Hello all:

Is there some limits that the sample rate can't set higher than 8Mhz when using QAM encoder of AD9789?

Thanks in advance

xu

Hello all:

Is there some limits that the sample rate can't set higher than 8Mhz when using QAM encoder of AD9789?

Thanks in advance

xu

Thanks for your reply,And I want to use AD9789 to finish QPSK in DVB 16-QAM mode,When I set the sample rate higher than 8MHz,I found it began to lose some data.My configuration is as the list:fDAC=1884.16MHz,sample rate=8MHz(I have tested with oscilloscope).I bypass the SRRC and one of Half-Band Interpolation Filters,then I have tried many delay value,but the problem didn't solve.

I wonder that there is some limits in QAM encoder,becouse I see some standard the QAM encode rate is always lower than 8MHz,

does AD9789's QAM encoder have the same limits?

By my calculations, your input data rate of 8 MHz is too high. Based on the 1884.16 MHz DACCLK and 16x + 4*2x interpolation, your data rate should be 7.36 MHz. Please try that and see if you still lose data, or increase your DACCLK to 2.048 MHz.