1.. Permission is granted to copy, distribute and/or modify this
2.. document under the terms of the GNU Free Documentation License,
3.. Version 1.1 or any later version published by the Free Software
4.. Foundation, with no Invariant Sections, no Front-Cover Texts
5.. and no Back-Cover Texts. A copy of the license is included at
6.. Documentation/userspace-api/media/fdl-appendix.rst.
7..
8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
9
10.. _rf-tuner-controls:
11
12**************************
13RF Tuner Control Reference
14**************************
15
16The RF Tuner (RF_TUNER) class includes controls for common features of
17devices having RF tuner.
18
19In this context, RF tuner is radio receiver circuit between antenna and
20demodulator. It receives radio frequency (RF) from the antenna and
21converts that received signal to lower intermediate frequency (IF) or
22baseband frequency (BB). Tuners that could do baseband output are often
23called Zero-IF tuners. Older tuners were typically simple PLL tuners
24inside a metal box, while newer ones are highly integrated chips
25without a metal box "silicon tuners". These controls are mostly
26applicable for new feature rich silicon tuners, just because older
27tuners does not have much adjustable features.
28
29For more information about RF tuners see
30`Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__
31and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__
32from Wikipedia.
33
34
35.. _rf-tuner-control-id:
36
37RF_TUNER Control IDs
38====================
39
40``V4L2_CID_RF_TUNER_CLASS (class)``
41    The RF_TUNER class descriptor. Calling
42    :ref:`VIDIOC_QUERYCTRL` for this control will
43    return a description of this control class.
44
45``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)``
46    Enables/disables tuner radio channel bandwidth configuration. In
47    automatic mode bandwidth configuration is performed by the driver.
48
49``V4L2_CID_RF_TUNER_BANDWIDTH (integer)``
50    Filter(s) on tuner signal path are used to filter signal according
51    to receiving party needs. Driver configures filters to fulfill
52    desired bandwidth requirement. Used when
53    V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The
54    range and step are driver-specific.
55
56``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)``
57    Enables/disables LNA automatic gain control (AGC)
58
59``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)``
60    Enables/disables mixer automatic gain control (AGC)
61
62``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)``
63    Enables/disables IF automatic gain control (AGC)
64
65``V4L2_CID_RF_TUNER_RF_GAIN (integer)``
66    The RF amplifier is the very first amplifier on the receiver signal
67    path, just right after the antenna input. The difference between the
68    LNA gain and the RF gain in this document is that the LNA gain is
69    integrated in the tuner chip while the RF gain is a separate chip.
70    There may be both RF and LNA gain controls in the same device. The
71    range and step are driver-specific.
72
73``V4L2_CID_RF_TUNER_LNA_GAIN (integer)``
74    LNA (low noise amplifier) gain is first gain stage on the RF tuner
75    signal path. It is located very close to tuner antenna input. Used
76    when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See
77    ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain
78    differs from the each others. The range and step are
79    driver-specific.
80
81``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)``
82    Mixer gain is second gain stage on the RF tuner signal path. It is
83    located inside mixer block, where RF signal is down-converted by the
84    mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set.
85    The range and step are driver-specific.
86
87``V4L2_CID_RF_TUNER_IF_GAIN (integer)``
88    IF gain is last gain stage on the RF tuner signal path. It is
89    located on output of RF tuner. It controls signal level of
90    intermediate frequency output or baseband output. Used when
91    ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step
92    are driver-specific.
93
94``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)``
95    Is synthesizer PLL locked? RF tuner is receiving given frequency
96    when that control is set. This is a read-only control.
97