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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2 3.. _rf-tuner-controls:4 5**************************6RF Tuner Control Reference7**************************8 9The RF Tuner (RF_TUNER) class includes controls for common features of10devices having RF tuner.11 12In this context, RF tuner is radio receiver circuit between antenna and13demodulator. It receives radio frequency (RF) from the antenna and14converts that received signal to lower intermediate frequency (IF) or15baseband frequency (BB). Tuners that could do baseband output are often16called Zero-IF tuners. Older tuners were typically simple PLL tuners17inside a metal box, while newer ones are highly integrated chips18without a metal box "silicon tuners". These controls are mostly19applicable for new feature rich silicon tuners, just because older20tuners does not have much adjustable features.21 22For more information about RF tuners see23`Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__24and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__25from Wikipedia.26 27 28.. _rf-tuner-control-id:29 30RF_TUNER Control IDs31====================32 33``V4L2_CID_RF_TUNER_CLASS (class)``34 The RF_TUNER class descriptor. Calling35 :ref:`VIDIOC_QUERYCTRL` for this control will36 return a description of this control class.37 38``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)``39 Enables/disables tuner radio channel bandwidth configuration. In40 automatic mode bandwidth configuration is performed by the driver.41 42``V4L2_CID_RF_TUNER_BANDWIDTH (integer)``43 Filter(s) on tuner signal path are used to filter signal according44 to receiving party needs. Driver configures filters to fulfill45 desired bandwidth requirement. Used when46 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The47 range and step are driver-specific.48 49``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)``50 Enables/disables LNA automatic gain control (AGC)51 52``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)``53 Enables/disables mixer automatic gain control (AGC)54 55``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)``56 Enables/disables IF automatic gain control (AGC)57 58``V4L2_CID_RF_TUNER_RF_GAIN (integer)``59 The RF amplifier is the very first amplifier on the receiver signal60 path, just right after the antenna input. The difference between the61 LNA gain and the RF gain in this document is that the LNA gain is62 integrated in the tuner chip while the RF gain is a separate chip.63 There may be both RF and LNA gain controls in the same device. The64 range and step are driver-specific.65 66``V4L2_CID_RF_TUNER_LNA_GAIN (integer)``67 LNA (low noise amplifier) gain is first gain stage on the RF tuner68 signal path. It is located very close to tuner antenna input. Used69 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See70 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain71 differs from the each others. The range and step are72 driver-specific.73 74``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)``75 Mixer gain is second gain stage on the RF tuner signal path. It is76 located inside mixer block, where RF signal is down-converted by the77 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set.78 The range and step are driver-specific.79 80``V4L2_CID_RF_TUNER_IF_GAIN (integer)``81 IF gain is last gain stage on the RF tuner signal path. It is82 located on output of RF tuner. It controls signal level of83 intermediate frequency output or baseband output. Used when84 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step85 are driver-specific.86 87``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)``88 Is synthesizer PLL locked? RF tuner is receiving given frequency89 when that control is set. This is a read-only control.90