Eq Chan Freq Resp (LTE)
shows the channel frequency response calculated from the reference signal (C-RS Cell-specific RS for downlink and DM-RS DeModulation Reference Signal (LTE) for uplink) using the time data in the Search Time trace (capture length primarily determined by Result Length).
For downlink signals, is calculated from the reference C-RS/Rx path (determined by the reference measurement channel and the reference C-RS port). To view the equalization frequency response for all C-RS/Rx paths simultaneously, see MIMO Eq Chan Freq Resp.
The Equalizer Training settings determine data that is shown on the trace. When is set to , the trace will show a flat line indicating that no equalization is performed. When is set to , the trace will show the equalization frequency response calculated from the reference signal. When is selected, the trace will show the equalization frequency response calculated from the reference signal and the data subcarriers (PDSCH Physical Downlink Shared Channel for downlink and PUSCH Physical Uplink Shared Channel for uplink). Also, the moving average filter setting affects the equalizer frequency response and thus affects the as well.
This trace is always calculated from an 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. symbol 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. taken from the center of the cyclic prefix. This is different from most Demod Trace Data and Layer Trace Data, which use the Symbol Timing Adjust parameter to determine the location of the symbol FFT. See the Symbol Timing Adjust topic for more information.
This trace is affected by Averaging.
The Equalizer Training parameter determines whether the equalization is applied to the signal.
can be used to view the frequency response of the transmitter's filters when the transmitter is connected directly to the measurement hardware.
is affected by the Normalize Chan. Freq. Resp. parameter. is always shown with an average per-subcarrier power gain of 0 dB. When the is selected any phase, frequency, or timing offset in the channel frequency response is removed. When is cleared, any phase, frequency, or timing offset present in the channel frequency response is not removed.
See Also
