Hello, I use ad9361 to translate a sine wave, LVDS mode, FDD, SPI control.
Now, I use chipscope to compare the adc_data and dac_data. signal the blue is adc_data I received.
Can anyone tell me why it happend? any register is incorrect?
Since the TX is directly looped back to RX when you set 0X3F5 = 1. It should be fine.
Can you try the same using IIO scope? Below are the settings capture.
How is the setup ? What is the input power at Rx port ?
Are you using Evaluation board and looping back Tx to Rx . ? Try adding attenuation in Tx path and repeat the measurement.
I used to set 3F5[D0} = 1, then the Rx equal to Tx.
then I add attenuation in Tx path, but nothing changed.
Now the interface between RX1A and TX1A connected by a SMA, then the sine wave from the kc705 to AD9361, and looping back to RX.
tlili This problem trouble me for a long time. I need your help.
thank you very much!
I think you are trying to do loopback test using internal loopback from TX data port to RX data port.
What you configured is correct
0x3F4 = 0x1 to get the loop back samples.
What is the sampling rate and what is the tone frequency on TX?
Is it a custom hardware?
refer AD936x Built in Self Test (BIST) for details.
thank you for your reply.
yes, i am trying to do loopback(0x3f5=0x01) test, and receive the sine wave signal correctly.
when I set register 0x3f4 = 0x03, the receive signal is incorrect. It seems like a square wave.
The sine wave frequency is less than 1MHz on Tx, and the samplng rate is 245.76MHz(DAC, ADC),.
I used LTE10 standard, LVDS mode, FDD, 1R1T with KC705+AD9361, Reference CLK=40MHz.
This problem is solved now, it seems like the tx gain is not match.
Thank you all the same.
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