ANALOG DATA, DIGITAL SIGNALS
In this section we examine the process of transforming analog data into digital signals.
Strictly speaking, it might be more correct to refer to this as a process of converting
analog data into digital data; this process is known as digitization. Once
analog data have been converted into digital data, a number of things can happen.
The three most common are as follows:
1. The digital data can be transmitted using NRZ-L.2 In this case, we have in fact
gone directly from analog data to a digital signal.
2. The digital data can be encoded as a digital signal using a code other than NRZL.
Thus an extra step is required. .
3. The digital data can be converted into an analog signal, using one of the modulation
techniques discussed in Section 6.2.
This last, seemingly curious, procedure is illustrated in Figure 6.14, which
shows voice data that are digitized and then converted to an analog ASK signal.
In this section we examine the process of transforming analog data into digital signals.
Strictly speaking, it might be more correct to refer to this as a process of converting
analog data into digital data; this process is known as digitization. Once
analog data have been converted into digital data, a number of things can happen.
The three most common are as follows:
1. The digital data can be transmitted using NRZ-L.2 In this case, we have in fact
gone directly from analog data to a digital signal.
2. The digital data can be encoded as a digital signal using a code other than NRZL.
Thus an extra step is required. .
3. The digital data can be converted into an analog signal, using one of the modulation
techniques discussed in Section 6.2.
This last, seemingly curious, procedure is illustrated in Figure 6.14, which
shows voice data that are digitized and then converted to an analog ASK signal.
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