<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV>Gigabit PHYs are hot and can be noisy/ Ethernet is OK but not if it injects noise into the product. I'm the chief engineer for a single board rugged computer company serving the mil/aero market. Most of the problems I get involved with are EMI issues around the Ethernet interface and is almost always a layout issue with Ethernet PHY and signals going off board and out of box. If you do it be very careful. Good luck<BR></DIV>
<DIV>JimG - N1KWZ<BR><BR>Phil Harman wrote:<BR>> ***** High Performance Software Defined Radio Discussion List *****<BR>><BR>> All,<BR>><BR>> Having completed the Beta testing of Hermes we are now preparing to make<BR>> the necessary changes to bring the board into a production ready state.<BR>><BR>> There are quite a few changes which are mainly due to the fact we want to<BR>> ensure the product lives up to the 'High Performance' name tag.<BR>><BR>> One of the changes is to replace one of the high current linear regulators<BR>> with a SMPSU. We are fortunate to have Kjell, LA2NI, on our design team.<BR>> Kjell has designed a high frequency SMPSU that works well when<BR>> incorporated on the Hermes PCB and does not introduce significant spurs.<BR>> This substantially reduces the current drain and also the heat<BR>> dissipation.<BR>><BR>> The other potential change is this. I have this week
build a prototype<BR>> OzyII Gigabit Ethernet board. It works very well and I'm impressed with<BR>> how rugged Ethernet appears to be in comparison to USB and Firewire.<BR>><BR>> We therefore have the opportunity to replace the USB interface on Hermes<BR>> with Ethernet. There are a number of advantages in doing this:<BR>><BR>> - we overcome the USB driver issues when using different operating systems<BR>> - we can 'network attach' Hermes<BR>> - we will have a very high speed interface to the board for future features<BR>> - we can use a much longer Ethernet cable than USB allows<BR>><BR>> the disadvantages<BR>><BR>> - it may need more that one spin of the PCB which will delay the delivery<BR>> - we will use approximately 10% of the FPGA to implement the Ethernet<BR>> interface.<BR>><BR>> I'm not too concerned about using more of the FPGA since the device we are<BR>> using is 70% larger than
that used on Mercury.<BR>><BR>> So "to USB or not to USB - that is the question"?<BR>><BR>> 73's Phil...VK6APH<BR>><BR>><BR>><BR>> _______________________________________________<BR>> HPSDR Discussion List<BR>> To post msg: <A href="mailto:hpsdr@openhpsdr.org" ymailto="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</A><BR>> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org<BR>> HPSDR web page: http://openhpsdr.org<BR>> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/<BR>><BR>> <BR>_______________________________________________<BR>HPSDR Discussion List<BR>To post msg: <A href="mailto:hpsdr@openhpsdr.org" ymailto="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</A><BR>Subscription help: <A href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org" target=_blank>http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</A><BR>HPSDR web page: <A
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