EVM Measurement per 3GPP TS 36.104: Error Vector Magnitude is the primary modulation quality metric for LTE transmitters. The FDD-LTE option demodulates the signal, recovers the I/Q constellation, and computes EVM per the 3GPP specification—including the correct reference signal structure and equalization. This is different from generic VSA EVM measurement because the option understands the LTE frame structure: it knows where CRS (Cell-specific Reference Signals), PSS/SSS (synchronization signals), and PDSCH/PUSCH data are, and measures each correctly.
Per-Resource-Block Analysis: LTE allocates spectrum in resource blocks (180 kHz each). The FDD-LTE option reports EVM, power, and modulation type per resource block—revealing problems like edge-of-band roll-off, frequency-selective impairments, or incorrect power allocation across the channel. This granularity is essential during PA development and base station commissioning.
Downlink and Uplink Testing: The option supports both downlink (eNodeB transmission) and uplink (UE transmission) demodulation. Downlink analysis covers CRS, PSS, SSS, PCFICH, PDCCH, PHICH, PBCH, and PDSCH channels. Uplink covers PUCCH, PUSCH, and SRS. This dual capability means one option handles both base station manufacturing test and UE development.
ACLR Testing: Adjacent Channel Leakage Ratio is the critical spectral emission measurement for LTE transmitters. While the AMK option can measure ACPR for any signal, the FDD-LTE option provides standards-compliant ACLR measurement with the correct 3GPP channel and offset bandwidth definitions—including E-UTRA and UTRA ACLR values required for regulatory compliance.