Abstract: A noise control system for a FM stereo receiver senses the presence of noise outside of the FM stereo transmission bandwidth at an output of a FM detector and uses variations of amplitude of the sensed noise to control stereo channel separation and audio bandwidth control circuits of a stereo decoder circuit of the stereo receiver.

Abstract: The present invention relates to a correcting apparatus of sound signal distortion by way of an audio frequency pass segmentation, the apparatus comprising: frequency band segmentation means for segmenting an audio frequency band sampled by a predetermined frequency into a plurality of bands; decimation means for performing a decimation in respectively different ratios in accordance with a sound data band band-segmented by the frequency band segmentation means; distortion correcting means for performing a distortion correcting on the sound data decimated from the decimation means per band; and data output means for synchronizing the sound data distortion-corrected at the distortion correcting means so that the sound data can be in the same order as the sound data when input to the frequency band segmentation means to thereby b output in synthesis.

Abstract: A noise-canceling method for simultaneously canceling a plurality of harmonic components of the engine rotational speed contained in engine noise. Reference signals are generated in correspondence with a plurality of harmonic components, and an adaptive signal processing is executed by using each reference signal, a composite-sound signal of the engine sound and a composite noise-canceling sound at a noise-canceling point, thereby generating a noise-canceling signal. The noise-canceling signal is input to a speaker. The reference signal corresponding to a harmonic component of a low level is multiplied by a constant K before it is input to the speaker so as to approximately equalize the levels of all the harmonic components at the noise-canceling point.

Abstract: A motional feedback loudspeaker system wherein the loudspeaker distortion is reduced by a negative feedback signal derived from the back electromotive force induced by the motion of the voice-coil within the magnet field. It is essential that the feedback signal be a linear function of the loudspeaker cone motion, and this is achieved by locating the voice-coil within a uniform elongated cylindrical magnetic field of substantially constant flux density and having an axial length substantially greater than the axial length of the voice-coil. Therefore the voice-coil is underhung so as to remain immersed within the uniform field even at peak displacements of the voice-coil during maximum excursions of the speaker cone. The uniform elongated magnetic field is preferably provided by a cylindrical radially polarized magnet of neodymium.

Abstract: An intelligent speaker unit is controlled by control data transmitted with the digital audio data. The intelligent speaker has a Digital Signal Processor (DSP) for processing the audio data in accordance with the control data. The control data contains an address to select the speaker unit. The DSP for the speaker unit processes audio data digitally based on parameters in the control data. The processed digital audio data is then converted to an analog signal which is amplified and applied to the speaker. The digital audio data is time division multiplexed on a TDM bus. Each time slot on the TDM bus contains audio data for one digital audio channel. The control data is placed on the TDM bus as one channel (time slot) or is distributed as control bits through all the other channels. The control data also contains channel select data. Accordingly the DSP in a selected speaker unit may in turn select its audio data from a plurality of audio channels based on the control data the DSP receives.

Abstract: A multimedia controller apparatus provides for computer programmed volume control and summing of audio signals in an enhanced multimedia environment. The apparatus is capable of receiving and processing inputs from a CD-ROM FM synthesizer, general MIDI audio, microphone, PCM sampled sound, and telephony systems. From these inputs, it produces outputs for PCM sampled sound, telephony systems, and stereo line-out. Additionally, it provides for the integration of telephonic support functions into a multimedia system. The multimedia controller apparatus comprises a volume control portion for receiving and controlling the volume of a plurality of analog input signals. The volume controlled input signals are then combined by an aggregation portion. A telephony processing portion is also provided for processing the telephony input signals. Stereo outputs, mono outputs, digital samplable outputs, and telephony outputs can be formed from the combined analog and telephony signals by an output portion.

Abstract: An improved audio mixing system. The system is not limited to one type of microphone and does not depend on separate sensing microphones to determine the background noise level. In addition, the active signal is not amplitude modulated by extraneous noise inputted through inactive microphones. The mixing system divides the system gain between a plurality of input channels. The mixing system periodically samples the channels and determines which channel is the dominant channel. In response to this determination, the gain of the dominant channel is increased and that of the other channels decreased.

Abstract: A self-contained, hand-held device for testing an aircraft helmet communication system including a microphone and earphones in which a selection switch on the housing of the device is movable from an off position to a talk-through position at which the microphone is connected to both the earphones and a volume indicator on the housing and to a self-test position in which actuation of a pushbutton switch on the housing applies the output of an oscillator both to the volume indicator and a circuit having a voltage divider made up of a potentiometer and a fixed resistance to provide a self-test signal which energizes an illuminable element on the housing if the device is functioning properly and to an earphone impedance test position at which the output of the oscillator is applied to a circuit having a voltage divider made up of the potentiometer and the earphones to produce an earphone impedance-test signal which energizes the illuminable element if the earphone impedance is of the correct value.

Abstract: A method that can be used not only for elimination of noise, for example in automatic speech recognition, but also to improve the voice quality for people, for instance during use of the speaker function of a car phone. The noise reduction is executed with two or multiple channels in such a manner that the temporal and architectural acoustical signal properties of speech and interference are utilized step-by-step and systematically. According to the method a pivotable, acoustic directional lobe is produced for the individual voice channels by respective digital directional filters and a linear phase estimation to correct for a phase difference between the two channels. The noise in the individual voice channels is estimated during speaking pauses, and the temporally stationary noise sources are damped by means of spectral subtraction. The individual voice channels are subsequently added whereby the statistical disturbances of spectral subtraction are averaged.

