Frequency deviation

A phase modulation can also be expressed as frequency modulation. The corresponding frequency deviation is the time derivative of the modulated phase angle (Pm t). According to the basic relationships Acarrier frequency fg, commonly known as the Doppler frequency shift... 

As a reference, the position of absorption of the carbonyl group in a saturated acyclic ketone which occurs at 1720 cm "1 is regarded as the normal frequency. Deviation from this absorption position may be correlated with the influence of electronic and steric effects which arise from the nature of the substituents (R and X) attached to the carbonyl group. 

The maximum instantaneous frequency deviation A (Umax is therefore given by A (i)max I(i>m. When the modulation index/is nonzero, side frequencies occur above and below the carrier 00c, and the number of side frequencies increases with increasing I. 

When the frequency deviation, t/, is smaller than the value y(n9Sn)B2/2it, the 119Sn satellite lines are broadened a little [see Fig. l(e-g)]. 

For smaller hydro power systems, such a solution is considered to be complex and additionally a danger exists of rapid control valve movement introducing damaging surge pressure waves in the pipelines or instability in the overall control system (Roberts, 2002). A preferable solution to maintain frequency close to its nominal value is the utilisation of load control. For the implementation of this scheme, secondary or even dump controllable loads are switched on and off, according to frequency-deviation measurements. 

Although experiments are most directly expressed in terms of the oscillator coordinate q(r), the quantity of physical relevance is the instantaneous oscillator frequency deviation from the mean frequency, w(t) = oo(t) — (co). This frequency deviation is the direct consequence of time-dependent forces exerted on the oscillator by its environment. At a semiclassical level, the FID correlation function is related to the time-dependent frequency by... 

The H local vibrational mode at 3096 cm has been assigned to N-H centers. This assignment is consistent with a recent theoretical investigation by Van de Walle who calculated a vibrational frequency of approximately 3100 cm for the N-H center. It is interesting to note that this frequency deviates by about 10 % from the value observed for the N-H vibration in ammonia molecules. 

For the individual vibrational modes or force constants an equivalent trend is indicated. For example, the ground state Sq and the excited state Tj frequencies of Pt(2-thpy)2 are still clearly different (see the Figs. 14 and 15 and Table 7). However, for [Os(bpy)3] with a typical MLCT state, ground state frequencies deviate from those of the excited state only by 2 cm, as far as they have been determined (see Ref. [22, p. 228]). 

For the residual coupling H1 to be negligible we require that the weighted frequency deviation in (4.25) be small, or more precisely that... 

Let us next turn to the low frequency behaviour. oi(e I a) shows a weak shoulder, but drops effectively to zero apart from a molecular line at 2200 cm /the C-N stretch in the TCNQ/. (e c is close to simple Drude behaviour in the near IR, but at lower frequencies deviations prevail, as for example the dip at 1500 cm and the apparent decrease below 900 cm With reasonable extrapolation procedures for 0[Pg.352]

Studies showed that a BESS on the MP L system could (i) help stabilize and improve the power quality of the system, i.e., reduce voltage and frequency deviations (ii) reduce reliance on the diesel generator, and thus realize attendant savings in fuel-related costs. Subsequently, the GE-GNB alliance (see Section 10.5.8) provided a suitable, 1.6-MVA (10s)/1.0-MW (continuous) BESS, which was interconnected at a 12.47-kV sub-station. Construction began in April 1996, was completed in December 1996, and the BESS has been operational since February... 

Because of the parallel capacitance the zero phase frequency deviates from the series resonance frequency, Eq. 14, as discussed in Sect. 3.1.1, therefore series resonance oscillators oscillate at a frequency/osc fs- The series resonance frequency/s is not accessible with standard oscillator concepts without compensation of the parallel capacitance, Cq. The phase of a quartz crystal with compensation of Co becomes (pm = where again... 

The use of feedback to provide frequency control of the klystron has the obvious advantage that the usable range of frequency deviation is much larger. Also the real component of electron conductivity encountered at high pressures (and which changes the cavity Q) can have an effect only on the error signal (—5% ) in the feedback loop rather than upon the whole signal as in the case of no feedback. 

The underlying origin of the multitude of many-body lines in the emission spectrum from quantmn-confined systems is that a recombination is accompanied by shakeup processes whose number increases as the frequency deviates from the Fermi edge. The theoretical value of the dimensionless... 

Additionally, Biot (1956a, b) introduced a complex correction function (F) which accounts for a frequency-dependent viscous flow resistance (r /K). In fact, while the assumption of an ideal Poiseuille flow is valid for lower frequencies, deviations of this law occnr at higher frequencies. For short wavelengths the inflnence of pore flnid viscosity confines to a thin skin depth close to the sediment frame, so that the pore fluid seems to be less viscous. To take these effects into account the complex fnnction (F) modifies the viscous flow resistance (p/K) as a fnnction of pore size, pore flnid density, viscosity and freqnency. A complete definition of (F) can be fonnd in Stoll (1989). 

All of these phase shifts are approximately linear in frequency for moderate frequency deviation. For example, it was pointed out in II.A.2. that the phase shift due to finite Hj is quite linear for offsets up to vH. Therefore, a linear phase correction of the form A=(Au)/27i)+B, implemented by software, is quite effective. 

A better relative agreement is found for the C-0 vibration mode, for which computed frequencies deviate from experimental results by about 6% only (Tables 3 4). It was noted earlier that the C-0 stretching frequency is pretty much dependent on the CO coverage, the actual value for bridge chemisorption ranging from 1898 cm" (6 = 0.07) to 1942 cm" (6 = 1.00) according to Yoshioka et al. [51], Our present molecular models involve a unique CO molecule chemisorbed on Pd(lOO), and is thus more likely to describe a situation of low CO coverage, in which there is no side CO/... 

Figure 3.11b Comparison of the spectral linewidth and maximum deviation of the FM source frequency. The frequency deviation at the MMW frequency would be typically 250 kHz and linewidth HWHM > 1-2 MHz. The carrier sweeps between the deviation limits at the source modulation rate, 1 kHz typically...

Dilute solutions of the coating materials were prepared In chloroform. These solutions were then aspirated using an airbrush to generate a finely dispersed aerosol, which was deposited on one side (l.e. one delay line) of the dual SAW device. The film thicknesses were estimated using the first term from Equation 1, neglecting elastic effects. Estimated film thicknesses were on the order of 50 - 100 nm. The other delay line remained uncoated, acting as a reference to correct for frequency deviations due to fluctuations In ambient temperature and pressure. 

The turning to impedance spectroscopy, polymer-salt systems should exhibit semicircles in the Z - Z plane. Figures 19 and 20 provide examples that refer to mixtures of polymer and LiClO. We recognize that in the range of low frequencies deviations from the circle occur. 

The most common argument is simply that when the distance between array and groundplane is one-quarter electrical wavelength, the signals from the array and the groundplane will be in phase in the forward direction (see also Section 6.12.4). Thus, it is concluded that this must constitute the optimum And when the frequency deviates, it goes downhill that is we will lose bandwidth. 

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