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Linux 6.18.37 · Userspace API / Media / V4L

FM Receiver Control Reference

FM 수신기의 RDS 정보와 지역별 de-emphasis 제어를 설명합니다.

Source pathDocumentation/userspace-api/media/v4l/ext-ctrls-fm-rx.rst
Source versionLinux v6.18.37
TranslationDUJINLABS 전문 번역 + 해설

요약·해설과 원문, 전문 번역을 서로 분리했습니다. API 이름, symbol, source path는 원문 표기를 사용합니다.

1. 요약·해설

원문의 핵심 논리와 kernel programming 관점의 보충 설명입니다. 아래의 전문 번역과는 별도로 작성했습니다.

요약·해설

ext-ctrls-fm-rx.rst:1-83

FM 수신기 API는 RDS의 서비스 이름과 방송 설명을 규격 단위로 읽고, 송신 지역에 맞는 50 us 또는 75 us de-emphasis를 적용합니다.

2. 영어 원문 전체

번역 기준이 된 Linux v6.18.37 원문입니다. 줄 번호는 이 버전의 파일 좌표입니다.

원문 전체 펼치기
1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3 .. _fm-rx-controls:
4
5 *****************************
6 FM Receiver Control Reference
7 *****************************
8
9 The FM Receiver (FM_RX) class includes controls for common features of
10 FM Reception capable devices.
11
12
13 .. _fm-rx-control-id:
14
15 FM_RX Control IDs
16 =================
17
18 ``V4L2_CID_FM_RX_CLASS (class)``
19 The FM_RX class descriptor. Calling
20 :ref:`VIDIOC_QUERYCTRL` for this control will
21 return a description of this control class.
22
23 ``V4L2_CID_RDS_RECEPTION (boolean)``
24 Enables/disables RDS reception by the radio tuner
25
26 ``V4L2_CID_RDS_RX_PTY (integer)``
27 Gets RDS Programme Type field. This encodes up to 31 pre-defined
28 programme types.
29
30 ``V4L2_CID_RDS_RX_PS_NAME (string)``
31 Gets the Programme Service name (PS_NAME). It is intended for
32 static display on a receiver. It is the primary aid to listeners in
33 programme service identification and selection. In Annex E of
34 :ref:`iec62106`, the RDS specification, there is a full
35 description of the correct character encoding for Programme Service
36 name strings. Also from RDS specification, PS is usually a single
37 eight character text. However, it is also possible to find receivers
38 which can scroll strings sized as 8 x N characters. So, this control
39 must be configured with steps of 8 characters. The result is it must
40 always contain a string with size multiple of 8.
41
42 ``V4L2_CID_RDS_RX_RADIO_TEXT (string)``
43 Gets the Radio Text info. It is a textual description of what is
44 being broadcasted. RDS Radio Text can be applied when broadcaster
45 wishes to transmit longer PS names, programme-related information or
46 any other text. In these cases, RadioText can be used in addition to
47 ``V4L2_CID_RDS_RX_PS_NAME``. The encoding for Radio Text strings is
48 also fully described in Annex E of :ref:`iec62106`. The length of
49 Radio Text strings depends on which RDS Block is being used to
50 transmit it, either 32 (2A block) or 64 (2B block). However, it is
51 also possible to find receivers which can scroll strings sized as 32
52 x N or 64 x N characters. So, this control must be configured with
53 steps of 32 or 64 characters. The result is it must always contain a
54 string with size multiple of 32 or 64.
55
56 ``V4L2_CID_RDS_RX_TRAFFIC_ANNOUNCEMENT (boolean)``
57 If set, then a traffic announcement is in progress.
58
59 ``V4L2_CID_RDS_RX_TRAFFIC_PROGRAM (boolean)``
60 If set, then the tuned programme carries traffic announcements.
61
62 ``V4L2_CID_RDS_RX_MUSIC_SPEECH (boolean)``
63 If set, then this channel broadcasts music. If cleared, then it
64 broadcasts speech. If the transmitter doesn't make this distinction,
65 then it will be set.
66
67 ``V4L2_CID_TUNE_DEEMPHASIS (enum)``
68 Configures the de-emphasis value for reception. A de-emphasis filter
69 is applied to the broadcast to accentuate the high audio
70 frequencies. Depending on the region, a time constant of either 50
71 or 75 microseconds is used. The enum v4l2_deemphasis defines possible
72 values for de-emphasis. They are:
73
74 .. flat-table::
75 :header-rows: 0
76 :stub-columns: 0
77
78 * - ``V4L2_DEEMPHASIS_DISABLED``
79 - No de-emphasis is applied.
80 * - ``V4L2_DEEMPHASIS_50_uS``
81 - A de-emphasis of 50 uS is used.
82 * - ``V4L2_DEEMPHASIS_75_uS``
83 - A de-emphasis of 75 uS is used.
84

