2.7.5.1 Modulation Settings

RF Frequency

The ATA8510/15 supports transmission in the following RF frequency bands:

Low-Band 310 MHz to 318 MHz
Low-Band 418 MHz to 477 MHz
High-Band 836 MHz to 956 MHz

For each service, there are three channels that can have different RF frequency settings. All channels within one service must be configured to the same frequency band. If the channels differ by more than a certain amount, a VCO tuning process is required during the start-up of this service/channel configuration (see VCO Tuning).

The RF frequency can be configured independently for each channel of each service in the EEPROM variables eepServices.FFREQ[2:0], eepServices.FEMS and eepServices.FECT (see Channel-Specific Configuration).


Address Ser0/Ch0	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0x0139	FFREQ[0]	FFREQL[7:0]
0x013A	FFREQ[1]	FFREQM[7:0]
0x013B	FFREQ[2]	FFREQH[7:0]
0x013C	FEMS	PLLM[3:0]				PLLS[3:0]
0x013D	FECR	—	—	ANPS	PLCKG	ADHS	ANDP	S4N3	LBNHB

RF Modulation

The ATA8510/15 supports the typical modulation types ASK and FSK for short-range device applications.

The ASK mode is implemented as pure on-off keying (OOK). The power amplifier is switched off at a logic ‘0’ and switched on at a logic ‘1’ of the modulation data signal. The transmitted carrier frequency corresponds to the FFREQ[2:0] variable setting of the active channel. An ASK-shaping filter can be activated for smooth up-ramping and down-ramping of the power amplifier. (For more information, see ASK Shaping Filter.)

In the FSK mode, the power amplifier is constantly on. The modulation data signal switches between two frequencies. FSK deviations are allowed in a wide range from approximately ±0.375 kHz to ±93 kHz. The PLL loop bandwidth is 50 kHz, limiting the transmission data rate to 20 Kbit/s Manchester or 40 Kbit/s NRZ. To achieve higher data rates, a digital pre-emphasis filter must be enabled (see Pre-Emphasis Filter). The spectral efficiency of the FSK transmission signal can be improved by activating a digital Gaussian shaping filter. (For more information, see Gaussian Shaping Filter.)

The modulation type can be configured independently for path A and path B of each service in the eepServices.txSetPathx[1].TXMODx variables.


Address Service0	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0x0102	txSetPathA[1]	TXMODA	ASKshapingenable	—	StartPreambleFillLevelA[4:0]
0x0104	txSetPathB[1]	TXMODB	ASKshapingenable	—	StartPreambleFillLevelB[4:0]

FSK Deviation

The ATA8510/15 can generate FSK deviations from approximately ±0.375 kHz to ±93 kHz. The FSK deviation can be configured independently for path A and path B of each service in the eepServices.txDevx[1:0].txDevx[15:0] variables.


Address Service0	Name	Bit 7
0x00D3	txDevA[0]	txDevA[7:0]
0x00D4	txDevA[1]	txDevA[15:8]
0x00D5	txDevB[0]	txDevB[7:0]
0x00D6	txDevB[1]	txDevB[15:8]

Data Rates

The TX modulator can generate symbol rates from 0.5 Ksym/s to 160 Ksym/s in the buffered mode. To compensate for the PLL loop filter bandwidth, the pre-emphasis filter has to be enabled for FSK modulation with data rates above 40 Ksym/s.

The data rate clock is generated by a timer that runs on a XTO/4 clock at around 6 MHz. The resulting data rate accuracy depends on the selected data rate, as shown in the following figure.

The data rate can be configured independently for path A and path B of each service in the eepServices.TXDRx[1:0].TXDRx[15:0] variables.


Address Service0	Name	Bit 7
0x00FD	TXDRA[0]	TXDRA[7:0]
0x00FE	TXDRA[1]	TXDRA[15:8]
0x00FF	TXDRB[0]	TXDRB[7:0]
0x0100	TXDRB[1]	TXDRB[15:8]

Note: The data rate configuration is only effective in TXMode(buffered). In TXMode(transparent), the serial data stream must be provided with the correct data rate by the external host on pin PC4/TMDI.

Data Coding

The ATA8510/15 supports NRZ and Manchester coding in TXMode(buffered). General information about Manchester coding can be found in NRZ and Manchester Coding. If Manchester coding is selected, only the data from the data FIFO and the CRC are Manchester-coded. Desync, data from the SFIFO preamble FIFO and the stop sequence are transmitted symbol-based.

The coding type can be configured independently for path A and path B of each service in the eepServices.TMCR2x.TMNRZE variables.


Address Service0	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0x0126	TMCR2A	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE
0x0127	TMCR2B	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE

Note: The data coding configuration is only effective in TXMode(buffered). In TXMode(transparent), the serial data stream must be provided correctly coded by the external host on pin PC4/TMDI.

Data Polarity

The TX Modulator can switch the polarity of the transmission data in TXMode(buffered). This is done by inverting the serial data stream at the output of the TX modulator after the Manchester coder. Depending on the modulation and coding settings, this results in a different data stream, as shown in the following figure. The polarity setting affects the entire data stream, consisting of data from the SFIFO, DFIFO, CRC generator and the stop sequence.

The data polarity can be configured independently for path A and path B of each service in the eepServices.TMCR2x.TMPOL variables.


Address Service0	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0x0126	TMCR2A	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE
0x0127	TMCR2B	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE

Note: The polarity configuration is only effective in TXMode(buffered). In TXMode(transparent), the serial data stream must be provided correctly coded by the external host on pin PC4/TMDI.

Data Order

The TX modulator can switch the order of the data from the DFIFO in TXMode(buffered) between LSB-first and MSB-first. The default setting is LSB-first. If MSB-first is selected, the order of each byte is switched before transmission. The data order setting only affects data taken directly from the DFIFO. Data from the SFIFO, CRC and stop sequence are always transmitted MSB-first.

The data order can be configured independently for path A and path B of each service in the eepServices.TMCR2x.TMMSB variables.


Address Service0	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
0x0126	TMCR2A	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE
0x0127	TMCR2B	—	TMMSB	TMSSE	TMPOL	TMNRZE	TMCRCL[1:0]		TMCRCE

Note: The data order configuration is only effective in TXMode(buffered). In TXMode(transparent), the serial data stream must be provided correctly coded by the external host on pin PC4/TMDI.