Other Parts Discussed in Thread: LMK04803
I am using DAC3482 to generate a 255MHz sinesoidal wave. My plan is to generate a 10MHz baseband signal and use the DAC3482 built-in mixer moving 10MHz to 255MHz.
DATACLK = 122.88MHz which comes from FPGA which is synced with data
DACCLK = 983.04MHz which comes from TI frequency synthesizer LMK04803.
The data related to frequency I delivered to corresponding registers are listed below:
1. Choose 16 interpolation.(I feel this should be 8, but when I set 8, the spurious rised.)
2. Shut-down FIFO. There is no sync and ostr signals providing to DAC.
3. 16-bit input mode(word wide).
4. MIXER_ENA and MIXER_GAIN are opened.
5. Choose CMIX and shut down NCO. CMIX mode choose Fs/4, means 983.04/4=245.76MHz.
6. Choose external reference CLK.
7. Shut down PLL.
8. Set current 20mA.
The whole data are listed below:
{0x00, 0xA810},
{0x01, 0x000E},
{0x02, 0xF062}, //mix_ena
{0x03, 0x7001},
{0x0C, 0x0400}, //qmc_gainI
{0x0D, 0x4400}, //qmc_gainQ
{0x10, 0x0000}, //phase
{0x14, 0x0000},
{0x15, 0x0000},
{0x18, 0x0000},
{0x1B, 0x8800},
{0x1E, 0x4200},
{0x1F, 0x4200},
{0x20, 0x1400},
{0x24, 0x0400},
{0x2D, 0x0004},
{0x30, 0x0000},
The there is a high spurious at 728MHz.