Symbol rate

Each of the four possible phases of carriers represents two bits of data. Thus, there are two bits per symbol. Since the symbol rate for QPSK is half of the bit rate , twice the information can be carried in the same amount of channel bandwidth as compared to binary phase shift keying.

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.