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Altera_Forum
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13 years ago

Dac help needed to generate sine waveform from Altera FPGA

Hi, My application needs to generate a sine wave of 10 to 20 samples per period. I am using Altera Cyclone 3 FPGA. Can anyone suggest which DAC I should be using. Also inputs as to how to go ab...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Hello,

I did a bit of research and I have decided for the initial part to use a lookup table and input the values to the DAC. I dont intend to implement a DDS at the very beginning. The frequency of the sine wave is going to be around 60Mhz and I will be using a 14bit DAC from Terasic (The one which is compatible to Altera Cyclone 3 FPGA starter kit with HSMC connector). I need to know how many samples will be ideal per cycle for a fairly clean sinwave to be seen at the scope . Also to represent the negative part of the sine wave, I must use 2's complement representation. Will the DAC take that into account? I mean if I represent a number in 2's complement form will the DAC understand that or take that as a positive number? Also say I have the magnitude of sine wave at a particular time to be 0.4583. If I multiply it by 1000 and store 4583 as shown in many posts, how will the DAC know that it has to represent 0.4583 and not 4583, or is it the relative values that are taken into account by the DAC? If someone can address these doubts, I would be very thankful.

Regards,

Ranjan