Modulation Scheme (Custom OFDM)

Default: OFDM Orthogonal 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.

Range: OFDM, F-OFDM, FBMC

Modulation Scheme selects the modulation technique to be used in the Custom OFDM demod configuration. The plain OFDM scheme can be extended by using filtering in various ways. The purpose of this filtering is mostly to reduce the out-of-band energy in the signal, so that several signals can be spaced closely together in the frequency domain.

OFDM - The default modulation scheme value. OFDM (Orthogonal Frequency-Division Multiplexing) analysis is done the same as in previous versions of VSA.
F-OFDM - When F-OFDM (Filtered OFDM) is selected, the input signal is expected to have a band-pass filter applied to it to reduce out-of-band energy. The analysis is identical to plain OFDM modulation, but trace results contain “F-OFDM” instead of “OFDM” in the trace titles. You can apply your own custom compensating filter by specifying Arbitrary Coefficients for the multi-carrier filter on the Filter tab.
FBMC - When FBMC (Filter Bank Multi-Carrier) is selected, the input signal has a filter applied to each subcarrier. When the Modulation Scheme is set to FBMC, the Multiple Access Scheme property is not supported and is set to None. In addition, the Guard Interval Per Symbol and Time Gaps properties (on the Format tab) are ignored when doing FBMC analysis.