Digital Modulation SME
1038.6002.02 2.122 E-13
FORWARD CHANNEL
Together with FREQUENCY SPACING the next two settings
determine the frequency of the channel from the transmitter
(SME) to the receiver. The following formula is valid in this case:
FREQ = FORW CHAN BASE FREQUENCY +
FORW CHAN ASSIGNMENT NUMBER * FREQUENCY SPACING
If AUTO ADAPTATION is switched to ON, the frequency
calculated when switching on ReFLEX25 and executing
RECALCULATE is also transferred to the RF setting of the SME,
provided the formula provides a value that lies within the setting
range of the SME.
The preset values for the following parameters are selected such
that the default value of 929.00625 MHz specified in the
ReFLEX25 documentation is obtained as frequency.
BASE FREQUENCY
Base frequency of forward channel. Valid values are 0 to 8191
MHz. This exceeds the setting range of the SME. Nevertheless,
the set value is transferred to the receiver without being changed.
IEC-bus command: SOUR:REFL25:SI:FCH:BASE 929MHz
ASSIGNMENT NUMBER
Frequency assignment number. This is
not
the logic channel
number. Valid values are 0 to 2047.
IEC-bus command: SOUR:REFL25:SI:FCH:ANUM 1
REVERSE CHANNEL
Together with FREQUENCY SPACING, the next two settings
determine the frequency of the reverse channel from the receiver
to the transmitter (SME). The following formula is valid in this
case:
FREQ = REV CHAN BASE FREQUENCY +
REV CHAN ASSIGNMENT NUMBER * FREQUENCY SPACING
In addition, the bit rate of the reverse channel is specified.
The preset values for the following parameters are selected such
that the default value of 896.0125 MHz specified in the ReFLEX25
documentation is obtained as frequency.
BASE FREQUENCY
Base frequency of the reverse channel. Valid values are 0 to 8191
MHz.
IEC-bus command: SOUR:REFL25:SI:RCH:BASE 896MHz
ASSIGNMENT NUMBER
Frequency assignment number. This is
not
the logic channel
number. Valid values are 0 to 2047.
IEC-bus command: SOUR:REFL25:SI:RCH:ANUM 2
SPEED
Selection of bit rate of reverse channel. Possible selections are
800bps, 1600bps, 6400bps and 9600bps.
IEC-bus command: SOUR:REFL25:SI:RCH:SPE 800bps
FREQUENCY SPACING
Determines the frequency spacing according to the above
formulas for FREQ. This setting applies both to forward and
reverse channel. Valid values are 0 to 102350Hz, in steps of
50Hz.
IEC-bus command: SOUR:REFL25:SI:FSP 6250Hz
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