Abstract: A volume/balance control apparatus includes a plurality of resistance arrays which correspond to a plurality of channels, a volume operator and a balance operator which generate volume and balance signals according to user's operation, an operation signal synthesizing means for producing synthesized control signals pertinent to each channel by synthesizing the volume signal and balance signal, and a plurality of decoders for decoding the output from the operation signal synthesizing means and applying the result to a switching element included in each resistance array. The volume/balance control apparatus has only one resistance array per channel, thereby improving noise characteristics, and permits the independent operation of volume and balance controls, thereby enhancing user convenience.

Abstract: A high quality stereophonic sound enclosure system high resolution intended for computer visual display monitors employing cathode ray tubes (CRTs) having a vertical aperture grill, and methods for construction of same. The aperture grill has a natural frequency centered within the musical scale. The stereo speaker system comprises a ported speaker enclosure within which are mounted two conventional cone speaker assemblies. A stereo audio amplifier and control unit for controlling the audio signals delivered to the speakers is mounted within the speaker enclosure. The speaker enclosure is internally mounted within the monitor with a minimum number of attachment members incorporating vibration isolation material to remove vibration components near the natural frequency of the aperture grill. The speaker enclosure is internally reinforced to reduce structural deformations which contribute to airborne transmitted vibration within the monitor housing when the speaker system is operating.

Abstract: A system for marking a singing voice and displaying a marked result for a karaoke machine. The system comprises a data storage means, a comparison and marking means, a display means, a control mean. The data storage means stores a standard singing voice data on a basis of which a singing voice of a singer inputted from a microphone is marked. The comparison and marking means compares the singing voice with the standard singing voice data and marks the singing voice. The display means displays a result of a score of the singing voice marked by the comparison and marking means, and has a course which is composed of a series of display units and a goal display. The control means controls the display means.

Abstract: A system for connecting an audio object to various multimedia objects to enable an object-oriented simulation of a multimedia presentation using a computer with a storage and a display. A plurality of multimedia objects are created on the display including at least one connection object and at least one audio object in the storage. Multimedia objects are displayed on the display, including at least one audio object. The multimedia object and the audio object are connected, and information is routed via the connection between the multimedia object and the audio object to create a multimedia presentation.

Abstract: An active acoustic attenuation system attenuates a correlated input acoustic wave and eliminates the need for an input transducer sensing such wave and also eliminates the need to sum a filtered modification of the model output correction signal with the error signal as an input to the model. The error signal is instead summed with the model input signal provided through a model copy, and the output resultant sum is supplied as the input to the model. A summer sums the error signal from the error transducer and the output of a copy of the adaptive filter model and supplies the resultant sum to the model input. Another copy of a model modeling the output transducer and the error path between the output transducer and the error transducer is connected in series between the model input and the input of the first noted model copy.

Abstract: In a noise suppressor, a noise signal detected by a first detector is inputted to an adaptive filter and a FIR filter. An output signal of the adaptive filter is reproduced by a speaker. The signal reproduced by the speaker and a noise signal from a noise source are detected by a second detector. The signal detected by the second detector is band-limited by a filter circuit and sent to a LMS computing circuit. The LMS computing circuit updates a coefficient of the adaptive filter so as to minimize an output signal of the filter circuit in response to an output signal of the FIR filter and an output signal of the filter circuit.

Abstract: An apparatus for active reduction of noises transmitted from a noise source into a space. The active noise reduction apparatus comprises residual noise sensors for detecting the residual noises in the space. A reference signal is produced based upon the noise generating condition of the noise source. The reference signal is used, along with the detected residual noises, to drive control sound sources so as to reduce the noises in the space. A filter is adjusted to correspond to acoustic transfer characteristics between the control sound sources and the residual noise sensors. An identification sound is generated to correspond to the background noise level detected in the space and to the spectral distribution of the noises transmitted into the space. The coefficients of the filter are updated according to acoustic transfer characteristics between the control sound sources and the residual noise sensors.

Abstract: An active noise controller includes a prediction filter which includes a delayer for delaying the noise or error detection signal by a predetermined period of time, a first adaptive filter for processing the output of the delayer to deliver its periodic component, and a subtractor for subtracting the output of the first adaptive filter from the noise detection signal to deliver a random component of the signal. More specifically, the prediction filter is capable of dividing the noise or error detection signal into two, periodic and random, components. In addition, two, second and third, adaptive filters are provided for processing the periodic and random components respectively. Accordingly, the second and third adaptive filters become responsive precisely to their respective periodic and random components regardless of the ratio in level between the two components, whereby any undesired noise consisting of the two discrete components will be suppressed.

Abstract: Apparatus and methods for enhancing an electronic audio signal by adding enhancing harmonics to the electronic audio signal. The present invention includes a field inducing coil through which input electronic audio signals are to be transmitted to set up an electromagnetic field. The field inducing coil is weakly coupled to an electromagnetic field receptor such that when an input electronic audio signal is transmitted through the inducing coil only a small portion of the electromagnetic field cuts or passes through the field receptor in order to produce an induced electronic audio signal having a greater harmonic content than the input electronic audio signal.

Abstract: An AM stereo receiver in which a synchronous in-phase signal is determined comprises a low pass filter circuit for determining an average DC value of the synchronous in-phase signal, a reference voltage supply for providing a reference voltage indicative of a predetermined portion of the DC value of the synchronous in-phase signal occurring during a 100% IF signal level condition, a comparison circuit for comparing the average DC value of the synchronous in-phase signal to the predetermined reference, and an output circuit outputting a signal indicative of an out-of-lock condition when the average DC value of the synchronous in-phase signal falls below the predetermined reference.

Abstract: A microphone apparatus including a vacuum-tube amplifier amplifying an electric signal converted from an acoustic signal includes a thermo-ionic cooling element having two surfaces, in which a first surface is in contact with the vacuum-tube amplifier for absorbing the heat generated from the vacuum-tube amplifier and the absorbed heat is radiated to the exterior from the second surface.