• TI Thinks Resolved

TRF371125: Amplitude and phase balancing

Expert 6030 points

Replies: 4

Views: 94

Part Number: TRF371125

Hi Team,

A customer wants to know the amount of amplitude and phase balancing of TRF371125. 

Regards,

Danilo

  • Hello Danilo,

    There is no direct way to measure gain and phase imbalance within the TRF371125 down-conversion process. The gain/phase imbalance of the in phase (I) and quadrature (Q) are inherent analog design mismatch, and can be directly represented as sideband image suppression and DC offset suppression.

    You may refer customer to Figure 41 (image rejection vs. baseband frequency) and Figure 42 (DC offset vs. temperature) for the inherent suppression of the two artifacts. The customer may correct this within their baseband processing within the FPGA/ASIC.

    -Kang

  • In reply to Kang Hsia:

    That' too bad.

    Amplitude and Phase imbalances are very important characteristics.

    You may know your compatotor Analog Devices. ADL5380 is one alternative.

    ADI provide sufficient information of these characteristics.

    Hope to provide them as soon as possible.

  • In reply to Jeong Phill Kim:

    Danilo:

    Kang is correct.  Amplitude and phase imbalance will manifest as sideband rejection degradation.  Isolating the specific amplitude and phase parameter is inherently not too useful as it is the sideband rejection performance that limits system performance.  Figure 41 in the datasheet illustrates the sideband rejection performance which is around 40 dB.

    You can get a range of the independent amplitude and phase imbalance by looking at constant cancellation curves like the graph below.  For a 40 dB sideband rejection, you follow the red curve.  The red curve can have a max +/- 0.1 dB amplitude mismatch  (with 0 deg phase error) and a max 0.5 degree phase mismatch (with 0 dB amplitude error).  Note, these max values do not happen simultaneously as that would translate to a worse sideband rejection.  Most of the error is budgeted to the phase.  Generally there is only about 0.02 dB of amplitude error and 0.4 to 0.5 deg of phase error.

    --RJH

  • In reply to RJ Hopper:

    OK. Thank you very much for your clear explanation.

    Thank you.