DIGITAL TONE CONTROL MENGGUNAKAN MIKROKONTROLLER 8-BIT

The quality of the audio sound system that is generated depends on the tone control. Good audio tone control signal output produces an audio signal that approaches the input audio signal. Tone controls are generally used on audio sound system devices using potentiometers as regulating devices. Potentiometers are done in charcoal powder which has varying and linear barriers. Problems that often arise in potentiometers in the form of quick wear due to frequent friction, the output of the tone control will produce a noise when the relationship between the powder charcoal and the sweeping lever is not well connected, and linearity will change if the potentiometer is dirty due to dust. Microcontroller is electronic equipment that can be programmed according to user need. With a collaboration push button, Multiplexer and Analog to digital converter (ADC), can be utilized instead of a potentiometer. Setting the potentiometer is done by pressing the digital control tune up / down button. Based on the testing of the tone control on the volume setting, the input signal has strengthened 6.02 dB. In the bass setting, a signal with a frequency of 100-1 khz is passed, while the frequency of 2.5 khz is muted. In the treble setting, the frequency passed is 2.5 khz to 16 khz.

RELIABLE DETECTION OF SIGNAL TONES IN PRESENCE OF COLLISIONS

A reliable and energy-efficient contention resolution mechanism (CRM) is a crucial component of MAC protocols for wireless sensor networks (WSNs). Among a number of CRM proposals, CRMs based on exchanging short signal tones between competing nodes have recently drawn attention due to their promise of collision-freedom and energy-efficiency. However, the basic assumption of these protocols, i.e. the possibility to reliably detect the presence/absence of signal tone in case of simultaneous transmissions from multiple nodes, has not yet been confirmed. In this paper we present a technique for signal tone generation/detection, which uses only standard features of off-the-shelf RF transmitters. Furthermore, we present results of an experimental validation carried out in a real testbed which demonstrate a high accuracy of signal tone detection in presence of multiple simultaneous transmissions.

Realization of Signal Tone Detection in Power Line Carrier Terminal

—when the noise cancellation system ( NC ) is used in the down link of the power line carrier terminal, it can cancel the background noise and narrowband interference, but the downlink signal tone distorts at the same time. This is because the VAD algorithm of the NC system is sensitive to dramatic changes in the power of signal tone. Through detailed researches on time frequency characteristics of signal tone and error factors of network transmission, a new signal tone detection algorithm that applicable to downlink NC system was put forward, The algorithm detects signal tones through changes of frequency-domain power and time-domain signal period of every frame. After theoretical evaluation and practice tests, it is observed that the above-mentioned algorithm can correctly detect signal tones without influence on functions of the NC system, so as to avoid the occurrence of distortion.

SPC Exchange Experiment System Based on FPGA

In this paper, we propose a new type of SPC (Stored Program Control) exchange experiment system, which adapt to the reform of the program-controlled exchange technology experiment teaching. The system uses FPGA chip to complete the core of telephone exchange such as timeslot generation, signal tone generation, user calls, voice data exchange functions, it can also achieve secondary development and teaching function expansion through the online programming downloads. The PC software in the system completes the user calls data statistics and analysis function. The experiment system in use reflects its development and convenient, the function is perfect characteristics, and has good application prospect.

A Psychophysiological Study of Auditory Illusions of Approach and Withdrawal in the Context of the Perceptual Environment

Auditory perception of the depth of space is based mainly on spectral and amplitude changes of sound waves originating from the sound source and reaching the listener. The perceptive illusion of movement of an auditory image caused by changes in amplitude and/or frequency of the signal tone emanating from an immobile loudspeaker was studied. Analysis of data obtained from the participants revealed the diapason of combinations of amplitude and frequency changes for which the movement direction was perceived similarly by all participants, despite significantly different movement assessment criteria. Additional auditory and visual information of the conditions of radial movement (near or far fields) determined listeners' interpretation of changes in the signal parameters. The data obtained about the perception of approach and withdrawal models are evidence of the fact that the principal cues of the perception of the distance of immobile sound sources manifests similarly to that of an auditory image moving along a radial axis.

Effects of Auditory Imagery on the Detection of a Pure Tone in White Noise: Experimental Evidence of the Auditory Perky Effect

The purpose of this study was to examine whether the auditory image of a pure tone facilitates or interferes with the auditory perception of the pure tone. The masked threshold of a pure tone in white noise with and without the image of a pure tone was compared. It was shown that, in contrast to Farah and Smith's (1983) finding of facilitation, imagery interfered with the detection of the pure tone only when the frequency of the imagined tone and the detected tone was the same. This interference was interpreted as showing the assimilation of the signal tone into imagery, i.e., the effect described by Perky in 1910, occurred in the auditory modality. An explanation of the differences between findings of interference and facilitation is offered.

Short-Term Stability Measures for the Evaluation of Vocal Quality

The vocal quality of 64 normal subjects and 57 subjects suffering various degrees of glottal cancer was investigated using acoustic measures of six different aspects of the voice signal: tone period perturbation, amplitude perturbation, waveform perturbation, vocal noise, spectral periodicity and spectral distortion. The measures were estimated taking the glottal cycle as temporal reference unit to make the influence of the differences in tone period from one person to another as low as possible. The measures were evaluated with regard to (a) their ability to discriminate between healthy and sick subjects, and (b) their correlation with the perceptual evaluation of four trained listeners. The results suggest that signal processing techniques are unsatisfactory for clinical diagnoses but useful for monitoring voice quality.

Modification of the Autonomic Component of the Conditioned Emotional Response

A series of experiments was conducted to clarify the role of the autonomic nervous system in the acquisition and maintenance of the conditioned emotional response (CER). In Exp. 1 the reactivity of either the sympathetic or the parasympathetic system was altered by drugs during maintenance testing of the CER. 12 rats were trained to bar-press for sugar water on a VI 30-sec. schedule; 6 CER trials were administered during each 2-hr. session. The intensity of the unconditioned stimulus (electric shock) was adjusted for each S so as to suppress responding during the CER signal (tone) to approximately 50% of normal pressing rate. Neither the sympathetic agents (adrenalin, Chlorpromazine, Dibenzyline), nor the parasympathetic agents (methacholine chloride, propantheline, atropine sulfate) reliably altered bar-press rates during the CER trials. Exp. 2 demonstrated that the autonomic agents, in the dosages used, were in fact altering autonomic reactivity as indexed by heart-rate measures. In Exp. 3 acquisition of the CER by 18 rats was found not to be affected by autonomic alteration as produced by drugs.