2. Modulation rate(调制速率) Description: When signal encoding techniques are used, a distinction needs to be made between data rate(expressed in bits per second) and modulation rate (expressed in baud). The data rate, or bit rate, is R-1/Tb, where Tb is bit duration The modulation rate is the rate at which signal elements are generated Consider for example, Manchester encoding. The minimum size signal element is a pulse of one-half the duration of a bit interval. For a string of all binary zeros or all binary ones, a continuous stream of such pulses is generated. Hence the maximum modulation rate for manchester is d=2 /Tb. This situation is illustrated in Figure 5.5(E6), which shows the transmission of a stream of binary ls at a rate of MBps using nrzi and manchester. In general, D=R/b where D= modulation rate. baud R=data rate. bps b=number of bits per signal element10 2. Modulation Rate（调制速率）  Description: When signal encoding techniques are used, a distinction needs to be made between data rate (expressed in bits per second) and modulation rate (expressed in baud). The data rate, or bit rate, is R=1/Tb, where Tb is bit duration. The modulation rate is the rate at which signal elements are generated. Consider, for example, Manchester encoding. The minimum size signal element is a pulse of one-half the duration of a bit interval. For a string of all binary zeros or all binary ones, a continuous stream of such pulses is generated. Hence the maximum modulation rate for Manchester is D=2/Tb. This situation is illustrated in Figure 5.5（E6）, which shows the transmission of a stream of binary 1s at a rate of 1Mbps using NRZI and Manchester. In general, D=R/b. where  D = modulation rate, baud  R = data rate, bps  b = number of bits per signal element