ADRV9026 Dynamic slicer

  • The dynamic slicer is a slicer methodology that is distinct from the GPIO based slicer or the embedded slicer mode. The slicer, whether dynamic or static, is used with the digital gain compensation feature within the receiver. Like the embedded slicer mode, the slicer position is represented by replacing data bits within the JESD data word with slicer data. However, unlike the embedded slicer mode, the dynamic slicer does not permanently occupy positions within the JESD data word. The dynamic slicer allows the receiver to transmit the full data word to the baseband processor unless the slicer word needs to be transmitted to the baseband processor.
  • In Dynamic slicer mode, the user can either embed the SLICER bit at the MSB or the LSB. This can be done using the enum ADI_ADRV9025_EMBED_1_SLICERBIT_AT_MSB or ADI_ADRV9025_EMBED_1_SLICERBIT_AT_LSB part of the adi_adrv9025_RxSlicerEmbeddedBits_e enum set in the adi_adrv9025_RxDynamicSlicerConfig_t structure. Please note that dynamic slicer only supports these two embedded bit modes of operation (ADI_ADRV9025_EMBED_1_SLICERBIT_AT_MSB or ADI_ADRV9025_EMBED_1_SLICERBIT_AT_LSB). A diagram of the slicer bit position for the two cases is shown below –
    • At the LSB of the data word –

 

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    • At the MSB of the data word –

Please note that the use of signed magnitude data for the dynamic slicer is allowed in both MSB and LSB formats. However, two’s complement data can only be used when the data is at the LSB. Additionally, the dynamic slicer can be used in 12-bit operation modes. The user can refer to ‘Dynamic Slicer Bit Location’ section in the ADRV9026 Dynamic Slicer user guide available on RadioVerse for additional details.

  • The dynamic slicer packet is sent when a gain change occurs. This packet is composed of three segments for a total of 56-bits:
    • CRC8 result of 16-bit user data (8-bits)
    • Slicer Word Data (16-bits)
    • The Sync Header (32-bits)
  • The format for transmitting this packet is CRC word first, followed by the slicer word and finally the Sync Header. We cannot modify the packet transmission such that Sync Header is sent first. The user can use the SYNC header to check if the received frame has the dynamic slicer word or not. A snapshot of the dynamic packet transmission is shown below –

Note that each segment is transmitted on both I and Q data samples. Also, since the dynamic slicer packet is transmitted over multiple samples, sometime is taken to transmit the entire word. In the case above, the data rate is 245.76 MSPS. This data rate requires 114 ns to transmit the entire dynamic slicer packet.

  • During transmission of the Slicer Word Data (16-bits) in the middle of the packet transmission as shown above, slicer bits are transmitted first followed by the zeroes (shown below):

As this is hardware restriction we cannot change this transmission such that zeroes are transmitted first followed by slicer bits. The user is expected to use this format and extract the slicer bits accordingly.



Corrected the earlier response
[edited by: adrv9026_support at 5:19 PM (GMT 0) on 10 Jan 2020]