Receiver Adjacent Channel Rejection

Definition

Receiver adjacent channel rejection is the measure of how well a receiver can receive the transmitted signal in the presence of a high-level interfering signal in the adjacent channel. It is measured as a frame error ratio (FER) or packet error rate (PER) at specified interferer power levels.

Standards

• IEEE Std 802.11b-1999 16 September 1999 Paragraph 18.4.8.3 Receiver adjacent channel rejection
• IEEE Std 802.11a-1999 16 September 1999 Paragraph 17.3.10.2 Adjacent channel rejection
• ANSI/IEEE Std 802.11 First Edition 1999-00-00 Receiver adjacent channel rejection

Measurement Subtleties

The adjacent channel rejection measurement is very important because it tells you how well your device will perform under real-world conditions. The alternate channel rejection test is very similar to this test.

The test setup, according to the IEEE standards, must have two independent signal sources for the in-band and the adjacent channel signals. The two signal sources cannot be coherent in either phase or frequency.

You will need a signal combiner for the test signals. It is recommended that you use an isolator for each source in order to avoid injection locking.

Test Tools

To perform this measurement, you will need two E4438C vector signal generators, the 89600 vector signal analyzer (VSA), and the advanced design system (ADS), all with the appropriate options.

The ADS software is used to create fully coded WLAN signals, which are downloaded to the E4438C Dual Arb. The first signal generator will act as the primary WLAN signal provider, while the second signal generator provides the interfering signal. The signals are recorded using the 89601A software, and the recordings are ported back into ADS software for PER and FER testing.

Keysight's advanced design software (ADS) directly interfaces to the 89600-analysis software to create a powerful design and analysis tool.