Tone Signal Generation Research Articles

A Monolithically Integrated Laser-Photodetector Chip for On-Chip Photonic and Microwave Signal Generation

An Indium-phosphide-based monolithically integrated photonic chip comprising of an amplified feedback laser (AFL) and a photodetector was designed and fabricated for on-chip photonic and microwave generation. Various waveforms including single tone, multi-tone, and chaotic signal generation were demonstrated by simply adjusting the injection currents applied to the controlling electrodes. The evolution dynamics of the photonic chip was characterized. Photonic microwave with frequency separation tunable from 26.3 GHz to 34 GHz, chaotic signal with standard bandwidth of 12 GHz were obtained. An optoelectronic oscillator (OEO) based on the integrated photonic chip was demonstrated without using any external electrical filter and photodetector. Tunable microwave outputs ranging from 25.5 to 26.4 GHz with single sideband (SSB) phase noise less than −90 dBc/Hz at a 10-kHz offset from the carrier frequency were realized.

Research on the Key Technique of SPC Exchange Equipment Based on FPGA

In the program controlled exchange technology college course, the signal transmission and voice data exchange for the communication system were usually achieved by utilizing the program controlled telephone exchange equipment choosing MT8980 series chip as the processing core which was limited to the numbers of communication channels and inflexibility of information interchange manners. A variety of extern circuits, taking time slice generation circuit and tone signal generation circuit as examples, will even be required which directly causes the complexity of the whole structure. Considering the disadvantages referred above, a new method of SPC (Stored Program Control) exchange exploiting FPGA (Field Programmable Gate Array) is proposed in this paper. The time slice generation, signal tone generation, user calls, voice data exchange functions, as well as other secondary functions, were realized by applying the new approach which allows the further development through hardware in-system programming. The superiority of the means is furnished in the end via comparing the experimental data in detail. DOI: http://dx.doi.org/10.11591/telkomnika.v11i7.2830

HEARING AID HAVING AN AUDIO SIGNAL GENERATOR AND METHOD

The invention relates to a hearing aid having a sound receiver and a sound generator. The hearing aid also has an audio signal unit that is functionally linked to the sound generator and has a tone signal generator for generating a tone signal as a function of a trigger signal and of a generation parameter which represents a frequency that can be perceived by a human ear. The hearing aid also has a memory, connected to the tone signal generator, for storing the generation parameter. The audio signal unit changes the generation parameter stored in the memory, generates a trigger signal for each tone signal requiring to be generated, sends said trigger signal to the tone signal generator, and sends the generated tone signal to the sound generator.

Electric musical instrument

An electric musical instrument is provided, which enables rich and diverse expressions to be achieved in musical performance. A driving member drives a tone generating source. A driving member-side signal generator obtains a signal from the driving member and outputs the obtained signal. A musical tone signal generator generates a musical tone signal using the signal output by the driving member-side signal generator and outputs the generated musical tone signal. In another aspect of the invention, a tone generating source-side signal generator obtains a tone generating source-side signal from the tone generating source and outputs the obtained signal, and a driving member-side signal generator obtains a driving member-side signal from the driving member and outputs the obtained signal. A modulation device frequency-modulates one of the tone generating source-side signal and the driving member side signal with the other signal. The modulated signal is output from the modulation device as a sound.

Electronic musical instrument for modulating musical tone signal with voice

An electrical musical instrument includes a scale designator for sequentially and automatically designating a scale on the basis of prestored data of a music piece, and a musical tone signal generator for outputting a musical tone signal including a harmonic frequency on the basis of the scale designated by said scale designator or as a fundamental frequency. A voice detector detects an external voice and the detected voice is divided by a modulator into voice signals in a plurality of frequency ranges. The musical tone signal is modulated in units of corresponding frequency ranges on the basis of the voice signals divided into the plurality of frequency ranges.

Tone signal generation device having waveshape changing means

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Tone signal generation device with resonance tone effect

A circuit for adding a resonance tone to a tone signal to be generated is provided. When a damper operator is not operated, the resonance tone is not added but an ordinary tone signal is generated. When the damper operator has been operated, the resonance tone is added so that a tone signal including the resonance tone is generated. An effect of a damper operator, i.e., loud pedal, in a piano, a natural musical instrument, is thereby simulated with high fidelity. The resonance tone may be produced by passing an ordinary tone signal through a filter. Alternatively, data obtained by sampling an actually produced tone of a piano, a natural musical instrument, when a damper operator, i.e., loud pedal, is ON may be stored in a memory and a resonance tone may be generated by reading out the stored data from the memory. The signal of the generated resonance tone may be sounded by itself or after mixing with an ordinary tone signal at a suitable mixing ratio. In addition to the imparting of the resonance tone, a known control for switching of a decay rate of a tone volume envelope may be performed.

