EN 50067 "Specification of the radio data system (RDS) for > +VHF/FM sound broadcasting in the frequency range from 87,5 to 108,0 MHz"

> + FM Transmitter Control Reference > + > + The FM Transmitter (FM_TX) class includes controls for common features of > +FM transmissions capable devices. Currently this class include parameters for audio > +compression, pilot tone generation, audio deviation limiter, RDS transmission and > +tuning power features. > + > + > + FM_TX Control IDs > + > + > + > + > + > + > + > + > + > + > + ID > + Type > + Description > + > + > + > + > + > + V4L2_CID_FM_TX_CLASS > + class > + The FM_TX class > +descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a > +description of this control class. > + > + > + V4L2_CID_RDS_ENABLED > + boolean > + > + Enables or disables the RDS transmission feature. > + > + > + V4L2_CID_RDS_PI > + integer > + > + Sets the RDS Programme Identification field > +for transmission. > + > + > + V4L2_CID_RDS_PTY > + integer > + > + Sets the RDS Programme Type field for transmission. > +This coding of up to 31 pre-defined programme types. coding -> encodes > + > + > + V4L2_CID_RDS_PS_NAME > + string > + > + Sets the Programme Service name (PS_NAME) for transmission. > +It is intended for static display on a receiver. It is the primary aid to listeners in programme service > +identification and selection. The use of PS to transmit text other than a single eight character name is not permitted. > + > + > + V4L2_CID_RDS_RADIO_TEXT > + string > + > + Sets the Radio Text info for transmission. It is a textual description of > +what is being broadcasted. If broadcaster wishes to transmit longer PS names, programme-related information or any other > +text, then RadioText should be used. This is slightly ambiguous. I would suggest changing the ending to: "should be used in addition to V4L2_CID_RDS_PS_NAME." > + > + > + V4L2_CID_AUDIO_LIMITER_ENABLED > + boolean > + > + Enables or disables the audio deviation limiter feature. > +The limiter is useful when trying to maximize the audio volume, minimize receiver-generated > +distortion and prevent overmodulation. > + > + > + > + V4L2_CID_AUDIO_LIMITER_RELEASE_TIME > + integer > + > + Sets the audio deviation limiter feature release time. > +The unit, step and range are driver-specific. I thought the unit was useconds? > + > + > + V4L2_CID_AUDIO_LIMITER_DEVIATION > + integer > + > + Configures audio frequency deviation level in Hz. > +The range and step are driver-specific. > + > + > + V4L2_CID_AUDIO_COMPRESSION_ENABLED > + boolean > + > + Enables or disables the audio compression feature. > +This feature amplifies signals below the threshold by a fixed gain and compresses audio > +signals above the threshold by the ratio of Threshold/(Gain + Threshold). > + > + > + V4L2_CID_AUDIO_COMPRESSION_GAIN > + integer > + > + Sets the gain for audio compression feature. It is > +a dB value. The range and step are driver-specific. > + > + > + V4L2_CID_AUDIO_COMPRESSION_THRESHOLD > + integer > + > + Sets the threshold level for audio compression freature. > +It is a dB value. The range and step are driver-specific. > + > + > + V4L2_CID_AUDIO_COMPRESSION_ATTACK_TIME > + integer > + > + Sets the attack time for audio compression feature. > +It is a useconds value. The range and step are driver-specific. > + > + > + V4L2_CID_AUDIO_COMPRESSION_RELEASE_TIME > + integer > + > + Sets the release time for audio compression feature. > +It is a useconds value. The range and step are driver-specific. > + > + > + V4L2_CID_PILOT_TONE_ENABLED > + boolean > + > + Enables or disables the pilot tone generation feature. > + > + > + V4L2_CID_PILOT_TONE_DEVIATION > + integer > + > + Configures pilot tone frequency deviation level. Unit is > +in Hz. The range and step are driver-specific. > + > + > + V4L2_CID_PILOT_TONE_FREQUENCY > + integer > + > + Configures pilot tone frequency value. Unit is > +in Hz. The range and step are driver-specific. > + > + > + V4L2_CID_PREEMPHASIS > + integer > + > + Configures the pre-emphasis value for broadcasting. > +A pre-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 useconds is used. The enum v4l2_fm_tx_preemphasis > +defines possible values for pre-emphasis. Here they are: > + > + > + > + > + V4L2_FM_TX_PREEMPHASIS_DISABLED > + No pre-emphasis is applied. > + > + > + V4L2_FM_TX_PREEMPHASIS_50_uS > + A pre-emphasis of 50 uS is used. > + > + > + V4L2_FM_TX_PREEMPHASIS_75_uS > + A pre-emphasis of 75 uS is used. > + > + > + > + > + > + > + V4L2_CID_TUNE_POWER_LEVEL > + integer > + > + Sets the output power level for signal transmission. > +Unit is in dBuV. Range and step are driver-specific. > + > + > + V4L2_CID_TUNE_ANTENNA_CAPACITOR > + integer > + > + This selects the value of antenna tuning capacitor > +manually or automatically if set to zero. Unit, range and step are driver-specific. > + > + > + > + > +

> + > +For more details about RDS specification, refer to > + document, from CENELEC. > +