I/Q RECEIVER/DOWNCONVERTER BLOCK DIAGRAM

This Block diagram depicts a 2-channel downconversion receiver front-end (I/Q demodulation), typically used in communication systems (e.g., satellite/radio reception):

1. Signal Reception:

• The antenna captures RF signals, which pass through a Preselector (filters unwanted frequencies) and a LNA (Low Noise Amplifier, boosts weak signals while minimizing noise).

2. I/Q Demodulation:

• A 90° Hybrid splits the LO (Local Oscillator) signal into two paths: one in-phase (0°) and one quadrature (90°).

• Two Mixers combine the amplified RF signal with the 0°/90° LO signals, converting the RF signal to a lower intermediate frequency (IF).

3. Signal Conditioning:

• Bandpass Filters (DC to 2 MHz) remove mixing artifacts.

• AGC Amplifiers (Automatic Gain Control) stabilize signal levels, ensuring consistent output for the I (in-phase) and Q (quadrature) channels.

Key function: Converts RF signals to baseband I/Q signals for digital processing, with 90° LO phase separation enabling coherent demodulation.