ion is the ability of a system or part of a system, to respond to a changed requirement or changed condition. ii Scale (scaling) is the expression of the order of magnitude over which the adaptation takes place (the range) and may also comprehend the rate and resolution of the response. iii Context is the amount of observable information available in order for the system itself or some external function to take a decision on the adaptation process. The accuracy of the observation process and the ability of the system to interpret and act on the observed information will have a direct impact on overall system efficiency. The function of the human heart provides a biological example. Our heart rate and blood pressure increases when we run. Our heart rate and blood pressure also increases when we use our observation system (sight, sound, smell, touch and sense of vibration) to perceive potential danger and/or local opportunity. As such, the process of adaptation is both reactive and proactive. The scale in this example ranges from the lowest to highest heart rate. The context is either actual (we have started to run) or predictive (we know we might have to run). Human observation systems in themselves are adaptive. For example, our eyes can adapt to light Making Telecoms Work intensities ranging from small fractions of a lux to over 100 000 lux. This is the scale of the adaptation process. The context, in this example, is the ambient light level. 21.5 Examples of Adaptation in Existing Semiconductor Solutions Many present semiconductor solutions used in cellular phones, consumer and professional electronics products and network devices use adaptation to decrease power drain. In this context, adaptation is based on the ability to change the clock speed (heart rate) and/or voltage (blood pressure) of the system when presented with specific processing tasks (the context). The scale is the highest to lowest clock rate and highest to lowest voltage. The rate of response (milliseconds or microseconds) and accuracy of resp