339results about "Volume compression/expansion in untuned/low-frequency amplifiers" patented technology

Output control system and method includes calculating gain for an input signal, detecting a predetermined condition, and modifying the gain calculation in accordance with one or more kneepoints to provide a varying output signal. A companding ratio is then established in accordance with the kneepoints. System gain is then adjusted, and the companding ratio may be further adjusted by adjusting one of the kneepoints relative to another.

A wearable medical device and method of detecting clipping of ECG signals is disclosed. In one embodiment, the wearable medical device comprises a plurality of ECG sensing electrodes configured to sense an ECG of a patient and an ECG acquisition circuit electrically coupled to a pair of the plurality of ECG sensing electrodes and configured to provide an amplified and conditioned analog ECG signal, a programmable attenuation / gain stage electrically coupled between a first gain stage and a second gain stage, an ADC electrically coupled to the ECG acquisition circuit to receive and digitize the amplified and conditioned analog ECG signal and provide a digitized ECG signal, and a signal conditioning and control unit electrically coupled to the ECG acquisition circuit and the ADC to receive and monitor the digitized ECG signal and to detect clipping of the amplified and conditioned analog ECG signal based upon the digitized ECG signal.

Embodiments disclosed herein enable detection and improvement of the quality of the audio signal using a mobile device by determining the loss in the audio signal and enhancing audio by streaming the remainder portion of audio. Embodiments disclosed herein enable an improvement in the sound quality rendered by rendering devices by emitting an test audio signal from the source device, measuring the test audio signal using microphones, detecting variation in the frequency response, loudness and timing characteristics using impulse responses and correcting for them. Embodiments disclosed herein also compensate for the noise in the acoustic space by determining the reverberation and ambient noise levels and their frequency characteristics and changing the digital filters and volumes of the source signal to compensate for the varying noise levels.

A method of amplification includes amplifying an input signal with a predetermined or user adjustable maximum gain to produce a second signal and compressing the dynamic range of the second signal with an automatic gain control to produce an output signal. The compression ratio of the automatic gain control is greater than one for output signals below a predetermined threshold output signal level and is essentially one for output signals above the predetermined threshold output signal level. The compression ratio may be predetermined or the method may include determining the compression ratio of the automatic gain control. The compression ratio may be determined according to the amplitude of the output signal or according to an input-output curve. The input-output curve my be predetermined and may be selected according to the auditory needs of a listener. Preferably the input-output curve is determined according to the predetermined or user adjustable maximum gain.

In accordance with an embodiment, a method includes determining an amplitude of an input signal provided by a capacitive signal source, compressing the input signal in an analog domain to form a compressed analog signal based on the determined amplitude, converting the compressed analog signal to a compressed digital signal, and decompressing the digital signal in a digital domain to form a decompressed digital signal. In an embodiment, compressing the analog signal includes adjusting a first gain of an amplifier coupled to the capacitive signal source, and decompressing the digital signal comprises adjusting a second gain of a digital processing block.

A method for processing audio signals optimizes the listening experience for hearing impaired individuals to feel stigmatized by requiring them to employ special hearing-impaired equipment. A user actuated controller controls a mixture of a preferred audio signal and a remaining audio signal across a range sufficiently wide enough to encompass all individuals. The preferred audio is recorded and maintained separate from all remaining audio and delivered to the listener in a manner that maintains the separateness of the preferred audio and the remaining audio. The user actuated controller includes the capability of automatically maintaining the listener established ratio in the face of changes in the audio signal. The user actuated controller enables the user to specify a range about the ratio in which the audio may vary, which permits the listener to expand the audio across a continuous range to whatever dynamic range his hearing can accommodate. The controller automatically adjusts to changes in incoming audio. The controller can react to relatively slowly moving changes or prevent short bursts of sound in the remaining audio from modifying the signal levels. The combination of the above aspects provides a heretofore not possible listening experience that can accommodate the listening desires of all listeners. The combination of the ability to control the ratio of preferred audio to remaining audio and to specify the dynamic range about the ratio in which the audio may vary, coupled with the ability of the controller to automatically adjust the signal levels in response to sudden changes in incoming audio, provides a powerful user capability that truly optimizes the listening experience for any listener.

An audio processor device and method is disclosed which measures and provides information relating to the audio level being applied to the ear of a user. The processor device uses a preset or calibrated sensitivity of the applied earphones in combination with an analysis of the audio stream to provide sound-pressure-level or time-weighted exposure information to the user or limit the output when preset levels have been achieved. Also disclosed is the use of microphones, internal or external, to combine an additional audio stream, typically the ambient environment, into the main audio channel.

The overall loudness of an audio track is calculated by combining a number of weighted loudness measures for segments of the audio track, where the weight applied to each individual loudness measure is a function of the loudness measure. By comparing the original overall loudness measure to a desired overall loudness measure, a gain can be determined that will adjust the loudness level to the desired value. Also disclosed is a dynamic compression method that analyzes the dynamic characteristics of an audio track and determines appropriate compressor parameters. Additionally, the loudness of a post-compressor audio track can be estimated for any given compressor parameters, thus permitting post-compression loudness matching to be done even if the compression is performed in real-time.

