17-11-2018, 04:05 PM
Hi Jeffrey
Thank you, I was surprised how well the carrier looked after the low pass filter.
You are right I did start with the higher clock frequency and then divided it down for the pixel frequency. Reading back I can see that what I wrote inferred the other way round.
I am using a multiplier core for the modulation 9 bit video and 14 bit carrier with the output truncated to 14 bits. Also just doing X 4 oversampling for now will do X 20 later.
The output circuit of the DAC at the moment is unbalanced just using the working -ve output. I have another AD9744 (hope it is not duff too). I will fit it and try the balanced to unbalanced circuit you suggested.
Some not so good photos of the board I am using.
Frank
Thank you, I was surprised how well the carrier looked after the low pass filter.
You are right I did start with the higher clock frequency and then divided it down for the pixel frequency. Reading back I can see that what I wrote inferred the other way round.
I am using a multiplier core for the modulation 9 bit video and 14 bit carrier with the output truncated to 14 bits. Also just doing X 4 oversampling for now will do X 20 later.
The output circuit of the DAC at the moment is unbalanced just using the working -ve output. I have another AD9744 (hope it is not duff too). I will fit it and try the balanced to unbalanced circuit you suggested.
Some not so good photos of the board I am using.
Frank
