[USRP-users] USRP B210 GPS bias-tee Current Limit
What is the maximum current that the B210 provide to the GPS antenna?\ \ Is the biasing current provided by the GPSDO or via some onboard bias tee on the B210 PCB? Best regards, ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: USRP B210 GPS bias-tee Current Limit
Hi John, the B2x0 motherboard just connects the GPSDO's antenna pin to the SMA connector on the back of the board, directly [1, p1 J101]. So, the part you need to inspect for current capabilities here is the GPSDO. I don't have the exact numbers at hand right now, but assume up to at most 40 mA. Essentially, the GPSDO for these devices is a modification of the LC_XO fom Lackson Labs Technologies; its hardware properties would apply [2, p. 3]; I can't however not guarantee that it reaches the full 40 mA; I don't know whether that's a guaranteed property for how things play out as used in the USRP. What are you trying to power with this? This bias voltage is really only intended to drive an LNA, and owing to the sensitivity of the GPS receiver, such an LNA would not need much current. Best regards, Marcus [1] https://files.ettus.com/schematics/b200/b210.pdf [2] https://www.jackson-labs.com/assets/uploads/main/LC_XO_Manual.pdf On 18.03.24 08:24, johnhiggins...@gmail.com wrote: What is the maximum current that the B210 provide to the GPS antenna? Is the biasing current provided by the GPSDO or via some onboard bias tee on the B210 PCB? Best regards, ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: RFNOC Python API for timed GPIO
After spending some time, I arrived at the following conclusions (thanks also to Jonathon Pendlum): a) “set_command_time()” and “clear_command_time()” are available in Python API of UHD 4.6, also for RFNOC interface. b) The non-intuitive part is that, given the following sequence of commands: 1) radio_control_block.set_command_time(radio_control_block.get_time_now() + 10, 0) 2) COMMAND_A 3) radio_control_block.clear_command_time(0) 4) COMMAND_B will make COMMAND_A to be executed after 10 seconds and COMMAND_B just after COMMAND_A. The Radio block (and all RFNoC blocks in general) has only one command FIFO. When a timed command is sent, it is put in the block's command FIFO and all subsequent commands (timed or untimed) will be blocked by that timed command. In this sense, "clear_command_time()" has no effect. I hope this will be useful for other users. ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
