Lab 8: Frequency-Shift Keying

In this lab, students will learn about frequency-shift keying. In frequency-shift keying (FSK), a 1 is represented by a tone at a specific frequency, known traditionally as the “mark” frequency, while a 0 is represented by a tone at a different frequency, known as the “space” frequency. FSK owes part of its popularity to the fact that a tone is always being transmitted, even when the source generates a long string of zeros. This makes it easy for the receiver to distinguish between a transmitter that is idling and a transmitter that has stopped transmitting. FSK also has the property that the transmitted signal has a constant amplitude. This allows a very efficient nonlinear power amplifier to be used for transmission, a very important consideration when the transmitter is battery-powered.