Mixer and Beat Frequency Signal

A mixer multiplies the received signal with the transmitted (TX) signal,

generating Q/I-mix, sum and difference frequency components that contain the signal information.

I/Q signals are used to preserve both the amplitude and phase of the signal by representing it in complex form.

This allows accurate baseband processing and enables full reconstruction of the original signal without loss of information.

1. Beat Frequency Signal

Among the mixer outputs, the beat frequency signal is suitable for baseband processing,

so the sum frequency component is removed using a low-pass filter.

A programmable gain amplifier (PGA) is used before the ADC

to adjust the signal amplitude, maximizing dynamic range and preventing saturation.

2. Signal Conditioning