R&S FSL Cable TV Measurements (Option K20)
1300.2519.12 2.79 E-11
Please note that the Echo Pattern can also be measured with the equalizer switched off. As long as
t
here are only few decision errors in the QAM demodulator this will lead to the same echo pattern.
Press the PREVIOUS key twice to go two menu levels up.
Press the Digital TV Settings softkey (see Fig. 2-51).
If the equalizer should get into an instable state (e.g. if the signal was removed), press the
Reset button.
If the equalizer was properly trained and the channel does not change anymore, activate the
Freeze Equalizer option. Freezing the equalizer can speed up all demodulation–based digital
TV measurements.
Close the Digital TV Settings dialog with the ESC key.
What is the difference between the equalizer filter and the echo pattern?
The echo pattern is the amplitude of the channel impulse response. The equalizer in contrast estimates
the inverse of the channel response which is required to remove the channel's influence from the
measurement signal.
Channel Power measurement
This measurement determines the channel power of a digital TV channel.
For details on the applied measurement modes refer to section Measuring Channel Power and
Adjacent Channel Power.
The measurement is setup automatically with data relating to the modulation standard.
The measurement display is split into two panes. In the upper pane, the spectrum trace is displayed. In
the lower pane, the result table for the measurement is displayed.
Test setup:
Refer to the section Digital TV test setup.
Procedure:
1. Press the MEAS key.
2. Press the Digital TV softkey.
3. Press the More softkey.
4. Press the Channel Power softkey.
5. To change the limits, press the Edit Table softkey.
6. To adjust the input attenuator, press the Adjust Attenuation softkey.
7. Press the RUN key.
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