A single control determines both volume and the degree of compression in the reproduction of motion picture soundtracks. For some settings of the control, compression or limiting reduces the highest levels on a movie soundtrack, leaving the dialogue level substantially unchanged, thus removing the reason for complaints from the audience without the danger of making the dialogue too quiet for intelligibility.

A wearable medical device and method of detecting clipping of ECG signals is disclosed. In one embodiment, the wearable medical device comprises a plurality of ECG sensing electrodes configured to sense an ECG of a patient and an ECG acquisition circuit electrically coupled to a pair of the plurality of ECG sensing electrodes and configured to provide an amplified and conditioned analog ECG signal, a programmable attenuation / gain stage electrically coupled between a first gain stage and a second gain stage, an ADC electrically coupled to the ECG acquisition circuit to receive and digitize the amplified and conditioned analog ECG signal and provide a digitized ECG signal, and a signal conditioning and control unit electrically coupled to the ECG acquisition circuit and the ADC to receive and monitor the digitized ECG signal and to detect clipping of the amplified and conditioned analog ECG signal based upon the digitized ECG signal.

A method of matching input amplitudes in a system wherein one or more of a plurality of inputs may be selected, with each input capable of having different characteristics, involving selecting an input signal and mapping the input signal to a predetermined signal amplitude through the use of level matching logic. The level matching logic may include a gain cell for increasing or decreasing the amplitude of the input signal.

The invention provides one sound producing system including a speaker, a driving circuit and an audio controller. The speaker is used for producing an audible sound. The driving circuit is connected to the speaker. The audio controller is configured to receive an input audio signal and pre-amplify the input audio signal with an amplify gain to obtain a pre-amplified audio signal; operate a multiband dynamic range control on the pre-amplified audio signal to obtain an output audio signal; convert the output audio signal to a driving voltage; provide the driving voltage to the speaker through the driving circuit; detect over the driving circuit to obtain at least one excursion parameter to determine an estimated excursion of the speaker in response to the driving voltage; and adjust the amplify gain according to the estimated excursion.

An audio amplifier is provided having a compressor with an automatically-adjustable compressor. Compression is linked to the volume control in an inverse relationship whereby, when the volume is reduced, the compression ratio is increased to boost the listening level of quieter passages in the source material. Conversely, when the volume is increased, the compression ratio is decreased. The compression control may be physically connected to the volume control, such as in a dual-potentiometer, or may be coupled electronically, such as with a digital signal processor. An effects level control may be included to allow a listener to increase or decrease the effect of the compression by applying a multiplier to the compression ratio. An ambient noise detector may also be included such that compression is increased as ambient noise increases or exceeds a predetermined level.

Large signal peaks (for example, peaks 105 and 110) can dramatically increase the cost of a communications device by requiring high grade power amplifiers. Peak reduction can reduce the large peaks at a cost of increasing spurious emissions. A circuit (for example, circuit 500) combining a scaling window peak reducing unit (for example, unit 507) and a filter (for example, filter 509) can effectively reduce the signal peaks without significantly increasing spurious emissions.

A method for processing audio signals optimizes the listening experience for hearing impaired listeners, as well as non-hearing impaired listeners, without forcing hearing impaired individuals to feel stigmatized by requiring them to employ special hearing-impaired equipment. A user actuated controller controls a mixture of a preferred audio signal and a remaining audio signal across a range sufficiently wide enough to encompass all individuals. The preferred audio is recorded and maintained separate from all remaining audio and delivered to the listener in a manner that maintains the separateness of the preferred audio and the remaining audio. The user actuated controller includes the capability of automatically maintaining the listener established ratio in the face of changes in the audio signal. The user actuated controller enables the user to specify a range about the ratio in which the audio may vary, which permits the listener to expand the audio across a continuous range to whatever dynamic range his hearing can accommodate. The controller automatically adjusts to changes in incoming audio. The controller can react to relatively slowly moving changes or prevent short bursts of sound in the remaining audio from modifying the signal levels. The combination of the above aspects provides a heretofore not possible listening experience that can accommodate the listening desires of all listeners. The combination of the ability to control the ratio of preferred audio to remaining audio and to specify the dynamic range about the ratio in which the audio may vary, coupled with the ability of the controller to automatically adjust the signal levels in response to sudden changes in incoming audio, provides a powerful user capability that truly optimizes the listening experience for any listener.

An apparatus and method for deciding an adaptive noise level for bandwidth extension are provided. The apparatus includes a noise level decider for deciding a high-band noise level for bandwidth extension according to tonality of an input signal, a pitch frequency analyzer for detecting a pitch frequency of the input signal and analyzing correlation between the detected pitch frequency and a frequency channel, and a noise level controller for adaptively controlling the decided high-band noise level based on the analyzed correlation of the pitch frequency and the frequency channel.

