Greetings
I am an owner of TSW3003 Evaluation Board
My objective is developing of DVB-S sistem based on FPGA and TSW3003
I have problems with DSC5687 configuration for QPSK.
Can You help me telling proper DAC5687 settings sequence for TSW3003 USB v1p1 (Texas Instruments default LabView - based software)?
Detailed description:
Digital part:
I have implemented in FPGA digital part of DVB-S system, including channel coding, mapper, upsampling and FIR RRC-Filter with roll-off factor 0.35%.
Symbol rate before mapper is 1064 kS/s (100MHz/47)
Data after FIR Filter is at 5MHz (two 16-bit channels with two's complement values of I and Q)
I have to use DAC5687 in "Interleave" mod, so I have 16 data wires and 2 control (QFLAG and PHSTR) wires (3.3V)
Finally, at the output of FPGA a have 10MHz-clockin 16data/2control signals for Gray-coded QPSK (Pi/4, 3Pi/4, 5Pi/4, 7Pi/4) modulation with ~0.35 roll-off factor.
TSW3003:
Quadrature modulator TRF3703 has no settings.
Frequency synthesizer TRF3761 is set to 2090MHz and /2 , to get 1045 MHz carrier, and it's ok.
CDCM7005 has a 491.52 VCXO frequency (and 10MHz reference frequency) - it's board defaults.
I should to use Interleave DAC mod with QFLAG to indicate A/B samlple.
At first, I want to get simplest DA-converted signal, without using any interpolation and mixing in DAC5687(Full Bypass option)
And I could not use PLL_LOCK out in External Clock Mode for driving input data suorce, it is required to use other synchronization methods for input data.
Which settings and in what order I should use for DAC5687 and CDCM7005 in TSW3003 USB v1p1 software, to get QPSK signal at the RF out of the board?
Best regards,
Alexander