and reduced side effects.The pulmonary disease therapeutic drug of the invention for intratracheal administration contains biocompatible polymer nanoparticles including an HMG-CoA reductase inhibitor.