The present invention relates to a signal processing apparatus and method, a program, and a data recording medium configured such that the playback level of an audio signal can be easily and effectively enhanced without requiring prior analysis.An analyzer 21 generates mapping control information in the form of the root mean square of samples in a given segment of a supplied audio signal. A mapping processor 22 takes a nonlinear function determined by the mapping control information taken as a mapping function, and conducts amplitude conversion on a supplied audio signal using the mapping function. In this way, by conducting amplitude conversion of an audio signal using a nonlinear function that changes according to the characteristics in respective segments of an audio signal, the playback level of an audio signal can be easily and effectively enhanced without requiring prior analysis. The present invention may be applied to portable playback apparatus.

Control method and apparatus for a speaker system and a mobile apparatus are provided. In an embodiment, the control apparatus includes a feedback unit, a compensation unit, and a gain unit. The feedback unit, in response to at least one feedback signal from a speaker, is for generating at least one detected parameter. The compensation unit, in response to a first audio signal, is for generating a second audio signal, wherein the second audio signal is generated selectively by compensation according to a first model for the speaker, a first detected parameter of the at least one detected parameter, the first audio signal, and a gain value. The gain unit, coupled to receive the second audio signal and coupled to receive one or more of the at least one detected parameter, is for outputting the gain value and generating a third audio signal according to the gain value.

In one embodiment, a method for speaker operation comprises sensing an input common mode signal of a driver, wherein the driver drives a speaker, and adjusting the input common mode signal of the driver based on a difference between the sensed input common mode signal and a reference signal. The method also comprises sensing a current of a coil of the speaker, and control an output volume of the speaker based at least in part on the sensed current.

An audio signal control method and apparatus for hearing protection are disclosed. The audio signal control method includes: producing an output level of an audio signal being input; determining whether the ratio of an output time of the audio signal within a preset time duration to a permissible time corresponding to the produced output level is greater than or equal to a limit reference value; and limiting, when the ratio of the output time to the permissible time is greater than or equal to the limit reference value, the output level of the audio signal to a preset level.

An audio dynamics processor or processing method that uses a reset mechanism or process in order to adapt quickly to content changes in the audio signal. A reset signal may be generated by analyzing the audio signal itself or the reset may be triggered from an external event such as a channel change on a television set or an input selection change on an audio / visual receiver. In the case of an external trigger, one or more indicators of the state of the dynamics processor for a current audio source may be saved and associated with that audio source before switching to a new audio source. Then, if the system switches back to the first audio source, the dynamics processor may be reset to the state previously stored or an approximation thereof.

A handheld electronic, a sound produce system and control method of sound producing thereof are provided. The sound produce system includes a speaker, a feedback unit, a gain unit and a compensation unit. The speaker generates audible sound according to an output audio signal. The feedback unit generates a first detected parameter, wherein the first detected parameter represents a detected excursion. The gain unit receives an input audio signal, and amplifies the input audio signal to generate a gained audio signal according to a gain value. The compensation unit receives the gained audio signal and the first detected parameter, and predicts an excursion of the speaker corresponding to the gained audio signal to generate a predicted excursion parameter, and compensates the gained audio signal to generate the output audio signal according to the first detected parameter and the predicted excursion parameter.

The invention concerns a method (300) and system (100) for controlling audio output. The method includes the steps of inputting (312) an audio signal and a voltage level signal, measuring (314) the audio signal and the voltage level signal, mapping (316) the audio signal against at least one table (134) of predetermined corresponding gain targets (138) and selecting (318) at least one gain target for the audio signal. The mapping step and the selecting step are based at least in part on the measurement of the voltage level signal and the measurement of the audio signal. The method also includes the step of applying (320) the gain target to the audio signal.

A loudspeaker drive circuit uses a dynamic range compressor to implement a non-linear gain function between the input signal to the dynamic range compressor and an output signal from the dynamic range compressor. The output is used to drive a loudspeaker, and the operating parameters of the dynamic range compressor are varied in dependence on a criterion, such as the estimated voice coil temperature, the power consumption or the acoustical distortion.

A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has gate voltage and substrate voltage which can be pulled down to negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage.

Embodiments of the invention disclose a sound effect processing method and a terminal device. The sound effect processing method can comprise the steps of detecting a maximum volume difference of an audio clip of a currently read audio file when the terminal device plays the audio file, wherein the maximum volume difference is a difference value between maximum volume and minimum volume of the audio clip; if the maximum volume difference is greater than a preset difference value, determining a first sub-clip with the volume greater than first preset volume in the audio clip; and reducing playing volume of the first sub-clip. With the adoption of the embodiments of the method and the terminal device, the playing volume of the audio clip with excessively high volume in the audio file can be reduced in advance, so that the hearing of users is protected and the sound effect power consumption of the terminal device is reduced.