TSW30SH84EVM: QMC phase is not working properly

Fuquan Wang

Part Number: TSW30SH84EVM

TSW1400EVM and TSW30SH84EVM are used to generate a 4QAM signal. The constellation plot is detected by a KeySight digital oscilloscope. However, the constellation is distorted and it is caused by quadrature error. In the TSW30SH84EVM GUI, I should be able to tune the phase using QMC phase. But this function does not work for me. Is additional setting required?

over 6 years ago

0 Kang Hsia over 6 years ago

TI__Guru* 78934 points

Hi Fuquan,

The QMC logic require synchronization to trigger the update. The easiest to perform is through SIF_SYNC. You can set CorrectAB SYNC source to be SIF SYNC, and then toggle the SIF_SYNC radio button at the lower left hand corner to update the value. We want to make sure the user is aware of the update as this is the TX side. Any update to the TX over the air must be controlled through proper trigger

There are other sync sources: refer to the following app note:

http://www.ti.com/lit/an/slaa584/slaa584.pdf section 3.

the QMC is an iterative approach. See below link section 8.7 for tips

http://www.ti.com/lit/ug/slwu029d/slwu029d.pdf

-Kang

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TSW30SH84EVM: QMC phase is not working properly