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TSW3085EVM: TSW 3085 EVC rev c TSW1266 rev a DAC3482 ADS5402

Part Number: TSW3085EVM
I have a question about using this platform.

I send samples WCDMA signal with 614.4Mhz sampling. on tsw308x I start from the Regs of the User's Guide of the TSW308x Evaluation Module with the NCO and QMC disabled. I do this so that the center frequency in the receiver is the same.

In the receiver I use the settings of the u User's Guide. And I analyze the NMSE of the received signal using MATLAB.

Using the example signal I achieved NMSEs better than -20 dB

I noticed that the sample signal is a signal multiplied by a cosine on channel 1 and by a sine on channel 2 and edited a similar signal, also reaching -20 dB of NMSE.

I tried to send a 4-QAM signal being the in-phase part in channel 1 and quadrature in channel 2. And in this way the NMSE got worse, reaching -7dB. Is it possible to send any type of signal using this platform, or does the signal in channel 2 have to be 90º out of phase, but equal to channel 1?
  • Hi,

    You may refer to the following app note for EVM% and ACPR performance:
    www.ti.com/.../slaa509.pdf

    We don't really measure NMSE here as none of the 3GPP spec really spells out NMSE. For the 4QAM performance, you may need to pulse shape your signal to improve the distortion performance of the signal chain (including your receiver chain) since the sampling domain may have Nyquist image cross over.

    -Kang