1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 2
3 .. _rf-tuner-controls: 3 .. _rf-tuner-controls:
4 4
5 ************************** 5 **************************
6 RF Tuner Control Reference 6 RF Tuner Control Reference
7 ************************** 7 **************************
8 8
9 The RF Tuner (RF_TUNER) class includes control 9 The RF Tuner (RF_TUNER) class includes controls for common features of
10 devices having RF tuner. 10 devices having RF tuner.
11 11
12 In this context, RF tuner is radio receiver ci 12 In this context, RF tuner is radio receiver circuit between antenna and
13 demodulator. It receives radio frequency (RF) 13 demodulator. It receives radio frequency (RF) from the antenna and
14 converts that received signal to lower interme 14 converts that received signal to lower intermediate frequency (IF) or
15 baseband frequency (BB). Tuners that could do 15 baseband frequency (BB). Tuners that could do baseband output are often
16 called Zero-IF tuners. Older tuners were typic 16 called Zero-IF tuners. Older tuners were typically simple PLL tuners
17 inside a metal box, while newer ones are highl 17 inside a metal box, while newer ones are highly integrated chips
18 without a metal box "silicon tuners". These co 18 without a metal box "silicon tuners". These controls are mostly
19 applicable for new feature rich silicon tuners 19 applicable for new feature rich silicon tuners, just because older
20 tuners does not have much adjustable features. 20 tuners does not have much adjustable features.
21 21
22 For more information about RF tuners see 22 For more information about RF tuners see
23 `Tuner (radio) <http://en.wikipedia.org/wiki/T 23 `Tuner (radio) <http://en.wikipedia.org/wiki/Tuner_%28radio%29>`__
24 and `RF front end <http://en.wikipedia.org/wik 24 and `RF front end <http://en.wikipedia.org/wiki/RF_front_end>`__
25 from Wikipedia. 25 from Wikipedia.
26 26
27 27
28 .. _rf-tuner-control-id: 28 .. _rf-tuner-control-id:
29 29
30 RF_TUNER Control IDs 30 RF_TUNER Control IDs
31 ==================== 31 ====================
32 32
33 ``V4L2_CID_RF_TUNER_CLASS (class)`` 33 ``V4L2_CID_RF_TUNER_CLASS (class)``
34 The RF_TUNER class descriptor. Calling 34 The RF_TUNER class descriptor. Calling
35 :ref:`VIDIOC_QUERYCTRL` for this control w 35 :ref:`VIDIOC_QUERYCTRL` for this control will
36 return a description of this control class 36 return a description of this control class.
37 37
38 ``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)`` 38 ``V4L2_CID_RF_TUNER_BANDWIDTH_AUTO (boolean)``
39 Enables/disables tuner radio channel bandw 39 Enables/disables tuner radio channel bandwidth configuration. In
40 automatic mode bandwidth configuration is 40 automatic mode bandwidth configuration is performed by the driver.
41 41
42 ``V4L2_CID_RF_TUNER_BANDWIDTH (integer)`` 42 ``V4L2_CID_RF_TUNER_BANDWIDTH (integer)``
43 Filter(s) on tuner signal path are used to 43 Filter(s) on tuner signal path are used to filter signal according
44 to receiving party needs. Driver configure 44 to receiving party needs. Driver configures filters to fulfill
45 desired bandwidth requirement. Used when 45 desired bandwidth requirement. Used when
46 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not se 46 V4L2_CID_RF_TUNER_BANDWIDTH_AUTO is not set. Unit is in Hz. The
47 range and step are driver-specific. 47 range and step are driver-specific.
48 48
49 ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)`` 49 ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO (boolean)``
50 Enables/disables LNA automatic gain contro 50 Enables/disables LNA automatic gain control (AGC)
51 51
52 ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)` 52 ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO (boolean)``
53 Enables/disables mixer automatic gain cont 53 Enables/disables mixer automatic gain control (AGC)
54 54
55 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)`` 55 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO (boolean)``
56 Enables/disables IF automatic gain control 56 Enables/disables IF automatic gain control (AGC)
57 57
58 ``V4L2_CID_RF_TUNER_RF_GAIN (integer)`` 58 ``V4L2_CID_RF_TUNER_RF_GAIN (integer)``
59 The RF amplifier is the very first amplifi 59 The RF amplifier is the very first amplifier on the receiver signal
60 path, just right after the antenna input. 60 path, just right after the antenna input. The difference between the
61 LNA gain and the RF gain in this document 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 62 integrated in the tuner chip while the RF gain is a separate chip.
63 There may be both RF and LNA gain controls 63 There may be both RF and LNA gain controls in the same device. The
64 range and step are driver-specific. 64 range and step are driver-specific.
65 65
66 ``V4L2_CID_RF_TUNER_LNA_GAIN (integer)`` 66 ``V4L2_CID_RF_TUNER_LNA_GAIN (integer)``
67 LNA (low noise amplifier) gain is first ga 67 LNA (low noise amplifier) gain is first gain stage on the RF tuner
68 signal path. It is located very close to t 68 signal path. It is located very close to tuner antenna input. Used
69 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` i 69 when ``V4L2_CID_RF_TUNER_LNA_GAIN_AUTO`` is not set. See
70 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understan 70 ``V4L2_CID_RF_TUNER_RF_GAIN`` to understand how RF gain and LNA gain
71 differs from the each others. The range an 71 differs from the each others. The range and step are
72 driver-specific. 72 driver-specific.
73 73
74 ``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)`` 74 ``V4L2_CID_RF_TUNER_MIXER_GAIN (integer)``
75 Mixer gain is second gain stage on the RF 75 Mixer gain is second gain stage on the RF tuner signal path. It is
76 located inside mixer block, where RF signa 76 located inside mixer block, where RF signal is down-converted by the
77 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER 77 mixer. Used when ``V4L2_CID_RF_TUNER_MIXER_GAIN_AUTO`` is not set.
78 The range and step are driver-specific. 78 The range and step are driver-specific.
79 79
80 ``V4L2_CID_RF_TUNER_IF_GAIN (integer)`` 80 ``V4L2_CID_RF_TUNER_IF_GAIN (integer)``
81 IF gain is last gain stage on the RF tuner 81 IF gain is last gain stage on the RF tuner signal path. It is
82 located on output of RF tuner. It controls 82 located on output of RF tuner. It controls signal level of
83 intermediate frequency output or baseband 83 intermediate frequency output or baseband output. Used when
84 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not 84 ``V4L2_CID_RF_TUNER_IF_GAIN_AUTO`` is not set. The range and step
85 are driver-specific. 85 are driver-specific.
86 86
87 ``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)`` 87 ``V4L2_CID_RF_TUNER_PLL_LOCK (boolean)``
88 Is synthesizer PLL locked? RF tuner is rec 88 Is synthesizer PLL locked? RF tuner is receiving given frequency
89 when that control is set. This is a read-o 89 when that control is set. This is a read-only control.
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