From: Nghia P. <ngh...@gm...> - 2011-08-18 19:07:08
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Thank you Robin. -----Original Message----- From: Robin Coxe [mailto:co...@cl...] Sent: Thursday, August 18, 2011 1:26 PM To: ope...@li... Subject: Re: [Openbts-discuss] RX and RX path of a burst Verilog looks a lot like C. Open the files and at least make an attempt to understand them before repeatedly posting the same question to this list. As stated in the README for the USRP FPGA design files, the USRP timestamp increments at the GSM symbol rate (270.83333 kHz). It is reset by issuing the ping command at OpenBTS initialization. This timestamp is generated by the Transceiver thread and is not the same thing as the GSM frame counter, as Thomas has explained. The answer is also in the in the inband-signaling-usb document. Read it again carefully: Timestamp: 32-bit timestamp. On IN packets, the timestamp indicates the time at which the first sample of the packet was produced by the A/D converter(s) for that channel. On OUT packets, the timestamp specifies the time at which the first sample in the packet should go out the D/A converter(s) for that channel. If a packet reaches the head of the transmit queue, and the current time is later than the timestamp, an error is assumed to have occurred and the packet is discarded. As a special case, the timestamp 0xffffffff is interpreted as "Now". So, unless the timestamp is 0xffffffff, packets are NOT pushed up the transmit chain as quickly as possible. --------------------------- From: nghia phan <ngh...@gm...> To: Robin Coxe <co...@cl...> Date: Wed, 17 Aug 2011 22:42:57 +0200 Subject: Re: [Openbts-discuss] RX and RX path of a burst Hi Robin, Thanks for the confirmation. :-( Unfortunately I don't know Verilog in order to jump into .v files (not yet...) . I only need to know if I and Q samples which arrive on GPIF data bus are pushed into the deinterleaver "as quickly as possible" or if they going through timing check or processing (like sorting, buffering, delaying, sync ..) before being pushed into the de-interleaver. My feeling is that they are pushed into the deinterleaver and then CIC filter "as quickly as possible". Would you agree? Thanks Nghia ---------------------------------------------------------------------------- -- Get a FREE DOWNLOAD! and learn more about uberSVN rich system, user administration capabilities and model configuration. Take the hassle out of deploying and managing Subversion and the tools developers use with it. http://p.sf.net/sfu/wandisco-d2d-2 _______________________________________________ Openbts-discuss mailing list Ope...@li... https://lists.sourceforge.net/lists/listinfo/openbts-discuss |