DVB-H User Interface
DVB-H
32
Operating Manual 1008.0970.12 ─ 16
Cut Off Frequency Shift
(available for filter parameter Cosine only)
Sets the value for the cut off frequency shift. The cut off frequency of the cosine filter
can be adjusted to reach spectrum mask requirements.
Remote command:
[:SOURce<hw>]:BB:DVB:FILTer:PARameter:COSine:COFS
Cut Off Frequency Factor
Sets the value for the cut off frequency factor. The cut off frequency of the filter can be
adjusted to reach spectrum mask requirements.
Remote command:
[:SOURce<hw>]:BB:DVB:FILTer:PARameter:LPASs
[:SOURce<hw>]:BB:DVB:FILTer:PARameter:LPASSEVM
Sample Rate Variation
Sets the sample rate of the signal. A variation of this parameter only affects the ARB
clock rate; all other signal parameters remain unchanged.
Remote command:
[:SOURce<hw>]:BB:DVB:SRATe:VARiation
3.4.2 Clipping Settings
DVB-H signals may have a quite high crest factor (~ 11dBm) because of high ampli-
tude variations that come along with OFDM signals having a noise-like spectrum. High
crest factors entail two basic problems:
●
The nonlinearity of the power amplifier (compression) causes intermodulation
which expands the spectrum (spectral regrowth).
●
Since the level in the D/A converter is relative to the maximum value, the average
value is converted with a relatively low resolution. This results in a high quantiza-
tion noise.
Both effects increase the adjacent-channel power.
Since clipping the signal not only changes the peak value but also the average value,
the effect on the crest factor is unpredictable.
The following pictures demonstrate the affect of clipping with vector mode (|i+jq|), using
the default signal configuration with a PN23 input sequence.
Filter / Clipping Settings
Summary of Contents for 1402.9557.02
Page 8: ...Preface DVB H 8 Operating Manual 1008 0970 12 16 Conventions Used in the Documentation ...
Page 44: ...DVB H User Interface DVB H 44 Operating Manual 1008 0970 12 16 Trigger Marker Clock Settings ...
Page 76: ...Remote control commands DVB H 76 Operating Manual 1008 0970 12 16 TPS Settings ...