How can I configure the right Loop Filter component & Charge pump values?
My system is working at 2-3GHz
I need lock time of 100usec.
The values are stored in LUT tables. Please find files with LUTs attached.
I would recommend reading synthesizer related sections of AD9361 Reference Manual UG-570.
I have a question. In the file "SynthLUT_v2.zip", I don't know use column Band but If I want to config Rx freq 1710 MHz and Tx Freq 1805 MHz, what the row I will choose for config!
The drivers should correctly configure this portion too. "Band" column is not a parameter that needs to be set in the chip. It is information only.
To use the table, the RFPLL (Fvco) frequency is used to access the data in the corresponding row (FRFPLL=LO * 2^(VCO DIVIDER + 1)). For a given row, Fvco represents the lower frequency boundary for the row data (use data in the row when VCO frequency is equal to or greater than the frequency in the current row, but below the VCO frequency in the row above). For example, if the operating frequency is 800MHz, then Fvco=6400MHz according to (FRFPLL=LO * 2^(VCO DIVIDER + 1). For this frequency, data from row index 45 is used. The columns marked band, fref, loop bw, index and kv are informational to allow for readability. The other columns contain data that is retrieved, formatted by the user and then written into the device. Above the table, the upper column labels show the appropriate registers and bit positions for both RX and TX synthesizers in the format of Register Address (in HEX) followed by the bit positions (from bit7 to bit0).
Specific to this section, the VCO parameters are in the columns with ‘vco’ in the heading. The last 6 columns are for setting the charge pump current and loop filter for a specific configuration. The VCO parameters as provided by ADI should be pulled from the table and written into the device in the registers/positions indicated without modification. However the user can change charge pump and loop filter parameters to suit the particular application if desired.
Thank for your answer!
Thank you very much!
I found those tables already, another question on the same subject:
If say my LO is 2300 MHz, (freq BW 2-2.6 GHz) I can then calculate the Frfpll frequency (according to equation 1)
which would be: 9200 MHz, which is also my Fvco value.
Then I can go to the LUT tables, look for FDD/TDD 80MHz table and the row that is has the same or greater Fvco freq and choose the values of CP& Loop filter in that row, Am I right?
If I'm right, then another question : Lets say that the default values in the table are not satisfying...for example, I need to change the CP current, or get a faster lock time, or narrow loop. what then? obviously I need to change the component values in the filter, how can I do that?
We do not support device use in this forum via individual SPI writes due to the complexity.
The recommended approach is to use device drivers available at the link below:
AD9361 high performance, highly integrated RF Agile Transceiver™ Linux device driver [Analog Devices Wiki]
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