1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _rf-tuner-controls: 5 6************************** 7RF Tuner Control Reference 8************************** 9 10The RF Tuner (RF_TUNER) class includes controls for common features of 11devices having RF tuner. 12 13In this context, RF tuner is radio receiver circuit between antenna and 14demodulator. It receives radio frequency (RF) from the antenna and 15converts that received signal to lower intermediate frequency (IF) or 16baseband frequency (BB). Tuners that could do baseband output are often 17called Zero-IF tuners. Older tuners were typically simple PLL tuners 18inside a metal box, while newer ones are highly integrated chips 19without a metal box "silicon tuners". These controls are mostly 20applicable for new feature rich silicon tuners, just because older 21tuners does not have much adjustable features. 22 23For more information about RF tuners see 24`Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__ 25and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__ 26from Wikipedia. 27 28 29.. _rf-tuner-control-id: 30 31RF_TUNER Control IDs 32==================== 33 34``V4L2_CID_RF_TUNER_CLASS (class)`` 35 The RF_TUNER class descriptor. Calling 36 :ref:`VIDIOC_QUERYCTRL` for this control will 37 return a description of this control class. 38 39``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)`` 40 Enables/disables tuner radio channel bandwidth configuration. In 41 automatic mode bandwidth configuration is performed by the driver. 42 43``V4L2_CID_RF_TUNER_BANDWIDTH (integer)`` 44 Filter(s) on tuner signal path are used to filter signal according 45 to receiving party needs. Driver configures filters to fulfill 46 desired bandwidth requirement. Used when 47 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The 48 range and step are driver-specific. 49 50``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)`` 51 Enables/disables LNA automatic gain control (AGC) 52 53``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)`` 54 Enables/disables mixer automatic gain control (AGC) 55 56``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)`` 57 Enables/disables IF automatic gain control (AGC) 58 59``V4L2_CID_RF_TUNER_RF_GAIN (integer)`` 60 The RF amplifier is the very first amplifier on the receiver signal 61 path, just right after the antenna input. The difference between the 62 LNA gain and the RF gain in this document is that the LNA gain is 63 integrated in the tuner chip while the RF gain is a separate chip. 64 There may be both RF and LNA gain controls in the same device. The 65 range and step are driver-specific. 66 67``V4L2_CID_RF_TUNER_LNA_GAIN (integer)`` 68 LNA (low noise amplifier) gain is first gain stage on the RF tuner 69 signal path. It is located very close to tuner antenna input. Used 70 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See 71 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain 72 differs from the each others. The range and step are 73 driver-specific. 74 75``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)`` 76 Mixer gain is second gain stage on the RF tuner signal path. It is 77 located inside mixer block, where RF signal is down-converted by the 78 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set. 79 The range and step are driver-specific. 80 81``V4L2_CID_RF_TUNER_IF_GAIN (integer)`` 82 IF gain is last gain stage on the RF tuner signal path. It is 83 located on output of RF tuner. It controls signal level of 84 intermediate frequency output or baseband output. Used when 85 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step 86 are driver-specific. 87 88``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)`` 89 Is synthesizer PLL locked? RF tuner is receiving given frequency 90 when that control is set. This is a read-only control. 91