About 802.11a/g/j/p OFDM Modulation Analysis

89601B7RC (89601B-B7R) 802.11a/g/j/p OFDMOrthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. Modulation Analysis adds Orthogonal Frequency Division Multiplexing demodulation capability to your 89600 Vector Signal Analysis application software. 89601B7RC performs modulation analysis on OFDM modulated signals using standard OFDM formats.

While providing demodulation capabilities for standard OFDM formats, 802.11a/g/j/p OFDM Modulation Analysis also provides the flexibility to measure nonstandard OFDM formats. The VSA's demodulator parameters are user-definable, giving the flexibility to customize the VSA for measuring non-ideal signals. User-definable parameters include subcarrier modulation format and spacing, symbol timing , burst synchronization, and error correction (see 802.11a/g/j/p Demod Properties).

The digital demodulator used in this VSA incorporates advanced technology that does not require external filtering, coherent carrier signals, or symbol-clock timing signals to lock-on to the measured signal. Signal locking requires these parameters to be set properly: center frequency, guard interval, subcarrier spacing, and search length.

Along with the typical digital demodulation measurement results, several additional OFDM unique display formats and numeric error data results enhance data analysis. These include Error Vector Time, Error Vector Spectrum, Common Pilot Error, RMS Error Vector Time, and RMS Error Vector Spectrum trace data (see Available Trace Data. Flexible display scaling and marker functionality help make accurate and quick measurements.

Display measurement data for only one OFDM subcarrier at a time (using the Carrier-to-Analyze parameter) or for selected data regions (using the Measurement Interval and offset parameters). These features provide a tremendous tool for signal analysis and troubleshooting (see Result Length).

The VSA uses the measured signal (called IQ Meas) to generate an ideal signal (called IQ Ref). Many IQ Meas and IQ Ref trace data formats and numeric error trace data are computed and available for data display and analysis. This data can be used to quantify and locate errors in the signal, see About the Symbol Table.

See Also

OFDM Overview

Available Features (802.11a/g/j/p OFDM)

Setting up an 802.11a/g/j/p Measurement

802.11a/g/j/p Demod Properties

About the Symbol Table (802.11a/g/j/p OFDM)

Available Trace Data (802.11a/g/j/p OFDM)