Analog domains

Although a detection system that could acquire the counting and analog-domain signals simultaneously would improve the dynamic range and utility of spot... 

CLASS I Enzyme only With tRNA substrate analog domains... 

Because the chief electrochemical variables are all analog quantities (at least in the ranges of normal interest), our first concerns are with circuitry for controlling and measuring voltages, currents, and charges in the analog domain. The circuit elements best suited to these jobs are operational amplifiers. We must explore their properties before we can understand the way in which the amplifiers are assembled into instruments. 

Information in the analog domain is encoded as the magnitude of one of the electrical quantities — voliage, current, charge, or power. Tlie.se quantities are contin-... 

FIGURE 4-1 Detoclor response versus time plots for the same signal in (a) an analog domain and (b) the digital domain. 

TTie observation that kinases generally have a bilobal structure roughly similar to that found in hexokinase has led to the suggestion that analogous domain motions are a common feature of this class of enzymes. 

The modes of encoding information as electrical quantities can be subdivided into analog domains, lime domains, and the digital domain, as illustrated in the bottom half of the circular map in Figure 1-2. Note that the digital domain is not only composed of electrical signals but also includes one nonelectrical representation, because numbers presented on any type of display convey digital information. 

The time between successive LO to HI transitions is called the period, and the time between a LO to HI and a HI to LO transition is called the pulse width. Devices such as voltage-to-frequency converters and frequency-to-voltage converters may be used to convert time-domain signals to analog-domain signals and vice versa. These and other such data-domain converters are discussed in Chapters 2-4 as a part of our treatment of electronic devices and will be referred to in other contexts throughout this book. 

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