ext-ctrls-rf-tuner.rst (3758B)
1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _rf-tuner-controls: 4 5************************** 6RF Tuner Control Reference 7************************** 8 9The RF Tuner (RF_TUNER) class includes controls for common features of 10devices having RF tuner. 11 12In this context, RF tuner is radio receiver circuit between antenna and 13demodulator. It receives radio frequency (RF) from the antenna and 14converts that received signal to lower intermediate frequency (IF) or 15baseband frequency (BB). Tuners that could do baseband output are often 16called Zero-IF tuners. Older tuners were typically simple PLL tuners 17inside a metal box, while newer ones are highly integrated chips 18without a metal box "silicon tuners". These controls are mostly 19applicable for new feature rich silicon tuners, just because older 20tuners does not have much adjustable features. 21 22For more information about RF tuners see 23`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 IDs 31==================== 32 33``V4L2_CID_RF_TUNER_CLASS (class)`` 34 The RF_TUNER class descriptor. Calling 35 :ref:`VIDIOC_QUERYCTRL` for this control will 36 return a description of this control class. 37 38``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)`` 39 Enables/disables tuner radio channel bandwidth configuration. In 40 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 according 44 to receiving party needs. Driver configures filters to fulfill 45 desired bandwidth requirement. Used when 46 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The 47 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 signal 60 path, just right after the antenna input. The difference between the 61 LNA gain and the RF gain in this document is that the LNA gain is 62 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. The 64 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 tuner 68 signal path. It is located very close to tuner antenna input. Used 69 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See 70 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain 71 differs from the each others. The range and step are 72 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 is 76 located inside mixer block, where RF signal is down-converted by the 77 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 is 82 located on output of RF tuner. It controls signal level of 83 intermediate frequency output or baseband output. Used when 84 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step 85 are driver-specific. 86 87``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)`` 88 Is synthesizer PLL locked? RF tuner is receiving given frequency 89 when that control is set. This is a read-only control.