The effect of varying constellation size for square and cross M-QAM
has been observed using NMSE and CRLB in Fig.
Many disturbing factors decreasing the quality of the digital channels are proved to be present within the HFC systems, whereas some of them are linked to the topology of the network, and others to the means of mixing the AM-VSB and M-QAM signals and parameters of the optical devices--optical receivers, optical transmitters and optical amplifiers.
q] - the optical modulation index for M-QAM signal; F - the receiving-transmitting link efficiency; M--multiplicity of QAM modulation; T--symbol time of the M-QAM signal; T = 1/B; B is the bandwidth of the channel.
It is clear that the following functions take zero values at every symbol point of high-order M-QAM signals by using the coordinate transformation criterion
And the computational requirements of the proposed algorithm for different high-order M-QAM signals are shown in Table 2.
The computational requirements of the proposed algorithm per weight update for different high-order M-QAM signals M-QAM Multiplications Additions sgn(.
Nevertheless, the presented program allows for drawing up of analysis of systems' performances based on M-PSK and M-QAM manipulations.
M-PSK and M-QAM BER Computation Using Signal-Space Concept // IEEE Transactions on Communications.
Investigation on Noise-stability of the Optical Link by AM-VSB and M-QAM Signals Transmitting in HFC Communication Systems // Electronics and Electrical Engineering.
These micro reflections sometime severely influence the C/N ratio of the M-QAM signals, but an adaptive equalizer offers a promising solution for such digital channel deterioration.
At the HFC networks with jointly transmitting of AM-VSB and M-QAM channels, in the laser diode arise a "clipping" of SCM signal, when (Fig.
2]--the average received signal power in each M-QAM channel; [m.