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xiangxufu's avatar
xiangxufu
Icon for New Contributor rankNew Contributor
5 years ago

IFFT

Dear sir, I encountered the following problems when using FFT IP core to simulate My FFT IP core configuration is as follows.I configure it as IFFT. In the case of entering the same data, ...
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CheepinC_altera's avatar
CheepinC_altera
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi,


Sorry for the delay. The case has just been routed to me. As I understand it, you observe some issue with the FFT IP in simulation. To ensure we are on the same page, just would like to check with you on the following:


1. What is the specific device and Quartus version that you are using?


2. Just would like to check with you if you have had a chance to try with "Variable Streaming" + "Fixed Point"?


3. Just would like to check with you if you have had a chance to try simulating with the IP generated example design to see if similar issue persists?


Please let me know if there is any concern. Thank you.


  • xiangxufu's avatar
    xiangxufu
    Icon for New Contributor rankNew Contributor
    5 years ago

    Hi,

    Thank you for you reply.

    My platform is bladeRF software radio, the chip is 5CEBA9F23C8, quartus version is 17.1, modelsim version is 10.6d.

    In a project, I use the following script command to compile the ifft file:
    1. vlog -vlog01compat -work nuand +incdir+G:/bladeRF/hdl/fpga/user/src/trans {G:/bladeRF/hdl/fpga/user/src/trans/ifft_top.v}
    2. vlog -vlog01compat -work nuand +incdir+G:/bladeRF/hdl/fpga/user/ip/trans/ifft/ifft/synthesis {G:/bladeRF/hdl/fpga/user/ip/trans/ifft/ifft /synthesis/ifft.v}
    3. vlog -sv -work nuand +incdir+G:/bladeRF/hdl/fpga/user/ip/trans/ifft/ifft/synthesis/submodules {G:/bladeRF/hdl/fpga/user/ip/trans/ifft /ifft/simulation/submodules/ifft_fft_ii_0.vo}
    4. vcom -93 -work nuand {G:/bladeRF/hdl/fpga/user/ip/trans/ifft/ifft/synthesis/submodules/auk_dspip_math_pkg.vhd}
    5. vcom -93 -work nuand {G:/bladeRF/hdl/fpga/user/ip/trans/ifft/ifft/synthesis/submodules/auk_dspip_lib_pkg.vhd}

    The following simulation results appear

    In another project, I used the following script command to compile the ifft file:
    1. vlog -vlog01compat -work work +incdir+G:/trans_sim_tx/user/src/trans {G:/trans_sim_tx/user/src/trans/ifft_top.v}
    vlib ifft
    vmap ifft ifft
    2. vlog -vlog01compat -work ifft +incdir+G:/trans_sim_tx/user/ip/trans/ifft/ifft/synthesis {G:/trans_sim_tx/user/ip/trans/ifft/ifft/synthesis/ifft.v}
    3. vlog -sv -work ifft +incdir+G:/trans_sim_tx/user/ip/trans/ifft/ifft/synthesis/submodules {G:/trans_sim_tx/user/ip/trans/ifft/ifft/simulation/submodules/ifft_fft_ii_0 .vo}
    4. vcom -93 -work ifft {G:/trans_sim_tx/user/ip/trans/ifft/ifft/synthesis/submodules/auk_dspip_math_pkg.vhd}
    5. vcom -93 -work ifft {G:/trans_sim_tx/user/ip/trans/ifft/ifft/synthesis/submodules/auk_dspip_lib_pkg.vhd}
    The following simulation results appear

    Through matlab simulation, confirm that the output of the second project is correct

    I think there is no difference between the two compilation processes. The data sent at the same time is the same, but the simulation results are different. What might cause such an abnormal situation.This is my problem.