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5227 Discussions

Possible low frequency (<400kHz) capability on the THDB_ADA board?

Altera_Forum
Honored Contributor II
909 Views

I know there is a way to desolder a transformer on the DAC part of the THDB_ADA board, to achieve low frequency single ended output. 

 

Can a similar thing be done to the ADC circuitry in order to achieve ADC capability down to about 20-30 Hz? 

 

Thank you.
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5 Replies
Altera_Forum
Honored Contributor II
168 Views

I suggest to refer to the AD9248 datasheet for possible solutions. There's an option to use the ADC in single ended configuration, although it involves a certain performance degradation. It would need an additional voltage divider bypassing the +input to Vcc/2 and a large input coupling capacitor, e.g. 10 µF ceramics. 

 

My personal favourite is a DC capable fully differential amplifier as single ended to differential converter, as used in the AD9248 evaluation board, the schematic is also included in the datasheet.
Altera_Forum
Honored Contributor II
168 Views

can you guide me how to desolder a transformer on the DAC and ADC part . How to solder a new transformer ?? 

Did you find any solution for the low frequency range. I am trying to load a 100 Hz signal into the ADC.
Altera_Forum
Honored Contributor II
168 Views

There are no suitable transformers to be used instead of the RF transformer. 

 

A simple modification could be made like below, needing an input Signal with DC Offset. 

 

https://www.alteraforum.com/forum/attachment.php?attachmentid=11278
Altera_Forum
Honored Contributor II
168 Views

I am using a Stratix III DSP development board. Our HSMC AD/DA data conversion card consists of MCL 045 transformer of TT1-6 for each ADC and DAC. For this transformer what modification is required for low frequency input ?

Altera_Forum
Honored Contributor II
168 Views

What is the modification needed for the DAC?

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