Ch Frequency Response (802.11a/g/j/p OFDM)

Menu Path: Trace > Data > Channel X > Ch Frequency Response where X is the selected channel.

When 802.11a/g/j/p 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. Demodulation is enabled, Ch Frequency Response is the measured equalizer frequency response for the burst, based on analyzing the preamble of the burst. It contains one complex value for each subcarrier, plus an interpolated value at the middle unused subcarrier (a total of 53 values).

This is similar to, but not the same as, the Digital Demodulation channel frequency response. The differences are:

• Digital Demodulation computes this by comparing the IQ Meas Time and IQ Ref Time data, while 802.11a/g/j/p OFDM digital demodulation computes it from the preamble of the burst.

• Digital Demodulation typically uses a running average to average multiple scans when computing the equalizer frequency response. OFDM demodulation does not average, but computes a new equalizer response for each burst.

• The equalization filter is inherent to 802.11a/g/j/p OFDM Demodulation, it cannot be enabled/disabled like in Digital Demodulation.

See Also

Eq Impulse Response (802.11a/g/j/p OFDM)

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