3. 한국어 전문 번역

영어 원문의 문단 순서와 의미를 유지한 전체 번역입니다. 코드, 함수명, symbol과 URL은 원문 표기를 유지합니다.

FM_RX 클래스

1-20

FM 수신기(`FM_RX`) 클래스는 FM 방송을 수신할 수 있는 장치에 공통적인 기능을 제어합니다. `V4L2_CID_FM_RX_CLASS`는 이 클래스의 설명자이며 `VIDIOC_QUERYCTRL`로 조회하면 제어 클래스에 대한 설명을 반환합니다.

FM 수신 제어 흐름
수신 주파수에 튜너를 맞춤지역 규격에 맞는 de-emphasis 선택필요하면 RDS 수신 활성화PTY, PS 이름, RadioText와 교통 정보를 읽음

튜너가 복조한 방송 신호에서 음성과 RDS 부가 정보를 각각 구성합니다.

.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later

.. _fm-rx-controls:

*****************************
FM Receiver Control Reference
*****************************

The FM Receiver (FM_RX) class includes controls for common features of
FM Reception capable devices.


.. _fm-rx-control-id:

FM_RX Control IDs
=================

``V4L2_CID_FM_RX_CLASS (class)``
    The FM_RX class descriptor. Calling
    :ref:`VIDIOC_QUERYCTRL` for this control will

RDS 수신 정보

21-62

`V4L2_CID_RDS_RECEPTION`은 라디오 튜너의 RDS 수신을 켜거나 끕니다. `V4L2_CID_RDS_RX_PTY`는 미리 정의된 최대 31개 프로그램 유형을 나타내는 Programme Type 필드를 읽습니다.

`V4L2_CID_RDS_RX_PS_NAME`은 수신기의 정적 표시에 쓰는 Programme Service 이름을 읽습니다. 문자 인코딩은 IEC 62106 부속서 E를 따릅니다. PS는 보통 8자이지만 8 x N자 스크롤 문자열도 있으므로 제어의 step은 8자이고 문자열 길이는 항상 8의 배수여야 합니다.

`V4L2_CID_RDS_RX_RADIO_TEXT`는 방송 내용, 긴 PS 이름 또는 프로그램 관련 정보를 설명하는 RadioText를 읽습니다. 2A 블록은 32자, 2B 블록은 64자를 전달하며 스크롤 수신기는 32 x N 또는 64 x N자를 다룰 수 있습니다. 따라서 step과 실제 문자열 길이는 32 또는 64의 배수여야 합니다.

RDS 수신 제어
항목설명
`V4L2_CID_RDS_RECEPTION`RDS 수신을 활성화하거나 비활성화합니다.
`V4L2_CID_RDS_RX_PTY`최대 31개 유형의 Programme Type 값을 읽습니다.
`V4L2_CID_RDS_RX_PS_NAME`8자 단위의 Programme Service 이름을 읽습니다.
`V4L2_CID_RDS_RX_RADIO_TEXT`32자 또는 64자 단위의 방송 설명을 읽습니다.
`V4L2_CID_RDS_RX_TRAFFIC_ANNOUNCEMENT`현재 교통 안내가 진행 중이면 설정됩니다.
`V4L2_CID_RDS_RX_TRAFFIC_PROGRAM`현재 프로그램이 교통 안내를 제공하면 설정됩니다.