Tone signal generation device

A note clock generation circuit (15) generates note clock pulses in correspondence to a note name of tone to be generated. An octave rate data generation circuit (14) generates rate data in correspondence to the octave range to which the tone to be generated belongs. By performing addition or subtraction of the rate data at the timing of generation of the note clock pulses, an address signal is generated. A tone generator (17) generates a tone : waveshape in the form of amplitude sampled values in response to an integer section of this address signal. An interpolation circuit (18) performs interpolation between adjacent amplitude sampled values thus generated in response to a decimal section of the address signal. The rate of change of the decimal section of the address signal is changed in accordance with the tone range so that a finer interpolation is made as the tone range becomes lower. By this arrangement, decrease in an effective sampling fequency in the lower tone range can be prevented. The interpolation circuit (18) receives the amplitude sampled values and the interpolation parameter (i.e., the decimal section of the address signal) respectively in a pitch synchronized state and performs the interpolation operation in the pitch synchronized state. The timing of the interpolation operation thereby is synchronized with the pitch of the generated tone so that inharmonic noise components are substantially removed.

Tone signal generation device of sampling type

In a tone signal generation device, original waveshape amplitude data corresponding to a waveshape signal from an external source is stored in a first memory. Waveshape data is read out from this first memory and is properly modified by a tone processing circuit such as a filter or a modulation effect circuit. The modified waveshape data is reserved in a second memory. The waveshape data stored in the second memory is selectively transferred to the first memory. In this manner, the original waveshape data initially stored in the first memory can be freely modified and a tone can be produced with a high degree of freedom as in a music synthesizer.

Tone signal generation device for an electronic musical instrument

A basic tone signal generator and a difference signal generator are provided. A desired tone signal is obtained by synthesizing a basic tone signal and a difference signal generated from these generators respectively. The basic tone signal has principal characteristics of a desired tone signal whose tone color (waveshape) changes subtly with time as in a tone of an acoustic musical instrument, but it is not the desired tone signal itself, including some errors, i.e., difference from the desired tone signal. The difference signal represents the difference between the desired tone signal and the basic tone signal. Since the basic tone signal is constituted by basic tone data whose data amount can be substantially reduced as compared to an amount of data required for reproducing the desired tone signal itself with a high resolution and the difference signal is constituted by difference data whose data amount can be very small. Therefore, a tone synthesization by combining the basic tone signal and the difference signal contributes greatly to the simplification of the circuit construction of an electronic musical instrument.

Tone signal generation device

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Keyboard musical instruments with transpositional function

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Tone signal processing device

A digital filter is provided between a tone signal generation circuit which supplies a digital tone signal in accordance with a first sampling frequency and a sampling circuit which resamples this digital tone signal in accordance with a second sampling frequency which is lower than the first sampling frequency. This digital filter filters the input digital tone signal with such amplitude-frequency characteristics as to be able to substantially remove an aliasing noise produced due to the second sampling frequency (e.g., with low-pass filter characteristics having a cut-off frequency which is 1/2 the second sampling frequency). This removes high frequency components producing an aliasing noise from the digital tone signal before it is applied to the resampling circuit whereby generation of the aliasing noise in resampling is prevented. The resampling is performed for adapting the digital tone signal to an operation clock frequency of an effect imparting circuit provided in a posterior stage for imparting, in digital, a tone effect such as a modulation effect to the digital tone signal.

Tone signal generation device for changing the tone color of a stored tone waveshape in an electronic musical instrument

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Tone signal generation device for an electronic musical instrument

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System for expanding the dynamic volume range of electronic musical instruments

An electronic musical instrument wherein depression of a key entails the discharge of a primary capacitor which is connected to the inverting input of an operational amplifier whose output is connected with a second capacitor serving to supply envelope control voltage signals to an analog switch which connects a tone signal generator with a tone processing unit. The extent to which the primary capacitor discharges depends on the speed of movement of the key from non-depressed to depressed position, and the intensity of residual voltage of the partially discharged primary capacitor determines the intensity of the envelope control voltage signal. The speed at which the second capacitor discharges can be regulated to produce sustain or banjo effects. The second capacitor is in series with a resistor in a feedback conduit connecting the output and the input of the operational amplifier. A second feedback connection contains a diode which ensures that a reference potential is applied to the input of the operational amplifier while the primary capacitor is charged in non-depressed position of the key.

Apparatus and method for generating chorus and celeste tones

The operation of the chorus generator of FIG. 3 may be summarized as follows. The generation of a realistic chorus tone depends upon the simultaneous amplitude and phase modulation of a tone signal which initially has little or no choral characteristics. When a tone signal generator is so modulated, the derived audio tone from a loudspeaker will exhibit choral characteristics. A random low frequency signal generator serves as an input to both the amplitude and phase modulation channels. The amplitude modulation signal is merely a suitably delayed replica of the low frequency signal. The phase modulation signal is derived from the low frequency signal by first modifying its amplitude excursions by means of a function generator and then filtering the derived signal by means of a suitable non-minimum phase shift filter.

Percussion simulating techniques

The disclosure describes an improved electronic musical instrument capable of simulating a sound resulting from the striking of a natural percussion instrument. The electronic instrument includes playable keys, a tone signal generator for generating tone signals and an output circuit for converting the tone signals to audible tones. A control circuit responsive to the depression of any one of the keys enables one or more of the tone signals representing one or more fundamental pitches to be transmitted to the output circuit for a first time period and enables another tone signal representing a pitch nonharmonically related to the fundamental pitches to be transmitted to the output circuit for a second time period less than the first time period. By combining the tone signals corresponding to the fundamental and nonharmonic pitches, the sound of a percussion instrument is simulated.