Transmitting

This section describes how to configure and key up the SRX-8 transmitter.

To key up the transmitter, set tx.enable to true and wait approximately 1 second for the transmitter to complete the key up sequence.

By default, the SRX-8 transmitter will emit dummy PLFRAMEs if no user data is supplied to the transmitter. Dummy PLFRAMEs are described in [ETSI_EN] section 5.5.1.

Modifying tx.freq, tx.rate or tx.pout will automatically trigger a key down followed by a key up if the transmitter is already transmitting. It is recommended to configure these prior to setting tx.enable to true.

An example of how to configure and key up the transmitter is shown below:

[srx-8] prop set tx.pout 30
[srx-8] prop set tx.rate 150000000
[srx-8] prop list tx
Property        Type  Stat  Flag  Value
enable          bool  D     NR    false
freq            u64   D     -     8200000000 hz
rate            u32   D     -     150000000 baud
rolloff         u8    D     -     0
goldseq         u32   D     -     0
pout            flt   D     -     30.00 dBm
pa.templimit    u8    D     -     80
bbframes        u64   M     NR    0 frames
pwr.fwd         flt   M     NR    0.00 dBm
pwr.rfl         flt   M     NR    0.00 dBm
volt.vga.vc     u16   M     NR    0 mV
volt.drv.vg     i16   M     NR    -2049 mV
volt.pa.vg      i16   M     NR    -3999 mV
gain            flt   M     NR    0.00 %
[srx-8] prop set tx.enable true
<Wait a second>
[srx-8] prop list tx
Property        Type  Stat  Flag  Value
enable          bool  M     NR    true
freq            u64   D     -     8200000000 hz
rate            u32   D     -     150000000 baud
rolloff         u8    D     -     0
goldseq         u32   D     -     0
pout            flt   M     -     30.00 dBm
pa.templimit    u8    D     -     80
bbframes        u64   M     NR    0 frames
pwr.fwd         flt   M     NR    29.94 dBm
pwr.rfl         flt   M     NR    23.63 dBm
volt.vga.vc     u16   M     NR    2035 mV
volt.drv.vg     i16   M     NR    -1149 mV
volt.pa.vg      i16   M     NR    -3082 mV
gain            flt   M     NR    29.56 %

The transmitter is now transmitting dummy PLFRAMEs. See IP Forwarding and BBFRAME Data Service for more information on how to supply payload data to the transmitter.

Idle BBFRAMEs

Some DVB-S2 receiver equipment requires BBFRAMEs with idle data instead of dummy PLFRAMEs in order to lock.

To transmit idle BBFRAMEs, set the enable property in the idle property group to true. This will generate a generic continuous stream (TS/GS = 01) of zero-length (DFL = 0) BBFRAMEs, which will fill the link whenever it is not fully utilized. The properties in the ìdle table can be used to modify the idle BBFRAME format. Refer to Idle BBFRAME Generator Group, BBFRAME Data Service and [ETSI_EN] section 5 for more details.