PT 5780 DVB-T Modulator
ProTelevision Technologies
Operating Instructions
Instruction Manual
Revision 3.11
4-17
ID 2340). The menu for setting the peak clipping level allows the user to control the ratio
between peak power and average RMS power of the COFDM spectrum. If the clip level is set to
0dB the peak power is limited to +17dB relative to average RMS power. If the clip level is
increased to 4dB the peak power relative to average RMS power will be limited to 13dB. The
average RMS power remains unchanged.
Peak level = 17dB – clip level – precorrector gain
The clip function is implemented as hard clipping without band limitation. The definition of pre-
correction curves must be done via the remote interface by means of the separate PC software
tool (IMD Buster) supplied with the pre-corrector option.
Linear Pre -Correction (ID 2400)
This menu allows the user to control the linear pre-corrector function (only available when
option PT 8731 is installed). Sub menus are available for switching the linear pre-corrector
function on/off (menu ID 2410) and for recalling a correction curve from the preset library (menu
ID 2420). The definition of pre-correction curves must be done via the remote interface by
means of the separate PC software tool (IMD Buster) supplied with the pre-corrector option.
Monitor (ID 2500)
This menu allows the user to specify which signal that is to be routed to the monitor output
located in the rear panel of the DVB-T modulator. It is possible to monitor the following signals:
Menu choice
Description
Remarks
HP Input
Monitors the selected input
(HP input by hierarchical
mode) before any processing
has taken place
HP Output
Monitors the selected input
(HP input by hierarchical
mode) after the transport
stream bit rate adaptation has
taken place.
LP Input
Monitors the selected LP input
before any processing has
taken place
Only available in hierarchical
mode
LP Output
Monitors the selected LP input
after the transport stream bit
rate adaptation has taken
place.
Only available in hierarchical
mode
Demodulator
Monitors the output from the
on-board COFDM
demodulator (i.e. the transport
stream obtained by
demodulating the modulators
IF output)
Summary of Contents for PT 5780
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