Changes between Version 35 and Version 36 of Internal/BuildingGNURadioImage

Timestamp:

Mar 11, 2009, 10:49:20 PM (15 years ago)

Author:

ssugrim

Comment:

—

Internal/BuildingGNURadioImage

@@ -609 +609 @@
 and we saw :
 
-[[Image()]]
-
+[[Image(usrp-gmsk-250kbps-fft.JPG)]]
+
+To actually "recieve" the sginal we did:
+
+{{{
+node1-2:~/gnuradio/gnuradio-examples/python/digital# ./benchmark_rx.py -f 5M -r 125k -R A -v
+>>> gr_fir_fff: using SSE
+bits per symbol = 1
+M&M clock recovery omega = 2.000000
+M&M clock recovery gain mu = 0.175000
+M&M clock recovery mu = 0.500000
+M&M clock recovery omega rel. limit = 0.005000
+frequency error = 0.000000
+
+Receive Path:
+Using RX d'board A: Basic Rx
+Rx gain:         10
+modulation:      gmsk_demod
+bitrate:         125kb/s
+samples/symbol:    2
+decim:           256
+Rx Frequency:    5M
+ok =  True  pktno =    1  n_rcvd =    1  n_right =    1
+ok =  True  pktno =    2  n_rcvd =    2  n_right =    2
+ok =  True  pktno =    3  n_rcvd =    3  n_right =    3
+ok =  True  pktno =    4  n_rcvd =    4  n_right =    4
+ok =  True  pktno =    5  n_rcvd =    5  n_right =    5
+ok =  True  pktno =    6  n_rcvd =    6  n_right =    6
+ok =  True  pktno =    7  n_rcvd =    7  n_right =    7
+ok =  True  pktno =    8  n_rcvd =    8  n_right =    8
+}}}
+
+''' Note the drop in rate (-r 125k), we had to do this to prevent over runs on the receiver(uOuOuOuOuOuOuOu)'''
+
+The sender was passed:
+{{{
+node1-1:~/gnuradio/gnuradio-examples/python/digital# ./benchmark_tx.py -f 5M -r 125k -T A -v
+>>> gr_fir_fff: using SSE
+bits per symbol = 1
+Gaussian filter bt = 0.35
+Using TX d'board A: Basic Tx
+Tx amplitude     12000
+modulation:      gmsk_mod
+bitrate:         125kb/s
+samples/symbol:    2
+interp:          512
+Tx Frequency:    5M
+.................................................
+}}}
+
+to ship out packets. 
+
+----
+
+Bobs notes on over/under runs:
+uU:  The [u]srp is experiencing an [U]nderrun.  This only occurs on the receiver, and means we are dropping/missing data.
+uO:  The [u]srp is experiencing an [O]verrun.  This only occurs on the transmitter, and means we are not getting data to the transmitter fast enough.
+Most often, these errors are due to USB bus limitations.  Keep in mind that there is a single USB interface from the node to the USRP, 
+so it needs to be shared between the transmitter and receiver.
+
+