Part 2 presents all the viable sensor technologies required to exploit the wide range of unknown modulations and signals under test. It starts with explanations of the sensor technologies, and how they came to be to meet certain measurement needs. Sensor choices range from the venerable thermistor to the innovative thermocouple to more recent improvements in diode sensors. In particular, clever variations of diode combinations are presented, which achieve ultra-wide dynamic range and square-law detection for complex modulations. New instrumentation technologies, which are underpinned with powerful computational processors, achieve new data performance.