Tektronix MTM400 - Manual (Page 154)

Interface Configuration and Interpretation
3-110 MTM400 MPEG Transport Stream Monitor User Manual
Configurations Allows you to select from a range of preset L-Band
configurations.
The configurations are made available by the MTM400
configuration file (see MTM400 Configuration Files,
page 3
-85.).
You can activate an L-Band configuration by highlighting the
name in the Configurations field; the field below will display
the message ‘Updating values’ until the settings are recalled.
Local Oscillator Frequency (GHz)
The Local Oscillator (LO) frequency of the Low Noise Block
(LNB) is dependent on the Transponder frequency and must be
such that the difference falls within the input range of the
receiver. Typically, these values are 10.6 GHz (Hi-Band) and
9.75 GHz (Lo-Band) when converting from KU band. The
values are 5.7 GHz (Hi-Band) and 5.15 GHz (Lo-Band
respectively when converting from C-Band. This information
should be confirmed for the specific type of LNBs used.
Enter the required value and select Set.
Transponder Frequency (GHz)
The IF frequency that is used to initialize the L-Band Interface
card is calculated as follows:
Transponder_Frequency – LO_Frequency.
If you want to specify the IF frequency rather than the individual
LO and Transponder frequencies, set the Local Oscillator
Frequency to a value of 0 (zero) and specify the required IF
frequency under this parameter. If the IF frequency is specified,
it must be in the range 0.950 GHz to 2.150 GHz; the tuning
increment is 125 kHz.
Enter the required value and select Set.
Polarisation (Volts)
This parameter selects the polarization by applying 13 V
(vertical) or 18 V (horizontal) to the LNB (Low Noise Block).
A value of 0 can be used if no voltage is to be applied from this
card; for example, if the polarization voltage is being supplied
from an external source.
Viterbi Rate Select the code rate from the drop-down list: 1/2; 2/3; 3/4; 5/6;
6/7; 7/8. Note that it may be overwritten if the Viterbi Rate
Auto selection is enabled.