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oresat / oresat-c3-hardware

C3 (Command, Communication, and Control) our Command and Data Handling (C&DH) card.
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Investigate AX5043 RX/TX matching circuit at UHF radio #48

Closed zisi closed 1 year ago

zisi commented 1 year ago

Hi, i would like to ask about the matching circuit in balanced and unbalanced lines in the AX5043. In both cases at 436.5MHz your design is different for the proposed design in datasheet. How you calculate these L-C values? For example in TX the C65 and L139 and in RX the BaLun L11,C58,C59 and L10(+L12), how you calculate, which is the input/output impedance of AX5043 at ~430MHz?

Thanks

zisi commented 1 year ago

According to this, i understand that you do not need the load network for internal differential PA, because you use the differential path only as RX, like this application note. So you need only a BalUn, with input balanced impedance 100Ohm to unbalanced 50Ohm. I'm not sure about the usage of L12.

zisi commented 1 year ago

Hi, there: https://gitlab.com/librespacefoundation/pq9ish/pq9ish-comms-vu-hw/-/issues/6#note_1141997003 you can find an analysis to reduce parts for RX and TX paths. I think we can close the issue.

Thanks to have your project open and share your knowledge about RF.

andrewgreenberg commented 1 year ago

OK! Closing!