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Altera_Forum's avatar
Altera_Forum
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14 years ago

DAC/ADC not at full range.

I am using the THDB_ADA daughter card and the DE2-115. I am feeding an NCO output (2Vpp sine wave) from the DAC straight into the ADC through an SMA cable. However, the values registered by the ADC o...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

I reviewed the schematic, DAC output impedance is actually 100 ohm. When connecting it to a 50 ohm terminated input, the signal level is reduced to one third, very near the value you observed. Please don't ask me, why the DAC output has 100 ohm impedance ...