Frequency Conversion with Mixer

A mixer is a device that outputs the result of multiplying two input signals.

The resulting output is a combined signal containing both the sum and difference of the two input frequencies.

Both the sum and difference frequency components preserve all the information of the original input signals.

1. Down conversion

In down-conversion, a filter is used to extract the difference frequency, which is referred to as the beat frequency.

This frequency forms the baseband signal, allowing RF/high-frequency information to be easily processed at a lower frequency.

2. IQ Decomposition for Phase Information Preservation

Radar sensors generate I (In-phase) and Q (Quadrature) signals by mixing the received signal with two reference signals shifted by 90°.

This IQ pair is essential because it preserves the phase information of the received signal.

By using these components, the radar can accurately calculate the target’s range and velocity while effectively filtering out unwanted noise.