Spectral analysis belongs to widely used method frequency spectrum of ECG signal instead of usual analysis for biomedical data exploration. In order to interpret based on cardiotachogram (RR interval sequences) derived spectrum correctly, prior knowledge how various from measured ECG. phenomena affect the spectrum of analyzed signal is desirable. Spectrum ofECG signal is affected by waveform component shapes, their time positions within cardiac . cycle as well as by regularity of heart period. This paper 2 Signal Models deals with effect of heart rate variability on ECG signal Impulse sequence, whose parameters are random spectrum. Three representations are proposed to model variables, is called a random impulse process. These variable heart timing in the case of normal sinus rhythm impulse processes can be divided into two classes in (pulse process with time jitter, random inter-pulse interval dependency on statistic attributes of the impulse formation: and integral pulse frequency modulation model).Properties of corresponding spectra are theoretically a Pulse process with time jitter studied and compared with real-world signals from * Pulse process with random interbeat interval PhysioBank data archive.(for ECG) Random impulse process is described by various parameters, which can be stochastic. Impulse sequences Keywords with different properties are analyzed on the basis of these EGG spectrum, heart rate variability, random pulse parameters. In the next, we consider only sequences with process, integral pulse frequency modulation model. constant width and amplitude of the impulse. Pulse Process with Time Jitter

No abstract

Measurement ofvarious properties is the way to mechanical construction. In most cases, desired are determine, whether the measured device is useful for our omnidirectional and bi-directional characteristic. By their specific purposes, or it is not. This paper deals with the combination there may arise cardioid and hypercardioid measurement of microphone properties, concretely the characteristic, or narrow-directional, so called acoustic directional characteristic, which indicates how sensitive it shotguns [1] [3] (See Fig. 1). is to sounds arriving at diferent angles about its central a ['] axis. The goal was to design and realize a full automatic 33 303 30. measurement workplace, develop a method of controlling , the acoustic signal source, transfer the measured data to the personal computer for post-processing and set A[dB]A [dB]