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#1 2015-Nov-11 22:45:49

severinwu
Member
Registered: 2013-Apr-08
Posts: 4

OFDM reference design - transmit & receive data by analog board

Hello, everyone

I'm working out with changing OFDM reference design, let the signal out from one analog board to another analog board(using two warp boards)

I know the signal out from the ofdm_txrx_mimo block tx_anta_dac_i & q is 16 bits

so I changed the ofdm_txrx_mimo model, let the output bit of tx_anta_i & q to be 14 bits (0:13)

and regenerate the pcore, replace the original pcore (in XPS folder),  disable(by comment the code) the original port (to radio bridge)

and connect the port to analog bridge, here is the code I changed in system.mhs :

Code:

ofdm_agc_mimo_plbw
# PORT i_out_a = ofdmRx_antA_ADC_I			#disable
# PORT q_out_a = ofdmRx_antA_ADC_Q			#disable

radio_bridge
# PORT user_DAC_I = radio_bridge_slot_2_user_DAC_I        	        #disable
# PORT user_DAC_Q = radio_bridge_slot_2_user_DAC_Q			#disable

analog_bridge
# PORT user_DAC1_A = ofdm_rx_debug_eq_i     	                  #original connected port
# PORT user_DAC1_B = ofdm_rx_debug_eq_q     	          #original connected port
PORT user_DAC1_A = analog_bridge_slot_4_user_DAC1_A		 	# change to ofdm tx anta i
PORT user_DAC1_B = analog_bridge_slot_4_user_DAC1_B		 	# change to ofdm tx anta q
PORT user_ADC_A = ofdmRx_analog_ADC_I			  # let output data to ofdm rx
PORT user_ADC_B = ofdmRx_analog_ADC_Q			  # let output data to ofdm rx

ofdm_txrx_supermimo_coded_plbw
PORT rx_anta_adci = ofdmRx_analog_ADC_I			# change the signal input from analog bridge
PORT rx_anta_adcq = ofdmRx_analog_ADC_Q			# change the signal input from analog bridge
# PORT tx_anta_dac_i = radio_bridge_slot_2_user_DAC_I			#disable
# PORT tx_anta_dac_q = radio_bridge_slot_2_user_DAC_Q			#disable
PORT tx_anta_dac_i = analog_bridge_slot_4_user_DAC1_A			# change to analog bridge
PORT tx_anta_dac_q = analog_bridge_slot_4_user_DAC1_B			# change to analog bridge
# PORT rx_debug_eq_i = ofdm_rx_debug_eq_i       		                #disable
# PORT rx_debug_eq_q = ofdm_rx_debug_eq_q					#disable

then when I export to SDK and program FPGA to WARP board, it is not work, and there is no signal out from the analog board

I found the signal received from radio board, the data will go to rate change filter block, then to the agc block, then finally to ofdm_txrx_mimo block

I guess the signal frequency would be the problem that i cant ping the board each other


I want to know if I change the signal from analog bridge to rate change filter block then go to the ofdmRx_analog_ADC_I & Q

Would this change will work ?  Or there are more things I need to considerate if i want to ping the board using analog board


Thanks for your help :)

Last edited by severinwu (2015-Nov-12 01:04:49)

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#2 2015-Nov-12 12:44:52

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: OFDM reference design - transmit & receive data by analog board

The OFDM Reference Design runs the Radio Board's ADCs/DACs at 40MSps. The OFDM PHY operates at 10MSps. The rate_change_filters block implements the 4x interpolation/decimation filters which adapt the 10MSps PHY interface to the 40MSps analog converter interfaces. If you want to use the Analog Board converters at 40MSps you should use the same rate_change_filter setup to implement the required interpolation/decimation.

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