0001 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
0002
0003 .. _rf-tuner-controls:
0004
0005 **************************
0006 RF Tuner Control Reference
0007 **************************
0008
0009 The RF Tuner (RF_TUNER) class includes controls for common features of
0010 devices having RF tuner.
0011
0012 In this context, RF tuner is radio receiver circuit between antenna and
0013 demodulator. It receives radio frequency (RF) from the antenna and
0014 converts that received signal to lower intermediate frequency (IF) or
0015 baseband frequency (BB). Tuners that could do baseband output are often
0016 called Zero-IF tuners. Older tuners were typically simple PLL tuners
0017 inside a metal box, while newer ones are highly integrated chips
0018 without a metal box "silicon tuners". These controls are mostly
0019 applicable for new feature rich silicon tuners, just because older
0020 tuners does not have much adjustable features.
0021
0022 For more information about RF tuners see
0023 `Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__
0024 and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__
0025 from Wikipedia.
0026
0027
0028 .. _rf-tuner-control-id:
0029
0030 RF_TUNER Control IDs
0031 ====================
0032
0033 ``V4L2_CID_RF_TUNER_CLASS (class)``
0034 The RF_TUNER class descriptor. Calling
0035 :ref:`VIDIOC_QUERYCTRL` for this control will
0036 return a description of this control class.
0037
0038 ``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)``
0039 Enables/disables tuner radio channel bandwidth configuration. In
0040 automatic mode bandwidth configuration is performed by the driver.
0041
0042 ``V4L2_CID_RF_TUNER_BANDWIDTH (integer)``
0043 Filter(s) on tuner signal path are used to filter signal according
0044 to receiving party needs. Driver configures filters to fulfill
0045 desired bandwidth requirement. Used when
0046 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The
0047 range and step are driver-specific.
0048
0049 ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)``
0050 Enables/disables LNA automatic gain control (AGC)
0051
0052 ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)``
0053 Enables/disables mixer automatic gain control (AGC)
0054
0055 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)``
0056 Enables/disables IF automatic gain control (AGC)
0057
0058 ``V4L2_CID_RF_TUNER_RF_GAIN (integer)``
0059 The RF amplifier is the very first amplifier on the receiver signal
0060 path, just right after the antenna input. The difference between the
0061 LNA gain and the RF gain in this document is that the LNA gain is
0062 integrated in the tuner chip while the RF gain is a separate chip.
0063 There may be both RF and LNA gain controls in the same device. The
0064 range and step are driver-specific.
0065
0066 ``V4L2_CID_RF_TUNER_LNA_GAIN (integer)``
0067 LNA (low noise amplifier) gain is first gain stage on the RF tuner
0068 signal path. It is located very close to tuner antenna input. Used
0069 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See
0070 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain
0071 differs from the each others. The range and step are
0072 driver-specific.
0073
0074 ``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)``
0075 Mixer gain is second gain stage on the RF tuner signal path. It is
0076 located inside mixer block, where RF signal is down-converted by the
0077 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set.
0078 The range and step are driver-specific.
0079
0080 ``V4L2_CID_RF_TUNER_IF_GAIN (integer)``
0081 IF gain is last gain stage on the RF tuner signal path. It is
0082 located on output of RF tuner. It controls signal level of
0083 intermediate frequency output or baseband output. Used when
0084 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step
0085 are driver-specific.
0086
0087 ``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)``
0088 Is synthesizer PLL locked? RF tuner is receiving given frequency
0089 when that control is set. This is a read-only control.
