有一个问题想请教一下， ADAR7251 datasheet 说支持FSK-FMCW 这种模式， 目前，我们想实现这种雷达波形的采数，请问ADAR7251在时序上如何实现较好？ 我详细描述如下
请问一下，如果用ADAR7521来实现, 硬件和ADAD7251配置上，如何做？ 十分感谢。
The reply from PL:
The ADAR7251 has DAQ mode for FSK application support. In this mode the CS (convert start) signal is used to initiate the conversion. The ADAR7251 samples the input and then outputs the Data Ready signal to indicate the conversion data is ready for output. The ADC data can be output either in serial or PPI mode along with the bit clock. Refer to Page 27 of the Datasheet .
There are 3 modes DAQ16/24/32. The DAQ 16 is fastest hence wider BW but lower resolution and DAQ32 will be higher resolution than DAQ16 but lower BW. The FFT's are included for reference in the TPC section for DAQ modes.
The conversion times for each of the modes are included in table 16. You may have to choose the mode based your Signal Flight time requirement ( transmit + receive) .
Based on the 5us FSK step I guess you could use either of the 3 modes. So effectively if you toggle the CS signal at 5us ( 200kHz) it becomes your sample rate in DAQ mode. Then you could achieve around 100kHz BW. I would recommend using DAQ32 for better resolution.
The register 0x143 is for DAQ mode. You would need to select the data output rate depending on the DSP.
Also please note in DAQ mode the ADC will wait for CS signal and sample the input only when CS is pulled low.