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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
phase noise frequency variation in a carrier signal that appears as energy at frequencies other than the carrier frequency. phase only binary filter transmission or reflection phase plate in which neighboring regions differ in phase shift by pi radians. phase parameter complex parameter representing corrections to the gain and phase of a Gaussian beam. phase plane a two-dimensional state space. See also state space. phase plate transparent medium that introduces different phase shifts to different transverse regions of an optical wave for the purpose of introducing or reducing phase or amplitude structure on the wave; often having only two phase shift values differing by . phase portrait many different trajectories of a second-order dynamical system plotted in the phase plane. phase response the way in which a system alters the phase of an input sinusoid. phase ripple the variation in phase response across the operating bandwidth of an optical or electrical device.
The structure of common music technology systems
Published in Kirk Ross, Hunt Andy, Digital Sound Processing for Music and Multimedia, 2013
The analysis presented so far has been mainly concerned with the magnitude response of a digital filter. For a phase response, we add the angles such as θ1 and θ2 in Figure 5.17. This is because they appear directly in the exponent after the ‘j’, and we add exponents when we multiply exponentials. Similarly we subtract the phases of any terms appearing in the denominator of the transfer function, since dividing by such numbers implies subtracting the exponents. If we plot the results against frequency, we have the phase response. In Equation 5.13 we should take account of the phases of the terms z.z (z2) in this way, if we wish to know the phase response for the filter in Figure 5.14.
Loudspeaker measurements
Published in John Borwick, Loudspeaker and Headphone Handbook, 2012
As has been said, the amplitude response does not totally define the system's performance. The corresponding phase response is required and may be measured, e.g. in the simple way illustrated in Fig. 12.7(a) using a separate phase meter. The measured phase response consists of the phase shift due to the loudspeaker under test plus additional phase rotations due to the time delay between the loudspeaker and the microphone. A delay element in the measuring chain is usually employed to eliminate this additional phase shift so that the phase shift due to the loudspeaker alone is displayed. Alternatively, a more convenient technique known as synchronous detection can be employed.
Heuristic Topology for Designing Reconfigurable Balun Active Filter for Frequency, Bandwidth and Power Division Ratio
Published in IETE Journal of Research, 2023
Shikha Swaroop Sharma, Anjini Kumar Tiwary
Tunability in PDR ranges from 2.5:1 to 7.31:1 across 13% fractional bandwidth. This, however, disturbs the magnitude and phase balance but, in turn, helps in increasing power handling capability. Changing the bias changes the impedance levels at the input and output of the amplifier. Since the amplifier is coupled to the second and third sections of the balun filter, its input loads the second section and output loads the third section. As change in bias point causes a change in loading effect on the second and third sections which, in turn, change the frequency of resonance of the active filter. Two things are achieved at the same time, firstly by changing the load through changing the bias, frequency, bandwidth, PDR re-configurability is achieved and secondly amplifier gain compensates for passive balun filter loss. Under biased conditions the output response loses the balun characteristics and gives filtering response with bias-dependent re-configurability. The phase response of active balun filter is given in Figure 8. The phase difference is not 180° between the two output ports. The amplitudes of the signal at two output ports are also found to be different. Figure 9 shows frequency responses at port 2 and 3 of the active filter are shifted and not showing equal amplitude of the transmission gains, i.e. dB|S21| ≠ dB|S31|. Note that, in the presence of amplifier at all bias point, the circuit does not behave like a balun but has filtering properties intact.
Measurement of the dynamic temperature response of electrocaloric effect in solid ferroelectric materials via thermoreflectance
Published in Phase Transitions, 2023
Layla Farhat, Mathieu Bardoux, Stephane Longuemart, Benoit Duponchel, Ziad Herro, Abdelhak Hadj Sahraoui
In this work, we have adapted this technique to measure directly the electrocaloric effect: the pump laser beam was replaced by an alternating electric field of frequency f, which is applied through our EC material to induce the EC effect (Figure 1). The applied electric field induces the temperature variation inside our EC sample, this temperature variation causes a variation in the reflectivity of the surface of the EC material. To probe the sample’s surface a laser (MRL III 660R) emitting in the red with a wavelength equal to 660 nm is used. Its power at the output of the cavity is 50 mW. A gold top electrode is considered because the gold reflects the red probe beam with a reflectance coefficient of approximately 98%. The use of this electrode (homogeneously opaque) ensures very good reproducibility of the experimental measurements. A lock-in amplifier (SR 7280), synchronized to the same frequency of the applied field, extracts the amplitude V(t) and the phase response of the reflected probe signal collected by the photodiode. These quantities are related to the EC properties of the sample. The EC temperature variation ΔT is related to the voltage signal V(t) measured by the lock-in amplifier by the following relation [20]:
Low Complexity Joint PAPR Reduction and Demodulation Technique for OFDM Systems
Published in IETE Journal of Research, 2022
V. P. Thafasal Ijyas, Mohammed I. Al-Rayif
The system anticipates non-linear distortion of the transmitted signal by the transfer characteristic of the power amplifier. In this work, we have considered a solid-state power amplifier (SSPA) with the following amplitude/amplitude (AM/AM) and amplitude/phase (AM/PM) characteristics [31]. is the amplitude of the thresholded signal, is the amplifier amplitude response and is the phase response. is the output saturation amplitude, is defined as the smoothness control coefficient of the SSPA and is related to the linearity of the SSPA. Larger the value of , the more linear will be the transfer characteristic of the amplifier. The output of the amplifier is