Home
Contact Us
Can't you choose the video glasses you need?
Contact Us
!
Zune Video Glasses
The result of this process can be inside Zune Video Glasses represented to taking as constellation points the i, q-area, which represents the different values, the I and Q can. Table 7.2 gives the main characteristics and the designation of some quadrature modulation drafts as function the number of the points for each i-and of the q-signals. Tables 7,4 and 7,5 show and/or the constellations of QPSK modulation (quadrature phase shift keying or 4-QAM) and 64-QAM. These illustrations do not represent the situation at the exit of the modulator, where each point is differentiated Zune Video Glasses well from its neighbours, thus it give an ambiguity regarding the symbol value on this level. The breakdownsignaling relationship considering, which is reached on the receiving side, 2 bits/symbol (QPSK modulation) was found, over to be practical maximum and therefore the best spectral efficiency, for transmissions over Satelitte. In case of the cable the breakdownsignaling relationship is much more highly and a modulation 64-QAM (6 bits/symbol), approximately can three times more efficient in the spectral expressions, be used; American use 256-QAM (8 bits/symbol) of the standards even. Table 7.7 illustrates the effect of the noises on the QPSK constellation recovered at the exit of the demodulator of the receiver in case of a loud Satellitenaufnahme. Table 7.8 shows the case of a cable admission of a signal 64-QAM with a low breakdownsignaling relationship (the order DBs 23). It is conceivable that, over a certain noise level, the demodulator is not capable, with security, one point in the constellation of differentiating of its neighbours; there is the ambiguity, those the symbol surrounds receiving and therefore a possible disturbance. Zune Video Glasses That more largely the number of points in the constellation, lower becomes the acceptable noise level is you, there the points is closer with one another.]] > those it prevents 90 (the hoisting engine resumption system can lock itself in four different conditions of the phase 124) that the receiver synchronizes, as long as the demodulation phase is wrong. In case of the QAM modulation, which is used for cables, is avoided this problem by the use of a differenzialen modulation for the two MSBs of symbol: the condition of the MSB of I and of Q corresponds to a phase changes you and not to an absolute phase state, which the receiver in any of the four possible closed conditions (the constellation of the LSBs, which is identical in the four quadrants) to function leaves. Table 7.3 represents the truth table used for differenziale coding of the MSB of the I and to Q-Modulationssignale, around the QAM to produce assigned in DVB-C. In case of (Nichtdifferenzial) the QPSK modulation, which is used for satellites, „from Synchrounisierung the “information can be used, in order to change (until three times) the phase relation between the recovered hoisting engine and the received signal to Synchrounisierung is reached.]] >
Brands
heregoesmyvu
Copyright © , TheVideoGlasses.com. All rights reserved.
Copyright ® TheVideoGlasses.com All rights reserved.
1
2
3
4
propecia
Zune Video Glasses
