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.
90