Eq Impulse Response (MB-OFDM)

Comp Eq Impulse Response shows the impulse response of the equalization filter. The Eq Impulse Response is computed using both the Channel Estimation Sequence portion of the preamble and the data symbols.

The composite result is computed only when performing FFI analysis (TFCs 5 - 7) or TFI/TFI2 analysis when Frequency Hopping Analysis is set to Force FFI. For hopped signals, there will be no results and the error message DATA? will display.

The result length will be four times the FFT Fast Fourier Transform: A mathematical operation performed on a time-domain signal to yield the individual spectral components that constitute the signal. See Spectrum. length so a total of 512 points.

This is similar to, but not the same as, the Digital Demod Eq Impulse Response. The differences are:

Digital Demod computes this by comparing the IQ Meas Time and IQ Ref Time data, while MB-OFDM demodulation computes it from the preamble/data of the burst.
Digital Demod typically uses a running average to average multiple scans when computing the equalizer impulse response. MB-OFDM demodulation does not average but computes a new equalizer response for each burst.
The equalization filter is inherent to MB-OFDM demodulation, it cannot be enabled/disabled like Digital Demod.