RS232 Communication
ProTelevision Technologies
PT 5780 DVB-T Modulator
Instruction Manual
Revision 3.11
6-12
•
OUTPut:BANDwidth
Command to select the output channel bandwidth. Parameters available for this command are
6, 7 and 8 MHz. However the 6 MHz parameter option is only available if the 6 MHz option is
installed and enabled in the modulator.
Example:
OUTP:BAND 7
Select a 7 MHz bandwidth.
OUTP:BAND?
Response:
7
•
OUTPut:WINDow:ENABle
Command for enabling (ON) and disabling (OFF) the spectrum window filter.
Example:
OUTP:WIND:ENAB ON
Activate spectrum window filter.
OUTP:WIND:ENAB?
Response:
ON
•
OUTPut:WINDow:ROLLoff
Command for setting the spectrum window filter roll-off. The parameter choices are
1
/
64
,
1
/
128
,
1
/
256
and
1
/
512
.
Note: The parameter
1
/
X
specifies the proportion out of the total number of symbol samples
(useful guard interval) that are used for creating the smooth transition between
consecutive symbols. The largest proportion (
1
/
64
) gives the highest sideband suppression and
the lowest proportion (
1
/
512
) gives the lowest suppression. There is a trade off between useful
guard interval and sideband suppression.
Example:
OUTP:WIND:ROLL W1_64
Set window filter roll off to 1/64.
OUTP:WIND:ROLL?
Response:
W1_64
•
OUTPut:WINDow?
Query command to list the spectrum window filter and the spectrum window filter roll off
settings.
Example:
OUTP:WIND?
Response:
ON, W1_64
•
OUTPut:POLarity
Command to set the spectrum polarity to either normal or inverted.
Example
OUTP:POL INV
Invert spectrum.
OUTP:POL?
Response
: INV
•
OUTPut:PEAK:CLIPping
Command to set the signal peak clipping (-10 to 0 dB) . The peak clipping affects the back-off
(headroom) as follows: Back-off = 17dB – Peak-clipping – Gain. For example, by 5dB peak
clipping and 0 dB gain setting the back-off will be 12dB. That is, the distance between the
output RMS level and the output clip level is 12dB.
Summary of Contents for PT 5780
Page 94: ......
