Hello,

I use AD9361 designs these days, but I meet some problem.

I made the below frequency assignments in my system:

uint32_t Rx_clkfreq[6]={1280 000000, 80 000000, 80 000000, 80 000000, 40 000000, 40 000000};

uint32_t Tx_clkfreq[6]={1280 000000, 80 000000, 80 000000, 80 000000, 40 000000, 10 000000};

Accroding to the reference design in NO OS main.c:

uint32_t Rx_clkfreq[6]={786432000, 24576000, 12288000, 6144000, 3072000, 3072000};

uint32_t Tx_clkfreq[6]={786432000, 12288000, 12288000, 6144000, 3072000, 3072000};

There's some problems,

1)

Is it correct to use two differenct sample frequencies, 40M and 10M as above, for receving and transmitting at the same time?

2)

For the transmitting link,

I use a raised cosine FIR filter with fs=40 000000, -3dB frequnce point 5Mhz.

I send 10Mhz psedorandom +/- 512 series to stimulate the transmitt FIR input port.

Configurations:

1R1T FDD,

LVDS mode,

FPGA lvds port:

fb_clk: frequency 20Mhz

tx_frame: frequency 10Mhz

txd: 40Msps, ddr data flow with muxed Imsb,Qmsb, Ilsb, Qlsb

tx_lo_freq to 140Mhz,

And I wish I will get a raised cosine spetrum with 3dB-bandwith around 140Mhz.

The effect I need is:between each two 10Msps baseband +/-512 data point will be 3 inserted zeros, then the 4x interpolted 40MHZ data flow go into the 40Mhz-sample- rate rasied cosine FIR.

But I failed, the spectrum's outline is defined the by the raised cosine spetrum with 3dB-bandwith.

But the inner part is 2*5Mhz main sinc spectrum.

The effect seemed equals the 10Msps baseband +/-512 data flow has been decimated to 5Msps, and between each two none zero point, insert 7 zeros, then passed the 40Mhz sample rate rasied cosine FIR.

What's wrong?

Will you please give some advice?

Thanks in advance for your kindly help.

Micah

The spectrum on the left is needed.

The spectrum on the right is what I got.