Symbol rate

As the number of symbols increases, more data bits are transmitted per symbol. For example, 64-QAM is a QAM scheme with 64 symbols, and 256-QAM is a scheme with 256 symbols. 256-QAM conveys 8 bits per symbol (as 256 = 28), so achieving twice the data rate of 16-QAM for the same symbol rate.

In theory, bandwidth is related to data rate by: 1) Nyquist formula: data rate = 2 * bandwidth * log2 (M) ; where M is the modulation level (eg., M=4 for QPSK ). 2) Shannon formula: data rate = bandwidth * log2(1+SNR) ; where SNR is the signal to niose ratio.

Note 3: The data signaling rate (DSR) in a cable is given by the relation DSR = Σ(log) 2n)/T i summed from i = 1 to i = m where DSR is the data signaling rate, m is the number of parallel channels in the cable, n i is the number of significant conditions of the modulation in the i-th channel, and T i is the unit …

In digital modulation, the Symbol Rate determines the rate (frequency) at which symbols occur . A symbol may consist of one or more bits as determined by the modulation format. For example, in a BPSK. system, each symbol represents 1 bit; in a QPSKQuadrature phase shift keying system, each symbol represents 2 bits.