摘要:
A method for controlling the loudness of auditory events in an audio signal. In an embodiment, the method includes weighting the auditory events (an auditory event having a spectrum and a loudness), using skewness in the spectra and controlling loudness of the auditory events, using the weights. Various embodiments of the invention are as follows: The weighting being proportionate to the measure of skewness in the spectra; the measure of skewness is a measure of smoothed skewness; the weighting is insensitive to amplitude of the audio signal; the weighting is insensitive to power; the weighting is insensitive to loudness; and any relationship between signal measure and absolute reproduction level is not known at the time of weighting; the weighting includes weighting auditory-event-boundary importance, using skewness in the spectra.
摘要:
A single integrated circuit chip is provided with transistors, diodes, resistor and capacitors thereon for forming a variable gainamplifier (40) and gain control circuitry which provides a level dependent frequency response characteristic, operative at low signal levels to enhance gain at higher frequencies relative to that at lower frequencies. The gain control circuitry includes logarithmic rectifier means (48) operative to develop an AC output signal having a peak value varying as a logarithmic function of a signal level which may be that at the output of the variable gain amplifier (40). The AC output signal so developed is applied to a peak detector circuit in a compression ratio control circuit (46) to develop a DC signal which is amplified by a DC amplifier and applied to a control input of the variable gain amplifier (40).
摘要:
The equalizing arrangement in accordance with the invention comprises an equalizing unit (4) for correcting the frequency characteristic of an electric signal applied to its first input (7) under the influence of a control signal (10) applied to its second input (8) and for supplying a corrected electric signal to its output (9), and a frequency analyzing unit (16) having a first input (15) coupled to a point in the signal path between the input terminal (1) and the first input (7) of the equalizing unit (4), a second input (17) coupled to the pick-up means (14) and an output (19) for supplying the control signal (10). The analyzing unit (16) is constructed to apply a Fourier transform to the previously digitized input signals x(t) and y(t) applied to its first and its second input, to compute Fourier-transformed signals F x (f) and Fy(f) of these two signals and to compute a transfer function between these two signals. Preferably the frequency analyzing unit is further constructed to compute a coherence function γ 2 zy (f) between the two signals and, in determining the control signal, to ignore the values of the transfer function for those frequencies f for which y 2 xy is smaller than a specific value, for example 0.8. By means of the arrangement in accordance with the invention a better equalization can be achieved and the distortion of the output signal of the arrangement is low.
摘要:
When, in conventional sound systems, signals of sounds collected by a microphone are amplified and the amplified signals are applied to an ear by an earphone and a headphone, too loud sounds and environmental noises are unpleasant, and the intelligibility of words are poor. Hence, such problems are to be addressed. In addition, downsizing and performance improvement for sound apparatuses are to be accomplished. A signal having undergone an amplitude limitation with reference to an output potential of a high cut filter 17 which is an output by a low cut filter 12 in a high frequency band and inverted by an inverter 14 is added with, by an adder 15, an output signal from the high cut filter 17, and an addition signal is output.
摘要:
A digital compressor for compressing an input audio signal is presented. The digital compressor comprises a compression gain control for providing a compression gain parameter, and a compression parameter determiner for determining a compression ratio from the compression gain parameter. The compression parameter determiner may be configured to weight the compression gain parameter by a predetermined weight factor to obtain the compression ratio. The digital compressor further comprises an auxiliary signal generator for manipulating the input audio signal in dependence of the compression ratio to obtain a first auxiliary signal, and a combiner unit for combining the first auxiliary signal with the compression gain parameter to obtain a second auxiliary signal, and for combining the input audio signal with the second auxiliary signal to obtain the compressed audio signal.
摘要:
In some embodiments, a method and system for controlling distortion of the output of a miniature speaker by attenuating critical frequency band of the input signal to be reproduced, using tuning parameters that have been predetermined where the critical frequency band is a frequency range of the speaker's frequency response in which Total Harmonic Distortion (THD) peaks. The distortion control is performed in a manner which allows an increase in the average loudness of the speaker's output without significantly increasing distortion. The tuning parameters include a center frequency and a bandwidth of the critical frequency band, and a power threshold value. In some embodiments, the system is a loudness maximizer configured to limit distortion of a speaker's output by limiting distortion in a critical frequency band using predetermined control parameters, and limit the dynamic range of the output signal and increase its perceived overall average loudness level.