IQdemodulointi

IQdemodulointi, often referred to as I/Q demodulation, is a fundamental process in digital radio communication. It involves separating a complex radio signal into its in-phase (I) and quadrature (Q) components. These components represent the amplitude and phase information of the original radio wave, allowing for the recovery of the transmitted data.

The process begins with a radio frequency (RF) signal that has been modulated with data. This signal is typically mixed with two local oscillator signals that are 90 degrees out of phase with each other. One local oscillator signal is in phase with the incoming RF signal, producing the in-phase component. The other, shifted by 90 degrees, produces the quadrature component. These mixed signals are then typically passed through low-pass filters to remove unwanted high-frequency components, leaving the baseband I and Q signals.

These I and Q baseband signals are then digitized by analog-to-digital converters (ADCs). Once in digital form, a digital demodulator uses these I and Q values to reconstruct the original data stream. This technique is crucial for many modern modulation schemes, such as Quadrature Amplitude Modulation (QAM) and Phase-Shift Keying (PSK), which encode information in both the amplitude and phase of the carrier wave. The ability to separate and process the I and Q components is essential for efficient and accurate data recovery in wireless systems.