The receiver pulls the signal from free space, removes the information from the carrier and outputs the original information. The figure illustrates a single-conversion superset AM receiver. While receiver topologies vary widely, all involve several stages to affect the reception and recovery process. The RF signal is recovered from free space by the antenna. The signal is amplified to a more usable level and then fed into a device called a mixer. The mixer takes this incoming signal and combines it with an on-board frequency source called a local oscillator. This converts the signal to a new lower frequency called the Intermediate Frequency or IF for short. The detector then strips out the IF frequency and recovers the original information.