.. _transmitting:

============
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:

.. code-block:: none

    [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 :ref:`ipfwd` and :ref:`ethdata`
for more information on how to supply payload data to the transmitter.

.. _idlebb:

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 :ref:`idle_properties`, :ref:`ethdata`
and [ETSI_EN]_ section 5 for more details.
