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SPORT Multichannel Mode -- RFS, DRx, sync at 1 mile

Question asked by ParaTech on Nov 4, 2011
Latest reply on Nov 8, 2011 by Prashant

Environment: Blackfin 52x, half duplex multichannel network, 32 bit words, 256K bits/sec, 16 transmit channels up to 1 mile distant from single receiver. Clock is transmitted from receiver to each transmit channel. Almost 360 deg. phase difference, or 1 bit /clock delay, from nearest to farthest transmitter.

 

I do not see any frame sync option to compensate for significant delay between received data and local receive frame sync, as the multichannel sequence progresses farther away from the receiver, and data delay approaches 1 bit or clock length. Is the only solution to equalize delays by designing a variable clock advance system to drive the transmit frame sync on each SPORT?

 

Hardware manual specifies that "All receiving and transmitting devices in a multichannel system must have the same timing reference." p. 24-19. It is further required that "both the transmitter and the receiver use RFS as a frame sync." id. This unrealistically assumes there is no propogation delay (distance, impedance) between channels.

 

Or, is the SPORT only intended for 128 multi-channels, all within 6 inches (10% delay) of each other? (200MHz wavelength = 4.92 feet, at maximum SPORT clock).

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