Selectivity / Channel Rejection

1. Selectivity / Channel Rejection • Gives a measure of how good the receiver is at handling interference Desired signal / Interferer Power Alternate channel rejection/ Selectivity [dB] Adjacent channel rejection [dB] Co-channel rejection [dB] Frequency Channel separation Channel separation

2. Blocking Desired signal / Interferer Power Frequency Frequency Offset • Gives a measure of how good the receiver is at handling interference from a source further away in frequency

3. Receiver Example Desired signal / WLAN Power Frequency 5 MHz Chip A Chip B Sensitivity: -100 dbm -97 dBm Blocking: 27 dB +/- 5 MHz offset 55 dB +/- 5 MHz offset Case 1: The power from the WLAN is –80 dBm. Receiver A can receive a –100 dBm signal. Receiver B can receive a –97 dBm signal. No degradation in receiver sensitivity.

4. Receiver Example 2 Desired signal / WLAN Power Frequency 5 MHz Chip A Chip B Sensitivity: -100 dbm -97 dBm Blocking: 27 dB +/- 5 MHz offset 55 dB +/- 5 MHz offset Case 2: The power from the WLAN is –40 dBm. Receiver A can receive a -40-27 = -67 dBm signal. Receiver B can receive a -40-55 = -95 dBm signal. Receiver B have 27 dB better receiver sensitivity.