방송국이 송신한 서비스 식별 정보와 교통 상태를 읽습니다.

    return a description of this control class.

``V4L2_CID_RDS_RECEPTION (boolean)``
    Enables/disables RDS reception by the radio tuner

``V4L2_CID_RDS_RX_PTY (integer)``
    Gets RDS Programme Type field. This encodes up to 31 pre-defined
    programme types.

``V4L2_CID_RDS_RX_PS_NAME (string)``
    Gets the Programme Service name (PS_NAME). It is intended for
    static display on a receiver. It is the primary aid to listeners in
    programme service identification and selection. In Annex E of
    :ref:`iec62106`, the RDS specification, there is a full
    description of the correct character encoding for Programme Service
    name strings. Also from RDS specification, PS is usually a single
    eight character text. However, it is also possible to find receivers
    which can scroll strings sized as 8 x N characters. So, this control
    must be configured with steps of 8 characters. The result is it must
    always contain a string with size multiple of 8.

``V4L2_CID_RDS_RX_RADIO_TEXT (string)``
    Gets the Radio Text info. It is a textual description of what is
    being broadcasted. RDS Radio Text can be applied when broadcaster
    wishes to transmit longer PS names, programme-related information or
    any other text. In these cases, RadioText can be used in addition to
    ``V4L2_CID_RDS_RX_PS_NAME``. The encoding for Radio Text strings is
    also fully described in Annex E of :ref:`iec62106`. The length of
    Radio Text strings depends on which RDS Block is being used to
    transmit it, either 32 (2A block) or 64 (2B block). However, it is
    also possible to find receivers which can scroll strings sized as 32
    x N or 64 x N characters. So, this control must be configured with
    steps of 32 or 64 characters. The result is it must always contain a
    string with size multiple of 32 or 64.

``V4L2_CID_RDS_RX_TRAFFIC_ANNOUNCEMENT (boolean)``
    If set, then a traffic announcement is in progress.

``V4L2_CID_RDS_RX_TRAFFIC_PROGRAM (boolean)``
    If set, then the tuned programme carries traffic announcements.

``V4L2_CID_RDS_RX_MUSIC_SPEECH (boolean)``

음악 구분과 de-emphasis

63-83

`V4L2_CID_RDS_RX_MUSIC_SPEECH`가 설정되면 음악 방송이고 해제되면 음성 방송입니다. 송신기가 이 둘을 구분하지 않는 경우에는 설정된 상태로 전달됩니다.

`V4L2_CID_TUNE_DEEMPHASIS`는 수신 시 적용할 de-emphasis를 정합니다. 방송의 고음역을 보정하는 필터이며 지역에 따라 50 us 또는 75 us 시정수를 사용합니다.

De-emphasis 값
항목설명
`V4L2_DEEMPHASIS_DISABLED`De-emphasis를 적용하지 않습니다.
`V4L2_DEEMPHASIS_50_uS`50 us de-emphasis를 적용합니다.
`V4L2_DEEMPHASIS_75_uS`75 us de-emphasis를 적용합니다.

수신 지역과 송신 측 pre-emphasis 규격에 맞춰 선택합니다.

    If set, then this channel broadcasts music. If cleared, then it
    broadcasts speech. If the transmitter doesn't make this distinction,
    then it will be set.

``V4L2_CID_TUNE_DEEMPHASIS (enum)``
    Configures the de-emphasis value for reception. A de-emphasis filter
    is applied to the broadcast to accentuate the high audio
    frequencies. Depending on the region, a time constant of either 50
    or 75 microseconds is used. The enum v4l2_deemphasis defines possible
    values for de-emphasis. They are:

.. flat-table::
    :header-rows:  0
    :stub-columns: 0

    * - ``V4L2_DEEMPHASIS_DISABLED``
      - No de-emphasis is applied.
    * - ``V4L2_DEEMPHASIS_50_uS``
      - A de-emphasis of 50 uS is used.
    * - ``V4L2_DEEMPHASIS_75_uS``
      - A de-emphasis of 75 uS is used.