Functional description of the headend station
After connecting the headend station to the mains voltage, all cassettes (max. 8)
are supplied with the required operating voltages by a switched-mode power
supply unit via the plug-in connectors on the contact rail.
The passive input splitter provides highest flexibility when selecting signals with
horizontal or vertical polarization.
The SAT cassettes are connected to the INPUT A and INPUT B of the input splitter.
The INPUT A and INPUT B can be operated from a remote voltage supply, that
is, the LNC can be supplied with an operating voltage of +18 V/max.1 A ј.
All output signals of the cassettes are added up in the output collector then passed
on to the hybrid amplifier.
The hybrid amplifier delivers an output level of max. 106 dBµV.
The necessary operating voltage of +24 V јis supplied by the switched-mode
power supply unit.
The output levels of the individual cassettes must be exactly adjusted to each other
by means of the 8 level controls located on the front panel of the headend station.
An additional monitor output (approximately -20 dB) enables the connection of a
measuring TV receiver for service or monitoring purposes.
Predetermined break-outs B(see Fig.) for additional aerial inputs and the con-
nection of external devices (e.g a descrambler via a EURO-AV cable) facilitate
retrofitting.
Using the keys on the control unit you may select, change and save all input and
output parameters of the individual cassettes.
The user is guided by the 2-line display.
The software version of the headend station’s control unit can be indicated on the
diplay in the following way:
Press two keys, e.g., »+« and »–« on the control unit at the same time and hold
them down until the following occurs:
– The display turns dark and after about 5 seconds appears the software iden-
tification with the last two digits indicating the software version.
The sockets »SERVICE« (only for production purposes) and »RS 232« are serial
interfaces provided for PC-aided programming and downloading of updated soft-
ware for the control unit of the headend station.
It is also possible to operate the headend station with less than 8 twin or single
cassettes, and to link several headend stations with each other.
