frequency range of ADA HSMC daughter board for Cyclone III FPGA

Dear everyone,

I am Peipei, I am using HSMC ADA daughter board with Cyclone III FPGA. I have generated a range of frequencies from 1KHz to 2MHz from the HSMC board via Cyclone III FPGA board (using VHDL). But I cannot receive good results of low frequencies at all. When I double check the schematic diagram of this daughterboard, I surprisedly found there are transformers connected to ADCs and DACs. So may I assert that the AD/DA board used as a high-pass filter? If it is, it will be a horrible news for me due to I need generate a range of low frequencies. But IS THERE ALTERNATIVE WAY that I can deal with it? Say, is there similar daughterboard I can use and without work as high-pass filter? Or how can I manually change the board?

According to the example .exe program the company offered in the example folder, it does shows the feature is bad performance of low frequencies.

I am really looking forward to hear from you.

Thank you very much.

Best wishes,

peipei