What device is utilized to create new frequencies from two applied signals?

The device that is utilized to create new frequencies from two applied signals is a mixer. A mixer combines two different frequency signals, typically a radio frequency (RF) signal and a local oscillator signal, to produce new frequencies known as intermediate frequencies (IF). This process involves mathematical operations in which the output frequencies are the sum and difference of the input frequencies. For example, if one signal has a frequency of 100 MHz and the other has a local oscillator frequency of 95 MHz, the mixer will produce frequencies of 5 MHz and 195 MHz.

In contrast, a modulator is responsible for varying a carrier signal to encode information, rather than creating new frequencies. An AM receiver is used for demodulating the amplitudes of signals, and an amplifier increases the power of a signal without altering its frequency content. Hence, the mixer is the correct answer as it directly relates to the creation of new frequencies through the combination of different input signals.