Sine wave

About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.

Continuous and discontinuous sine wave synthesis of speech signals from harmonic data of different pitch periods

Abstract: A method for decoding encoded speech signals uses sine wave synthesis based on harmonics of the original speech signal. The harmonics are obtained by transforming the original speech signal from a time domain to a frequency domain, and the harmonics are arranged as sequential frames with the harmonics of a given frame having a pitch period that may or may not be the same as the pitch period of another frame. According to the decoding method, data arrays respectively containing amplitude data and phase data of the harmonics are zero-padded to provide the arrays with a pre-set number of elements. Inverse orthogonal tarnsformation of the data arrays produces time domain information used to generate a time domain waveform signal for restoring the encoded speech signals. The different pitch periods of the frames are normalized to each other either by smooth (continuous) or acute (discontinuous) interpolation depending on the degree of change in the pitch period between the frames.

The ventilatory response of the human respiratory system to sine waves of alveolar carbon dioxide and hypoxia.

Abstract: Sine waves of alveolar CO2 at constant high alveolar O2, and sine waves of alveolar hypoxia (1/(PA, O2 -C), C congruent to 32 torr) at constant alveolar CO2 have been administered to three subjects in each case. Sine waves of six different periods were studied, ranging between 900 and 30 s for the CO2 sine waves and 300 and 20 s for the hypoxic sine waves. The sinusoidal variations in ventilation produced by these manoeuvres, expressed as amplitudes and phase shifts, were compared with values predicted from the dynamic responses to alveolar steps of gas tension already to be found in the literature. For the CO2 sine waves, the amplitudes of response agreed well with those predicted at the higher frequencies, but were less than predicted at the lower frequencies. For the hypoxic sine waves, the amplitude of response varied less with frequency than was predicted. For both the CO2 and the hypoxic sine waves, the phase shift of response was less than expected at the higher frequencies. An attempt was made to fit parameters to a simple model, based on the wash-in and wash-out of respiratory gases into and out of a tissue compartment, and used in the literature for describing the responses to step changes. No satisfactory fit was found. It is concluded that the simple model is unsatisfactory by itself for describing the responses to sinusoidal chemical stimulation; features additional to those included in the model are required to explain fully the responses seen. The possibilities for chemoreception at the higher frequencies are discussed in the light of the low phase shifts.

Power supply control

Abstract: According to a first aspect, an uninterruptable power supply is provided. In one example, the uninterruptable power supply comprises a controller configured to provide a first current reference signal, the first current reference signal having a periodic waveform including a first half period and a second half period, each half period having a period end, the waveform comprising a substantially rectified sine wave modified such that a value of the rectified sine wave is equal to zero for a predetermined period of time prior to the period end of the second half period, a positive current loop control circuit configured to receive the first current reference signal and provide an output signal to the positive boost circuit, and a negative current loop control circuit configured to provide an output signal to a negative boost circuit.

Frequency-based BIST for analog circuit testing

Abstract: In this paper we propose a configuration for a VLSI analog sine wave generator with an appropriate frequency BIST. The generator is used for testing circuits that require sinusoidal input signals with a variable frequency as an input stimulus. The detectors indicate any deviation of the frequency input signal from the nominal value /spl plusmn//spl epsiv/. A sine wave generator and two different BISTs are proposed: the defection and translation (DandT) T-BIST approach and the frequency-counter BIST approach. Some experimental results are also presented.

AC amplifier with automatic DC compensation

Abstract: An AC power amplifier (50) with a pair of push-pull transistors (Q1, Q2) driving opposite sides (36, 38) of the primary winding of an output transformer (T1) controlled by a pair of variable duty cycle, pulse width modulated width trains (A, B) generated on the output of a pulse width modulator (26) controlled, in turn, through means of a wave shaping feedback system to cause the AC output at the secondary winding (20) to track the output of a precision reference sine wave oscillator (12) and through means of another feedback system for automatic DC compensation including a pair of CMOS analog switches respectively driven by the two pulse width modulated pulse trains (A on 28, B on 30) to produce a pair of feedback signals. A junction (58) couples the pair of feedback signals to form a composite feedback signal and an error amplifier (14) also used in the wave shaping feedback system, responds to the composite feedback signal to balance the duty cycles of the pair of drive signals to reduce the introduction of DC to the output transformer (T1).