Rita » History » Version 4
laforge, 02/19/2016 10:48 PM
add scope captures from the I/Q baseband output
1 | 4 | laforge | [[PageOutline]] |
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3 | = TRF6151C = |
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4 | 1 | laforge | This is the Texas Instruments RF Chip TRF6151C |
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6 | It includes a VCO, Mixers, etc. |
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7 | 2 | laforge | |
8 | == TSP == |
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9 | |||
10 | The TSP to the TRF6151 uses three wires: |
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11 | * CLOCK (regular CLK_13M) |
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12 | * STROBE (generated by TPU) |
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13 | * DATA (provided by TPU at falling edge of CLOCK, TRF samples data at rising edge of CLOCK) |
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14 | |||
15 | [[Image(Rita:trf6151_serial_1.png)]] |
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16 | |||
17 | [[Image(Rita:trf6151_serial_2.png)]] |
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18 | 3 | laforge | |
19 | The timings have been confirmed by the measurements below: |
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20 | |||
21 | [[Image(Rita:trf6151_tsp.png)]] |
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22 | 4 | laforge | |
23 | == Analog I/Q baseband output == |
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24 | |||
25 | During development I've taken some measurements of the I/Q output of the TRF6151. |
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27 | The green and black graph of the diagrams below are the "I" channel positive and negative signal. |
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28 | The magenta graph is the difference signal computed by the Scope. |
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29 | |||
30 | === baseband output in idle mode listening on paging channel === |
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32 | This is zoomed out to a very long timebae to see the Rx activity at 1.8 second intervals, |
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33 | which apparently was the paging channel for the paging group of that IMSI. |
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34 | |||
35 | [[Image(Rita:trf6151_iq_rx_paging_channel.png)]] |
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36 | |||
37 | === multiple consecutive bursts === |
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38 | |||
39 | This shows multiple consecutive received bursts. |
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40 | You can see that there is a DC offset when the TRF6151 is powered up, but you can't really see data on that DC offset |
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41 | |||
42 | [[Image(Rita:trf6151_iq_rx_burst_distance.png)]] |
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43 | |||
44 | === a single burst === |
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45 | |||
46 | [[Image(Rita:trf6151_rx_iq_one_burst.png)]] |
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47 | |||
48 | === bits of a burst === |
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49 | |||
50 | [[Image(Rita:trf6151_rx_iq_bits_of_burst.png)]] |